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USFWS Biological Opinion on Oregon's Water Quality Standards for Temperature

July 1, 1999







Randall F. Smith
Director, Water Division
U.S. Environmental Protection Agency, Region X
1200 Sixth Avenue
Seattle, Washington 98101


Subject: Oregon water quality standards ESA consultation


Dear Mr. Smith:

The U.S. Fish and Wildlife Service (FWS) has reviewed the September 15, 1998, biological assessment for the U.S. Environmental Protection Agency (EPA) proposed approval of the 1996 revisions to the State of Oregon’s water quality standards (WQS). Your request for formal consultation was received on September 22, 1998. This document represents the FWS’s biological opinion on the effects of the proposed action on bull trout (Salvelinus confluentus), Lahontan cutthroat trout (Oncorhynchus clarki henshawi), Oregon chub (Oregonichthys crameri), Borax Lake chub (Gila boraxobius), Hutton Spring tui chub (Gila bicolor ssp.), Lost River sucker (Deltistes luxatus), shortnose sucker (Chasmistes brevirostris), Warner sucker (Catostomus warnerensis), Foskett speckled dace (Rhinichthys osculus ssp.), vernal pool fairy shrimp (Branchinecta lynchi), Oregon spotted frog (Rana pretiosa), and Columbia spotted frog (Rana luteiventris) in accordance with section 7 of the Endangered Species Act (ESA) of 1973, as amended (16 U.S.C. 1531 et seq.).

The FWS acknowledges the efforts of the Oregon Department of Environmental Quality (ODEQ) in their extensive review of these water quality standards. We commend them on their standard revisions aimed at improving conditions for the benefit of native aquatic species. In addition, we appreciate the work of EPA in producing a very thorough biological assessment and conducting this consultation in a very positive and cooperative manner.

This biological opinion is based upon information provided in EPA’s biological assessment, ODEQ’s review of the water quality standards and their adopted revisions, information contained within FWS files, a review of the relevant published literature, and numerous meetings and telephone conversations between our staffs. A complete administrative record of this consultation is on file in the FWS Oregon State Office.

Consultation History

In 1992, the Oregon Department of Environmental Quality (ODEQ) began a triennial review of five of the State’s water quality standards (standards). For each standard under review, the process entailed assembling a technical committee made up of members drawn from scientific and regulatory agencies, academia, and the regulated community. The technical committee conducted a thorough review and deliberation of the scientific literature to develop a basis for establishing criteria supportive of critical native species and their sensitive life stages. Suggestions for revising the standards were then provided to a policy advisory committee who developed workable recommendations for public review. Based upon all the information gathered, ODEQ formulated revisions to the standards which Oregon adopted through a formal rulemaking process. Revised standards were submitted to EPA for approval in July 1996. EPA commenced a review of the standards along with the consultation process in January 1997. Key activities associated with the consultation are described in chronological order in Appendix I.

Twenty-seven Federally protected species under the FWS’ jurisdiction that may occur in Oregon and that are associated with aquatic ecosystems were initially considered (Table 1). Of these, 10 are considered in further detail within this biological opinion.

Table 1. Federally listed species (threatened, endangered, and proposed species) in Oregon related to aquatic environments and considered in the consultation for EPA’s proposed approval of Oregon’s revised water quality standards. Shading indicates species is considered in detail within this biological opinion.

Common Name	Scientific Name	Status
Plants
Macdonald’s rockcress	Arabis macdonaldiana	E
Applegate’s milk-vetch	Astragalus applegatei	E
Golden Indian paintbrush	Castilleja levisecta	T
Howellia	Howellia aquatilis	T
Bradshaw’s lomatium	Lomatium bradshawii	E
MacFarlane’s four o’clock	Mirabilis macfarlanei	T/CH
Western Lily	Lilium occidentale	E
Nelson’s checker-mallow	Sidalcea nelsoniana	T
Willamette daisy	Erigeron decumbens var. decumbens	PE
Rough popcorn flower	Plagiobothrys hirtus	PE
Howell’s spectacular thelypody	Thelypodium howellii ssp. spectabilis	PT
Invertebrates
Vernal pool fairy shrimp	Branchinecta lynchi	T
Amphibians
Oregon spotted frog	Rana pretiosa	C
Columbia spotted frog	Rana luteiventris	C
Fishes
Bull trout	Salvelinus confluentus	T
Lahontan cutthroat trout	Oncorhynchus clarki henshawi	T
Oregon chub	Oregonichthys(=Hybopsis) crameri	E
Borax Lake chub	Gila boraxobius	E/CH
Hutton Spring tui chub	Gila bicolor ssp.	T
Lost River sucker	Deltistes luxatus	E/PCH
Shortnose sucker	Chasmistes brevirostris	E/PCH
Warner sucker	Catastomus warnerensis	T/CH
Foskett speckled dace	Rhinichthys osculus ssp.	T
Birds
Marbled murrelet	Brachyramphus marmoratus	T/CH
Aleutian Canada goose	Branta canadensis leucopareia	T
Western snowy plover (coastal populations)	Charadrius alexandrinus nivosus	T/PCH
Bald eagle	Haliaeetus leucocephalus	T
Brown pelican	Pelecanus occidentalis	E
Mammals
Columbian white-tailed deer	Odocoileus virginianus leucurus	E

E-Listed Endangered CH- Critical Habitat has been designated for this species
T- Listed Threatened P- The listing or critical habitat designation has been proposed for this species
C- Candidate


In scoping meetings between EPA and the Services (FWS and National Marine Fisheries Service), it was determined that the following species would not be directly impacted by revisions to the dissolved oxygen (DO), temperature, or pH criteria: bald eagle, brown pelican, marbled murrelet, western snowy plover, Aleutian Canada goose, Columbian white tailed deer and listed plants. The agency discussions noted that fish and invertebrate eating birds (bald eagle, brown pelican, marbled murrelet, western snowy plover) rely on a varied prey base where only limited indirect effects would be expected. The Aleutian Canada goose relies on water for drinking and floating and changes in the conventional standards should not affect the goose’s ability to carry out these activities. For the listed plants and the Columbian white tailed deer, primary exposure to water quality impacts would be experienced through drinking water or habitat alterations, neither of which is likely to be significantly affected by the proposed revisions to the standards. Thus, within their biological assessment, EPA made the determinations that these species would not likely be adversely affected by their approval action.

Listed species which are predominantly aquatic have much greater potential to be affected by this action, while terrestrial species which use aquatic systems for only certain aspects of their life cycles could be indirectly affected. The FWS believes that for the conventional parameters considered in this consultation (temperature, pH, and dissolved oxygen), when aquatic species are protected, the terrestrial species will also be protected. Within the BA, an assumption is identified that temperature standards established on the basis of thermal requirements of salmonids are usually protective of other biotic components of the ecosystem and, it seems reasonable to use the thermal requirements of salmonid life stages as keystone indicators of the seasonal thermal requirements of stream segments. Although the BA is referring specifically to invertebrates, we believe this reasoning also holds for other aquatic as well as terrestrial species. Therefore, we concur with EPA’s determination of not likely to adversely affect for the bald eagle, brown pelican, marbled murrelet, western snowy plover, Aleutian Canada goose, Columbian white tailed deer and all of the listed plants identified in Table 1.


DESCRIPTION OF THE PROPOSED ACTION
Under section 303(c) of the Clean Water Act (CWA), states are required to adopt water quality standards to restore and maintain the chemical, physical and biological integrity of the Nation’s waters. Once adopted by the state, water quality standards are submitted to EPA for approval or disapproval. The approval or disapproval of the standards hinges upon EPA’s review to determine whether: 1) the analyses performed are adequate, 2) the designated uses are appropriate, and 3) the criteria are protective of those uses. State standards are then reviewed and revised, where appropriate, on a triennial basis. ODEQ submitted revised water quality standards for dissolved oxygen (DO), temperature, pH, bacteria, and groundwater nitrate to EPA for review and approval on July 11, 1996.

The action proposed by EPA for this consultation is the approval of Oregon’s water quality standards for DO, temperature, and pH, as submitted, with the exception of the temperature criterion for the Willamette River, mouth to river mile 50. Consultation for the temperature criteria for the Willamette River, mouth to river mile 50, will be deferred until a final action (approval of a revised State criterion or a new criterion promulgated by EPA) is proposed by EPA. Groundwater nitrate and bacteria standards are not addressed in this consultation because EPA has no approval authorities for groundwater standards under the CWA and EPA determined that there will be no effect on endangered species from the approval of the bacteria standard.

Portions of the narrative standards were revised during this triennial review. In several of these cases, enacting these narrative standards would require a site-specific criterion to be developed. Site-specific criteria require EPA review and approval, and accordingly, future consultation under section 7 of the ESA. In addition, the temperature standard contains certain provisions which either do not fall under the purview of CWA Section 303(c) water quality standards review or require development of a site-specific criterion which would be submitted to EPA for review, approval and consultation under the ESA. Consequently, these narrative standards and provisions are not considered within this BO.

The ODEQ submitted a Policy Letter to EPA on June 22, 1998 (Attachment 1), clarifying how some of the provisions of their new standards would be implemented. This letter is included as an appendix in the BA and is relied upon by EPA in evaluating the impact of their action. The letter clearly states that regulatory clarifications included in this letter will be incorporated into the water quality standards to the extent possible during the next triennial review.

During this consultation process, EPA and ODEQ worked with the Services to develop conservation measures intended to address adverse effects of the DO and temperature standards on listed aquatic species. These measures are explained in Attachment 3. Subsequently, EPA modified their proposed action in a letter dated June 17, 1999, to include the following conservation measures. First, EPA will establish and lead a Regional Temperature Criteria Development Project over the next two years. The project will involve assembling three workgroups (technical, scientific peer review and policy) made up of federal, state, and tribal representatives to develop and recommend to EPA a more ecologically relevant temperature criteria protective of all salmonid life history stages. It is intended that this temperature criteria will be formally accepted by EPA Region 10 and recommended for adoption by Pacific Northwest states and tribes. It is expected the final product will be used by ODEQ to revise the current temperature standard in the next triennial review. A full description of the Regional Temperature Criteria Development Project is included as Attachment 4 of this document. Second, EPA will provide a grant to the State of Oregon to assist them in carrying out specific State Conservation Measures outlined in Attachment 3 of this document. These funds are provided under section 104(b)3 of the Clean Water Act. These measures are intended to assure that the standards are being properly applied to protect threatened and endangered species.

The FWS has evaluated the effects of approving the revised standards as the proposed action. Whether or not these criteria can be achieved throughout Oregon waters is largely dependent upon implementation of these criteria through the State water quality program (an overview is presented in the BA). Therefore, for the purposes of this analysis, we assume that Oregon will responsibly implement the components of their water quality program.

Action Area
The action area of this consultation is considered to be all Oregon surface waters for which revised DO, temperature, and pH criteria apply. Water quality standards apply to all surface waters of the state, defined as all lakes, bays, ponds, impounding reservoirs, springs, rivers, streams, creeks, estuaries, marshes, inlets, canals, the Pacific Ocean within the territorial limits of the State of Oregon, and all other bodies of surface waters, natural or artificial, inland, or coastal, fresh or salt, public or private (except those which do not combine or effect a junction with natural surface or underground waters), which are wholly or partially within or bordering the state or within its jurisdiction [OAR 340-41-006 (14)]. EPA’s action does not apply to any waters within Indian Country.



Specific Revisions
The revised standards now under review were adopted by ODEQ in 1996 and since that time they have been applying the standards to waters of the state. EPA’s action would not change existing water quality standards, therefore, we do not consider the previous standard in this analysis. Revised standards are written below, without the previous standard. The BA contains information on the previous standard, the objective of the revisions, and the revised standard.

Dissolved Oxygen Criteria
salmonid spawning (spawning until fry emergence from the gravels):

Dissolved oxygen not less than 11 mg/l, measured as a seven day mean minimum (the minimum of seven consecutive day floating average of the calculated daily mean DO concentration).
If the minimum intergravel dissolved oxygen (IGDO) is 8.0 mg/l or greater (measured as the spatial median), then the DO criterion is 9.0 mg/l.

The absolute minimum, including seasonal and diurnal minimums, allowable DO concentration is 9.0 mg/l.

Where conditions of barometric pressure, altitude, and temperature preclude attainment of the 11.0 mg/l or 9.0 mg/l criteria, DO levels shall not be less than 95% saturation.

Intergravel dissolved oxygen shall not fall below 6.0 mg/l.
An IGDO of 8.0 mg/l to be used to identify areas where the recognized beneficial use may be impaired and require action by the Department. Action by the ODEQ at this level will be in accordance with established priorities for evaluating water quality impaired waterbodies.

Where the naturally occurring quality parameters of waters are outside the numerical limits of the above assigned water quality standards, the naturally occurring water quality shall be the standard.

cold water aquatic life:

Not less than 8.0 mg/l as an absolute minimum.

Where conditions of barometric pressure, altitude, and temperature preclude attainment of the 8.0 mg/l, dissolved oxygen shall not be less than 90% of saturation.

At the discretion of ODEQ, when ODEQ determines adequate information exists, the DO shall not fall below 8.0 mg/l as a 30-day mean minimum, 6.5 mg/l as a seven-day minimum mean, and 6.0 mg/l as an absolute minimum.

cool water aquatic life:

Not less than 6.5 mg/l as an absolute minimum.
At the discretion of the ODEQ, when the ODEQ determines adequate information exists, the DO shall not fall below 6.5 mg/l as a 30-day mean minimum, 5.0 mg/l as a seven-day minimum mean, and 4.0 mg/l as an absolute minimum.

warm water aquatic life:

Not less than 5.5 mg/l as an absolute minimum.
At the discretion of the ODEQ, when the ODEQ determines adequate information exists, the DO shall not fall below 5.5 mg/l as a 30-day mean minimum, and 4.0 mg/l as an absolute minimum

Temperature Criteria
Numeric
Unless specifically allowed under a ODEQ-approved surface water temperature management plan, no measurable surface water temperature increase resulting from anthropogenic activities is allowed:

In a basin for which salmonid fish rearing is a designated beneficial use, and in which surface water temperatures exceed 64°F (17.8° C).

In the Willamette River or its associated sloughs and channels from the mouth to river mile 50 when surface water temperatures exceed 68°F (20.0°C).
EPA proposes to disapprove this standard

In waters and periods of the year determined by the ODEQ to support native salmonid spawning, egg incubation, and fry emergence from the egg and from the gravels in a basin which exceeds 55.0 °F (12.8°C).

In waters determined by the ODEQ to support or to be necessary to maintain the viability of native Oregon bull trout when surface water temperatures exceed 50.0°F (10.0°C).

Narrative
No measurable surface water temperature increase resulting from anthropogenic activities:

In waters determined by the ODEQ to be ecologically significant cold-water refugia.

In stream segments containing federally listed Threatened and Endangered species if the increase would impair the biological integrity of the Threatened and Endangered population.

In Oregon waters when the dissolved oxygen levels are within 0.5 mg/l or 10% saturation of the water column or intergravel DO criterion for a given stream reach or subbasin.

In natural lakes.

Provisions

An exceedance of the numeric criteria will not be deemed a temperature standard violation if it occurs when the air temperature during the warmest seven-day period of the year exceeds the 90^th percentile of the seven-day average daily maximum air temperature calculated in a yearly series of the historic record.

Measurement
The numeric temperature criterion is measured as the seven-day moving average of the daily maximum temperatures. If there are insufficient data to establish a seven-day average of maximum temperatures, the numeric criteria shall be applied as an instantaneous maximum.

Rule Language
In addition to revising numeric standards, the state incorporated rule language to address waterbodies exceeding the relevant numeric temperature criteria and included on the state’s 303(d) list. The rules require that anthropogenic sources develop and implement a surface water temperature management plan which describes the best management practices, measures, and/or control technologies which will be used to reverse the warming trend of the basin, watershed, or stream segment identified as water quality limited for temperature.

ODEQ Clarification
In their letter to EPA clarifying policy of the Oregon water quality standards revisions, ODEQ (Attachment 1) states the following:

The Department will use the 1997 Bull Trout distribution maps contained in the 1997 ODFW publication to clarify the phrase “waters determined by the Department to support or be necessary to maintain the viability of native Oregon Bull Trout.”. The temperature of 50°F applies to the stream reaches which indicate that “Spawning, Rearing, or Resident Adult Bull Trout” populations are present. The mapping and planning effort is an on-going effort by ODFW. Any changes made to the mapped distribution will represent a change in the standard which would be submitted to EPA for approval. The Bull Trout portion of the standards will be revised to incorporate a reference to the 1997 ODFW publication or identify any other means for determining waters that support or are necessary to support Bull Trout in the next triennial standards review.

As stated above, ODEQ has agreed to clarify the standards phrase, “waters determined by the Department to support or to be necessary to maintain the viability of native Oregon Bull Trout.” to which bull trout criterion will be applied. Based upon conversations with ODEQ staff (Sturdevant, ODEQ, pers. comm., 1998), the FWS interprets this to mean identification of critical migratory corridors which will be included in the bull trout beneficial use designation.


pH criteria
pH values shall not fall outside the following ranges:
North, Mid, and South Coast Basins

Marine waters 7.0 to 8.5
Estuarine and fresh waters 6.5 to 8.5

Umpqua and Rogue Basins

Marine waters 7.0 to 8.5
Estuarine and fresh waters (except Cascade lakes) 6.5 to 8.5
Cascade lakes above 3,000 feet altitude 6.0 to 8.5

Willamette, Sandy, Hood, Deschutes Basins

Columbia River 7.0 to 8.5
All other basin waters (except Cascade lakes) 6.5 to 8.5
Cascade lakes above 3,000 feet altitude 6.0 to 8.5

Klamath Basin

Freshwaters (except Cascade lakes) 6.5 to 9.0*
Cascade lakes above 5,000 feet altitude 6.0 to 8.5

John Day and Umatilla Basins

Columbia River 7.0 to 8.5
All other basin streams 6.5 to 9.0*

Walla Walla Basin

6.5 to 9.0*

Grande Ronde and Powder Basins

Snake River 7.0 to 9.0
All other basin streams 6.5 to 9.0*

Malheur, Owyhee, and Malheur Lake Basins

7.0 to 9.0*

Goose and Summer Lakes Basins

Goose Lake 7.5 to 9.5
All other basin waters 7.0 to 9.0*

* when greater than 25% of ambient measurements taken between June and September are greater than pH 8.7, and as resources are available according to priorities set by the Department, the Department shall determine whether the values higher than 8.7 are anthropogenic or natural in origin

Exception applying to all Basins: Waters impounded by dams existing on January 1, 1996, which have pHs that exceed the criteria shall not be considered in violation of the standard if the Department determines that the exceedance would not occur without the impoundment and that all practicable measures have been taken to bring the pH in the impounded waters into compliance with the criteria.


STATUS OF THE SPECIES
Species Accounts
Portions of the following life history sections were largely taken from EPA’s biological assessment.

Bull trout (Salvelinus confluentus) - Columbia River Basin Distinct Population Segment (DPS): Threatened OR, WA, ID, MT 6/10/98, 62FR32268.

At the time of the FWS threatened listing (6/10/98, 63FR31647) of this bull trout distinct population segment (DPS), critical habitat was not designated.

The Columbia River population segment is from the northwestern United States. This population segment, comprised of 386 bull trout populations in Idaho, Montana, Oregon, and Washington, is threatened by habitat degradation, passage restrictions at dams, and competition from non-native lake and brook trout. The Columbia River population segment includes the entire Columbia River basin and all its tributaries, excluding the isolated bull trout populations found in the Jarbidge River in Nevada. Bull trout populations within the Columbia River population segment have declined from historic levels and are generally considered to be isolated and remnant.

DPS status. Limited historical references indicate that bull trout in Oregon were once widely distributed in 12 basins in the Klamath and Columbia river systems. Bull trout are estimated to have occupied about 60 percent of the Columbia River Basin, and presently occur in 45 percent of the estimated historical range. The Columbia River population segment is composed of 141 sub-populations. Thirty of these sub-populations are in Oregon. In the Columbia River basin, water bodies designated as water quality limited by Oregon, Washington, Idaho, and Montana are estimated to apply to at least 64 of the 141 bull trout subpopulations.


Bull trout (Salvelinus confluentus) - Klamath Basin DPS

The Klamath River population segment from south-central Oregon is now listed as threatened (OR 6/10/98, 63FR31647). This population segment, comprised of seven bull trout subpopulations, is threatened by habitat degradation, irrigation diversions, past and present land management practices, logging and road building activities, and competition and hybridization with non-native species. Bull trout in the Klamath River drainage are discrete because of physical isolation by the Pacific Ocean and several small mountain ranges in central Oregon. Perhaps the most significant threat to the remaining bull trout populations in the Klamath Basin is hybridization with introduced brook trout. The FWS found that designation of critical habitat (as per section 4 of the ESA) for this species was not determinable at the time of listing.

DPS status. Within the Klamath Basin streams, bull trout occurred in 15 basin streams between 1948 and 1979. By 1989, the distribution of the species had been restricted to 10 streams in the basin. The most recent data provided in the 1994 record suggested that in 1991, only seven segregated resident populations still occurred in the basin and were confined to headwater streams in the Sprague, Sycan, and Upper Klamath Lake sub-basins. The largest areas occupied by any of the seven populations is 2.5 stream miles (9 km), and basinwide, 12.5 miles (34.1 km) of stream is inhabited by bull trout. Populations in the Upper Klamath Lake subbasin are at precarious abundance levels, and at a high risk of extinction. The remaining populations are disconnected from each other, and are considered to be isolated, remnant groups from a historically larger, more diverse metapopulation; the populations are at a moderate or high risk of extinction. In the Klamath River basin, stream reaches designated as water quality limited (ODEQ 1996) are estimated to apply to six of the seven bull trout subpopulations.

Life history of bull trout throughout Oregon (both Columbia and Klamath DPSs)
The bull trout in Oregon have three life-history patterns represented by resident, fluvial, and adfluvial fish. Resident bull trout are believed to spend their entire lives in the same stream in which they hatched. Fluvial populations generally migrate between smaller streams used for spawning and early juvenile rearing and larger rivers used for adult rearing. Adfluvial populations generally migrate between smaller streams used for spawning and juvenile rearing and lakes or reservoirs used for adult rearing. Fluvial populations can switch to adfluvial under some circumstances. Adfluvial individuals can attain sizes over 9 kg in Oregon.

At all life stages, bull trout display a high degree of sensitivity to environmental disturbance and have more specific habitat requirements than many other salmonids. Bull trout growth, survival, and long-term population persistence appear to be particularly dependent upon five habitat characteristics: (1) cover, (2) channel stability, (3) substrate composition, (4) temperature, and (5) migratory corridors.

Spawning/Temperatures. Since bull trout life history patterns include migratory and resident forms, both adults and juveniles are present in the streams throughout the year. Bull trout adults may begin to migrate from feeding to spawning grounds in the spring and migrate slowly throughout the summer (Pratt 1992). In Oregon, most bull trout spawn in September and October, though populations in the Metolius River basin can begin as early as July (Bellerud et al. 1997; Buchanan et al. 1997) and mid to late August in the Klamath basin (Klamath Basin Bull Trout Working Group, unpublished data). Summer temperatures are, therefore, a concern for resident survival, migration, spawning, and egg incubation in the late summer and early fall. These trout are stenothermal, requiring a narrow range of temperature conditions to reproduce and survive. Bull trout densities are highest at water temperatures of 12°C or less; no bull trout were found during surveys when water temperatures were above 18°C (Shepard et al. 1984; ODEQ 1994). Ratliff (1992) found in the Metolius River watershed, Oregon, that bull trout spawning and the initial 1-year juvenile rearing is limited to streams with temperatures of about 4.5°C. Optimum incubation temperatures are 2-4°C. Such strict temperature tolerances predispose bull trout to population declines resulting from any activity occurring in a watershed that leads to increased stream temperatures. A study of the distribution of juvenile bull trout in a thermal gradient of a plunge pool in Granite Creek, Idaho, revealed that fish chose the coldest water available (8-9°C.), Bonneau and Scarnecchia (1996).

Hatching and Rearing. Hatching is completed after 100-145 days usually in winter (Pratt 1992). Bull trout alevins require 65-90 days after hatching to absorb their yolk sacs (Pratt 1992). They remain within the interstices of the streambed as fry for up to three weeks before filling their air bladder, reaching lengths of 25-28 mm, and emerging from the streambed in late April (McPhail and Murray 1979, Pratt 1992). An extremely long period of residency in the gravel (200 or more days) makes bull trout especially vulnerable to fine sediments and water quality degradation.

Juvenile bull trout are closely associated with the streambed and are found immediately above, on, or within the streambed (Pratt 1984, 1992). Goetz (1991) and Pratt (1984, 1992) reported that young bull trout most frequently used woody debris as cover. As fish mature they seek out deep water habitat types such as pools and deep runs (Pratt 1984, Shepard et al. 1984).

Bull trout less than 110 mm feed primarily on aquatic insects, while larger bull trout are primarily piscivorous (Shepard et al. 1984). Juvenile bull trout may migrate from natal areas during spring, summer or fall; migration may be nocturnal (Pratt 1992).

Adult Migration. Adfluvial bull trout feed primarily on fish and can exhibit extraordinary growth rates (Shepard et al. 1984, Pratt 1992). Resident bull trout have much slower growth rates. Adult bull trout rearing and migration patterns are not well documented in Oregon except for the Metolius River and Lake Billy Chinook system. Bull trout migration typically starts in mid-July; fish move quickly upriver and reside near the mouth of the intended spawning tributary. Migration into the spawning tributary, spawning, and migration back to the mainstem usually takes one month. Surveys in Oregon document bull trout spawning from late July through at least October. Most spawning occurs in cold headwaters or spring-fed streams. In the Metolius River, spawning adults and initial juvenile rearing are limited to very cold (approximately
4.5°C.) spring-fed tributaries to the Metolius River (Ratliff 1992). Annual and alternate year spawning is documented for bull trout (Shepard et al. 1984).

Habitat. The habitat requirements of bull trout vary by age and season of the year (Rieman and McIntyre 1993), but they appear to have more specific habitat requirements than other salmonids. Many investigators have concluded that water temperatures represent a critical habitat characteristic for bull trout (Buchanan et al. 1997). Young-of-the-year fish initially seek stream margins with heterogenous habitat structure. Seven habitat variables were found to be significant (P < 0.0001) descriptors of the presence of juvenile bull trout: (1) high levels of shade, (2) high levels of undercut banks, (3) large woody debris volume, (4) relatively large pieces of woody debris, (5) high levels of gravel in riffles, (6) low levels of fine sediment in riffles, and (7) low levels of bank erosion (Dambacher and Jones 1997). Although bull trout may be present throughout large river basins, spawning and rearing fish are often found only in a portion of available stream reaches (Fraley and Shepard 1989, Shepard et al. 1984, Mullan et al. 1992). Where this habitat is not present or has been lost, juvenile bull trout populations are virtually eliminated. Migratory corridors are needed to connect wintering, summering, or rearing areas to spawning areas as well as to allow the movement for interactions of local populations within possible metapopulations.

Threats
Threats to bull trout include, but are not limited to, habitat degradation and fragmentation, blockage of migratory corridors, poor water quality, past fisheries management practices, and the introduction of non-native species such as brown, lake, and brook trout or hybridization and competition where these exotics have already been introduced.

Conservation Needs
Objectives of Bull Trout Interim Conservation Guidance (USFWS 1998a) related to the water quality parameters being considered in this biological opinion include: 1) maintaining or restoring temperature regimes that support bull trout at all life history stages, including migratory corridors; 2) maintaining or restoring cold water temperature contributions of intermittent and non-fish bearing tributaries to bull trout streams; 3) decreasing the risk of invasion and displacement by introduced species by preventing increases in water temperature; 4) providing or maintaining sufficient thermal refugia to support residence throughout summer months; 5) protecting all ground water sources that may influence stream temperatures; 6) maintaining or restoring water quality within a range that maintains the biological, physical, and chemical integrity of bull trout watersheds; 7) maintaining and restoring floodplain, riparian, and channel processes, including hydrologic regimes, sediment inputs and transport, channel configuration, and bank characteristics, to resemble watershed-specific historic or expected conditions to the greatest extent possible; 8) maintaining or improving connectivity among occupied habitats and refugia by removing human-caused physical, thermal, and chemical barriers within and among isolated subpopulations; and 9) restoring occupiable habitat.


Lahontan cutthroat trout (Oncorhynchus clarki henshawi): (The following life history information is taken from ODFW (1996), Species at Risk; 40FR29863, 7/16/75; Recovery Plan (USFWS 1995).

The Lahontan cutthroat trout is listed as threatened under the ESA (35FR16047, 10/13/70; 40FR29863, 7/16/75). Critical habitat has not been designated.

Historically, Lahontan cutthroat trout (LCT) were found in a wide variety of cold-water habitats including large terminal alkaline lakes, oligotrophic alpine lakes, slow meandering low-gradient rivers, moderate-gradient montane rivers, and small headwater tributary streams (USFWS 1995). Riverine LCT inhabit small streams characterized by cool water, pools in close proximity to cover and velocity breaks, well vegetated and stable stream banks, and relatively silt free rocky substrate in riffle-run areas. Fluvial LCT generally prefer rocky areas, riffles, deep pools, and habitats near overhanging logs shrubs or banks.

In congruence with the variety of habitats that they have inhabited, LCT appear to have tolerances to a wide range of water quality conditions. LCT inhabiting small tributary streams have been reported to tolerate temperatures exceeding 27°C for short periods of time and daily fluctuations of 14 to 20°C. Lacustrine LCT populations have adapted to a wide variety of lake habitats from small alpine lakes to large desert waters, tolerating alkalinity and total dissolved solid levels as high as 3,000 mg/l and 10,000 mg/l respectively.

LCT is an obligate stream spawner, and depending upon stream flow, elevation, and water temperature, can spawn from April through July. Lake residents migrate up tributaries to spawn in riffles or tail ends of pools. LCT generally spawn in riffle areas over gravel substrate. Spawning migrations have been observed in water temperature ranging from 5 to 16°C. Eggs generally hatch in 4 to 6 weeks and fry emerge 13 to 23 days later.

Stream resident LCT are opportunistic feeders, with diets consisting of drift organisms, typically terrestrial and aquatic insects. In lakes, small LCT feed primarily on insects and zooplankton, while large LCT feed on fish.

The majority of the current LCT range exists in Nevada with some extension into California and Oregon. This subspecies has been reintroduced into several stream systems (NV 11, OR 9, CA 9, UT 4), which, along with habitat restoration, allowed the FWS to change the listing status from endangered to threatened (40FR29864).

In Oregon, LCT are found primarily in streams of the Quinn River and Coyote Lake basins in southeast Oregon. The Coyote Lake basin has the only native population of Lahontan cutthroat trout in Oregon that is without threat of hybridization and is broadly distributed throughout a drainage. In October 1994, the number of Lahontan cutthroat in the basin was estimated at 39,500 fish, and fish were limited to 56 km of the potential 114 km of available stream habitat (Jones et al. 1998). Distribution was limited by dry channels and thermal and physical barriers to movement, which created two disconnected populations in the Willow Creek and Whitehorse Creek drainages. The Whitehorse Creek subbasin population has been fragmented by numerous barriers into four discreet local populations. The Willow Creek subbasin is largely free of migration barriers.

Riparian and upland habitats have been degraded by intensive grazing of cattle and sheep during the past 130 years, but the overall status of Lahontan cutthroat trout is improving due to recently improved grazing management. Drought and cold periods during the past decade have further affected the quantity and quality of the aquatic habitat. The ability of local populations to interact is important to the long-term viability of a metapopulation. Seasonally, all streams in the drainages have disjunct populations because of high summer temperatures (>26°C) or dry channels.

Threats
Lahontan cutthroat trout are listed as threatened under the ESA because of poor habitat conditions including channel modifications, dewatering, passage barriers and loss of riparian vegetation. Introgression with rainbow trout and displacement by introduced brown trout and brook trout have extirpated Lahontan cutthroat in several stream systems. Brook trout are a strong competitor for food and space with the Lahontan cutthroat.

Conservation Needs
The Lahontan cutthroat trout Recovery Plan (USFWS 1995) lists strategies for recovery which include: 1) manage and secure habitat to maintain all existing LCT populations; 2) establish 148 self-sustaining fluvial LCT populations within native range and determine appropriate numbers to assure persistence for the next 100 years; 3) implement research and perform population viability analyses to validate recovery objectives; and 4) revise recovery plan. The recovery plan also lists the following general guidance for optimal cutthroat trout habitat parameters related to water quality: 1) clear cold water with an average maximum summer temperature of <22°C; 2) specific to fluvial populations, relatively stable summer temperature averaging 13°C + 4°C; and 3) specific to lacustrine habitat, a mid-epilimnion pH of 6.5 to 8.5 and dissolved oxygen content > 8 mg/l in the epilimnion.


Oregon chub (Oregonichthys crameri): (The following life history information is taken from 58FR53800, 10/18/93; and USFWS Recovery Plan 1998b).

The endangered-status ruling for Oregon chub was issued on October 18, 1993 (58FR53800). Critical habitat has not been designated.

The genus Oregonichthys is endemic to the Umpqua and Willamette Rivers. Historically, the Oregon chub was distributed throughout the lower elevation backwaters of the Willamette River drainage. Now, known established populations are primarily restricted to an 18.6 mile stretch of the Middle Fork Willamette River.

The current distribution of Oregon chub is limited to 20 known naturally occurring populations and four recently reintroduced populations. Only seven of the naturally occurring populations exceed 1,000 fish and 12 populations contain fewer than 100 individuals. Of the 24 known populations, the sites with the highest diversity of native fish, amphibian, and reptile species have the largest populations of Oregon chub (Scheerer and Apke 1998). Beaver appear to be especially important in creating and maintaining habitats that support these diverse native species assemblages.

Habitat of the Oregon chub is typified by off-channel slack waters such as beaver ponds, oxbows, side channels, backwater sloughs, low gradient tributaries and flooded marshes. These habitats usually have low- or zero-velocity water flow, silty organic substrates, and abundant aquatic or overhanging riparian vegetation. Average depth is typically less than 2 meters and summer temperatures typically exceed 16°C.

Spawning occurs from the end of April through September when water temperatures range from 16 to 28°C. Oregon chub are obligatory sight feeders, feeding throughout the day and stopping after dusk.

Threats
Decline of the Oregon chub is attributed to changes in, and elimination of, its backwater habitats. The decline coincides with construction of flood control structures which have altered historical flooding patterns and eliminated much of the river’s braided channel pattern. Introduction of non-indigenous species have also contributed to the Oregon chub's decline

Conservation Needs
The recovery effort for the Oregon chub focuses on protecting, restoring and enhancing populations, with the first priority being maintenance of existing populations (USFWS 1998b). Planned reintroduction of the species will be necessary to maintain weaker populations, and to expand the currently restricted range. The recovery plan also acknowledges that research and public outreach are necessary components of this effort.


Borax Lake chub (Gila boraxobius): (The following life history information is excerpted from USFWS Borax Lake Chub Recovery Plan (1987); and Scappetone et al. 1995).

The Borax Lake chub was listed as endangered under an emergency rule (45FR35821, 5/28/80) with a final endangered listing on (47FR43957, 10/5/82). Critical habitat is designated as Borax Lake and the aquatic environments associated with its outflow (47FR43960, 10/02/92).

The Borax Lake chub is endemic to Borax Lake and adjacent wetlands in the Alvord Basin, Harney County, Oregon. The Borax Lake area is a part of the Great Basin physiographic province, and as such, is characterized by an endorheic (i.e., internal) water drainage pattern. The lake is naturally fed from waters of several thermal springs and is perched atop large sodium-borate deposits in the Alvord Desert. The temperature of the springs is 35-40°C; lake temperatures vary from 17 to 35°C but are often 29 to 32°C. Borax Lake has broad temperature fluctuations due to its large surface to volume ratio (Scoppettone 1995). The lake averages less than one meter deep, 4.1 ha in size, with a pH of 7.3. In a survey of Borax Lake conditions from 1991-1993, DO measurements ranged from 4.98 to 8.66 mg/l and pH ranged from 7.3 to 7.9 (Scoppettone 1995). The Borax Lake chub is also recorded from Lower Borax Lake, the marsh area between Borax and Lower Borax Lake, the smaller southern marsh, and adjacent ponds, as well as the southwest outflow creek.

Borax Lake chub appear to have a broad thermal tolerance. The fish avoid lake temperatures above 34°C. In laboratory experiments, Borax Lake chub lose equilibrium in water above about 34.5°C. If adequate water levels in Borax Lake are not maintained, chub are forced into potentially lethal hot spring inflows at the bottom of the lake. Fish kills occurred when lake temperatures have locally exceeded 38°C.

Early investigators considered the Borax Lake chub so distinct that the fish might be set apart in a new genus. Because of the striking differentiation of these chubs, they were considered to be geographically isolated from their nearest relatives in adjacent basins, since the Pliocene. The Borax Lake chub was described as a dwarf (33-50 mm length, for typical adults) relative of the Alvord chub which is widespread in the Alvord basin.

Given the relatively constant thermal environment of Borax Lake, the Borax Lake chub spawns throughout the year, though most spawning occurs in March and April. Individual females may spawn twice annually. Young-of-the-year are prominent in Borax Lake during May and June. They are most often found in the very shallow coves around the margin of the lake. No young-of-the-year (YOY) have been collected from Lower Borax Lake and are seldom observed in adjacent marshes, which indicates that most if not all spawning occurs in Borax Lake. Most Borax Lake chub live approximately one year. Adults are fairly evenly distributed throughout the lake, although their primary foraging area appears to be the flocculent layer on the bottom of the lake (Scoppetone 1995).

Borax Lake chub are opportunistic omnivores following seasonal fluctuations. The importance of diatoms and microcrustaceans in the diet increases substantially during winter, while the consumption of terrestrial insects decreases dramatically. Chubs often pick foods from soft bottom sediments, but also are observed feeding throughout the water column and at the surface. Within the relatively simple food web in Borax Lake, the Borax Lake chub may function as a "keystone" species controlling the structure in the invertebrate community of Borax Lake by feeding on the most abundant species encountered.

Threats
Borax Lake is located above borate deposits on the valley floor which are quite fragile. Modification of the lake perimeter due to the digging of irrigation channels and the threat of modified spring flows because of geothermal development, prompted action by the FWS under the ESA. The lake is now owned by the Nature Conservancy, so water diversions for agriculture have ceased. There is interest in geothermal development within two kilometers of Borax Lake, and the possibility that this development could reduce thermal spring inflows to the lake, cooling lake temperatures and making them more conducive for the survival of non-native fish that would out-compete the Borax Lake Chub. The Nature Conservancy, Service, ODFW, and BLM have been working since 1983 to protect, maintain, and enhance habitat for Borax Lake chub.

Conservation Needs
Recovery objectives listed in the recovery plan (USFWS 1987) include further protection of the Borax Lake ecosystem, reestablishment of habitats, and removal of threats to the ecosystem.


Hutton Spring tui chub (Gila bicolor ssp.): (The following life history information is taken from 50FR12302, 3/28/85; and USFWS Recovery Plan, 1998c).

The Hutton Spring tui chub is listed as threatened (50FR12302, 3/28/85) but critical habitat has not been designated.

A small to medium sized minnow, the Hutton Spring tui chub is only found in Hutton Spring in Lake County, south-central Oregon. Although Hutton tui chub have also been reported from a second unnamed spring, their existence within this second spring system is questionable since they were not located during 1996 surveys (USFWS 1998c).
Little information is known regarding the ecology of the Hutton tui chub other than dense aquatic algae is apparently needed for spawning and rearing of young. Preferred habitat conditions for Hutton Spring tui chub may be inferred from research on the tui chub from the Upper Klamath basin which showed a thermal mean maximum of 32.2 + -0.2°C. and a DO mean minimum of 0.59 + 0.04 mg/l (Castleberry & Cech 1993). These figures should be considered only as guidance since the most sensitive life stage may not have been tested and the relative sensitivity of tui chub stocks from these geographically separate areas is unknown. Additionally, the fact that Klamath tui chub are adapted to a much more variable habitat than that of the Hutton Springs tui chub may lessen the comparability of these values.

Examination of gut contents from Hutton tui chub showed this fish to be omnivorous with a majority of food eaten being filamentous algae, although they have been observed feeding on terrestrial insects. It appears that dense aquatic algae are needed for spawning and rearing of young.

Threats
Although the habitat quality of the primary spring is well maintained, the reasons for listing as threatened include: extremely limited distribution in a water sparse area; naturally low population numbers (450, estimate); vulnerability to introductions of exotic species; and threat of contamination from a toxic waste dump along the southwest shore of Alkali Lake (50FR12302, 3/28/85). Hutton Spring is fenced from livestock, however, the second spring is vulnerable to damage by livestock and human activities. Occurring on private land, the Hutton tui chub is threatened by actual or potential modification of its habitat.

Conservation Needs
Objectives listed in the Recovery Plan for the Rare and Native Fishes of the Warner and Alkali Subbasin (USFWS 1998) include: 1) long-term protection of habitat; 2) development and implementation of long-term habitat management guidelines to ensure the continued persistence of important habitat features, including monitoring of current habitat and investigation for an evaluation of new spring habitats; and 3) research into life history, genetics, population trends, habitat use and preference, and other important parameters to assist in further developing long-term protection guidelines.


Lost River sucker (Deltistes luxatus) and Shortnose sucker (Chasmistes brevirostris): (The following life history information is taken from USFWS Recovery Plan 1993).

Lost River and shortnose suckers were listed as endangered under the ESA in 1988 (53FR27130). Critical habitat was proposed in 1994 (59FR61754) and is described in Table 2.

The Lost River and shortnose suckers are endemic to the upper Klamath Basin, with the largest populations occurring in Upper Klamath Lake in Oregon and Clear Lake Reservoir in California. Both species have a variable head morphology, especially the shortnose sucker, which makes identification difficult. Identification is further frustrated by a close relationship between the shortnose sucker and the Klamath largescale sucker, Catostomus snyderi. All three suckers primarily reside in lakes and reservoirs; however, the Klamath largescale sucker also has stream-resident populations. Problems with correct identification has made accurate determination of sucker distributions, especially for juvenile fish, difficult.

The Lost River sucker is one of the largest sucker species and may grow to one meter in total length. Shortnose suckers are usually less than 50 cm long. Lost River suckers are bottom feeders primarily eating midge larvae; shortnose suckers feed mostly on zooplankton, especially Daphnia. Both midges and Daphnia are extremely abundant in Upper Klamath Lake.

Age and Growth. Lost River suckers have been aged up to 43 years old. Sexual maturity occurs between the ages of 6 to 14 years with most mature by age 9. Shortnose suckers have been aged at up to 33 years. Sexual maturity appears to be between 5 and 8 years with most maturing between age 6 and 7.

Spawning Habitat. Both species primarily reside in lakes but spawn in tributary streams and rivers. However, in Upper Klamath Lake both species have stocks that spawn in springs located in the lake. Suckers begin their spawning migration from February to early March. Water temperatures range from 5.5 to 19°C. Lost River and shortnose suckers spawn near the bottom and, when gravel is available, eggs are dispersed within the top several centimeters. When spawning occurs over cobble and armored substrate, eggs fall between crevices or are swept downstream.

Habitat. Larval and juvenile Lost River and shortnose suckers usually spend relatively little time in tributary streams and migrate back to the lake shortly after swim-up stage. The majority of suckers emigrate during a six-week period starting in early May. It appears that most larval emigration for both species occurs during the night and twilight hours. During the day, the larvae typically move to shallow shoreline areas in the river. Higher densities of larval suckers seem to occur along vegetated shores and in pockets of open water surrounded by emergent vegetation. Larvae seem to avoid areas devoid of emergent vegetation. A strong shoreline orientation is displayed by sucker larvae, they use areas such as marsh edges for nursery habitat. After emigrating from the parental spawning sites in late spring, larval and juvenile Lost River and shortnose suckers inhabit near shore waters (mostly under 50 cm depth) throughout the summer months. In Upper Klamath Lake, juvenile suckers are mostly found in areas of the lake with dissolved oxygen concentrations >4 mg/l. Few sites in the lake had juvenile suckers where pH values were 9.0 or higher.

During summer, much of the Upper Klamath Lake can be stressful or lethal to fish owing to low levels of dissolved oxygen, and high temperatures, pH, and unionized ammonia. Under such conditions, suckers attempt to avoid the worst areas. Water quality in the northwest lobe of Upper Klamath Lake generally remains good owing to input of spring water in the area of Pelican Bay. Suckers tend to aggregate in this region apparently to avoid lethal conditions elsewhere in the lake. Nonetheless, in some years large numbers of suckers are killed as a result of poor water quality and outbreaks of “Columnaris” bacterial infections. Mortality of large numbers of Lost River suckers and some shortnose suckers coincided with high water temperatures, low DO, and high pH during 1986 in Upper Klamath Lake (Scoppettone 1986). Other incidents of sucker die-offs are also reported by USBR (1997). High concentrations of unionized ammonia also occur during periods of poor water quality in Upper Klamath Lake.

Laboratory-performed tolerance tests on these fish indicate that ambient summertime water quality conditions in the Upper Klamath Basin can be acutely toxic to juvenile suckers (Monda and Saiki 1993). Results (LC-50 values) of 96-hour bioassays with Lost River and shortnose suckers were presented in U.S. Bureau of Reclamation’s (USBR) 1997 draft biological report and are summarized below. To provide a conservative estimate of acute toxicity, USBR presented the results as the lower 95% confidence interval.

NH3-N(mg/l) pH DO(mg/l) Temp.(C)

LR sucker larvae 0.43 9.77 2.0 30.5
juveniles 0.34 10.1 2.0 29.9

SN sucker larvae 0.73 10.01 2.4 31.2
juveniles 0.14 9.76 2.4 27.8


Using adult Lost River suckers, the LC-50 for DO was determined at 2.8 mg/l. In other research, the critical thermal maximum (where fish could no longer maintain equilibrium) determined for shortnose sucker adults was 32.7 + 0.1°C (Castleberry and Cech 1993).

Threats
Habitat degradation from agricultural practices and grazing can cause loss of critical riparian areas and increases in nutrient input to the lake. Increased nutrients leads to increased primary production and consequent increases in pH (Kann, Klamath Tribes, EPA pers. comm., 1998). The Bureau of Reclamation operates the lake and has initiated some riparian restoration and associated research projects, although restoration work is in early stages. Water depth is a key factor in separating surface-dwelling sucker larvae from benthic fathead minnows that would prey on them (USBR 1997).

Conservation Needs
The outline for recovery actions listed in the recovery plan (USFWS 1993) includes the following: 1) conserve genetic diversity of populations; 2) examine and enhance populations; and 3) rehabilitate watershed conditions to improve lake and river habitats. Included under the third action is improvement of water quality with the development of water quality goals using existing and new data.


Warner sucker (Catostomus warnerensis): (The following life history information is taken from ODFW (1996), Species at Risk; and USFWS Recovery Plan 1998c).

The threatened status for the Warner sucker was published on September 27, 1985 (50FR39117). Critical habitat is designated (50FR39122) and includes: sections of Twelvemile and Twentymile Creeks; Spillway Canal north of Hart Lake; Snyder and Honey Creeks (Table 2).

When adequate water is present, Warner suckers may inhabit all the lakes, sloughs, and potholes in the Warner Valley. While most of the Warner Basin lies in Oregon, small portions extend into California and Nevada. The Warner Basin provides two generally continuous aquatic habitat types; a temporally more stable stream environment, and a temporally less stable lake environment.

A common phenomenon among fishes is phenotypic plasticity induced by changes in environmental factors, which is exhibited in the life history of the Warner sucker. The lake and stream morphs of the Warner sucker probably evolved with frequent migration and gene exchange between them. The larger, presumably longer-lived, lake morphs are capable of surviving through several continuous years of isolation from stream spawning habitats due to drought or other factors. Stream morphs serve as sources for recolonization of lake habitats in wet years following droughts, such as occurred in the refilling of Warner Lakes in 1993 following their desiccation in 1992. Lake morph Warner suckers occupy the lakes and, possibly, deep areas in the low elevation creeks, reservoirs, sloughs and canals.

Age and Growth. Lake morph suckers are generally much larger than steam morphs, however, growth rates in either habitat are not well studied. Sexual maturity is believed to usually occur at an age of 3-4 years.

Feeding. The feeding habits of the Warner sucker depend to a large degree on habitat and life history stage, with adult suckers becoming less specialized than juveniles and young-of-the-year (YOY). Larvae have terminal mouths and short digestive tracts, enabling them to feed selectively in mid-water or on the surface. Invertebrates, particularly planktonic crustaceans, make up most of their diet. As the suckers grow, they gradually become generalized benthic feeders. Adult stream morph suckers forage nocturnally over a wide variety of substrates. Adult lake morphs are thought to have a similar diet, though food is taken over predominantly muddy substrates.

Spawning Habitat. Spawning usually occurs in April and May. Temperature and flow cues appear to trigger spawning, with most spawning taking place at 14-20°C when stream flows are relatively high. Warner suckers spawn in sand, or gravel beds in pools. Warm, constant temperature source springs located in the upper Honey Creek drainage and the tributary Snyder Creek, are possible important spawning habitats and sources of recruitment for lake recolonization. In years when access to stream spawning areas is limited by low flow or by physical in-stream blockages (such as beaver dams), suckers may attempt to spawn on gravel beds along the lake shorelines.

Larval and YOY Habitat. Larvae generally occupy shallow backwater pools or stream margins with abundant macrophytes, where there is little or no current. Larvae venture near higher flows during the daytime to feed on planktonic organisms but avoid the mid-channel water current at night. Spawning habitat may also be used for rearing during the first few months of life because when young eventually become immersed in high stream flows they do not appear to drift large distances downstream; i.e., the YOY remain in spawning habitat areas. YOY are often found over deep, still water from mid-water to the surface, but also move into faster flowing areas near the heads of pools. For both runs and pools, YOY usually occupy quiet water close to shore.

Juvenile and Adult Habitat. Both juveniles and adults prefer areas of the streams which are protected from the main flow, seeking out deep pools. Beaver ponds may offer important refugia. Preferred pools tend to have: undercut banks; large beds of aquatic macrophytes; root wads or boulders; a surface to bottom temperature differential of at least 2°C. (at low flows); maximum depth greater than 1.5 meters; and overhanging vegetation (often Salix ssp). Although suckers may be found almost anywhere in calmer sections of streams, the fish typically will not be far from larger pools (approximately 1/4 mile up- or down- steam).

When submersed and floating vascular macrophytes are present, they often form a major component of sucker-inhabited pools, providing cover and harboring planktonic crustaceans which make up most of the YOY sucker diet. Rock substrates are important in providing surfaces for epilitihic organisms upon which adult stream morph suckers feed, and finer gravel or sand are used for spawning. Substrate embeddedness (e.g., from silt) has been negatively correlated with total sucker density.

Habitat use by lake morph suckers appears similar to that of stream morph suckers in that adult suckers are generally found in the deepest available water where food and cover are plentiful. Deep water also provides refuge from avian predators.

By day, juveniles and adult suckers take shelter in the deepest available water and/or undercut banks. Deep pools also allow suckers to mitigate temperature extremes by moving vertically in the water column. With the absence of aquatic macrophytes, suckers can be seen schooling near the bottoms of these deep pools during the day. At night they disperse thorough various habitat types and water depths to forage for food.

Exact temperature, dissolved oxygen, or pH requirements for the Warner sucker are unknown. These fish co-occur with redband trout and, therefore, require cooler water temperatures.

Threats
The loss of either lake or stream morphs to drought, winter kill, excessive flows and a flushing of the fish in a stream, in conjunction with the lack of safe migration routes and the presence of predaceous game fishes (such as crappie), may strain the ability of the species to rebound. Irrigation diversions have also reduced available habitat and blocked migration (USFWS Recovery Plan 1998c).

Conservation Needs
The objectives outlined in the recovery plan (USFWS1998c) include protection and rehabilitation of populations and habitat, conservation of genetic diversity of the populations, controlling introduced exotic fishes, securing adequate water supplies, monitoring populations and habitat conditions and evaluation of long-term effects of climatic trends on the recovery.


Foskett speckled dace (Rhinichthys osculus ssp): (The following life history information is taken from ODFW (1996), Species at Risk; and USFWS Recovery Plan 1998c).

The Foskett speckled dace was listed as threatened on March 3, 1985 (50FR12302). No critical habitat has been designated.

The Foskett speckled dace occurs in Foskett Spring and nearby Dace Spring, small springs in the Coleman Basin on the east side of the Warner Valley, Lake County, south-central Oregon. This is an arid region with approximately eight inches of annual precipitation. Numbers of this species are estimated at 27,000 (USFWS 1998c). The majority of these individuals are found in temporally unstable habitat.

Very little is known about the biology/ecology of the Foskett speckled dace. The only habitat information available regards plant species found around the springs. These include rushes, sedges, Mimulus, Kentucky bluegrass, thistle and saltgrass. Foskett Spring is a cool water spring with a constant temperature regime of 18°C (Munhall, USBLM, EPA pers. com., 5/20/989). BLM monitoring of spring water during the mid-1980s revealed a pH range of 7.2-8.1 and a hardness range of 32.6-48.7 mg/l as CaCO₃ (Munhall, USBLM, EPA pers. comm., 5/20/98). No information is available on growth rates, age of reproduction or behavioral patterns of Foskett speckled dace.

For speckled dace (not from Foskett spring; life stage/age unknown), the thermal mean maximum was experimentally determined to be 32.4 + -0.6°C., and the mean minimum DO to be 0.8 + -0.06 mg/l (Castleberry and Cech 1993).

Threats
Occurring on private land at the time of ESA listing, this dace species was threatened by actual or potential modification of its habitat. Through a land exchange, the BLM acquired Foskett Spring in 1986 and has since fenced the spring from livestock. However, water flow and indirect pollution/runoff is still a concern. These fish have extremely limited distributions, occur in low numbers naturally, and inhabit springs that are susceptible to human disturbance. Factors that threaten the species include: groundwater pumping for irrigation, geothermal development in the area, excessive trampling of the habitats by livestock, channeling of the springs for agricultural purposes, and other mechanical manipulation of the spring habitats.


Conservation Needs
The actions necessary for the recovery of the Foskett speckled dace are the same as listed for the Hutton tui chub.


Vernal Pool Fairy Shrimp (Branchinecta lynchi): (The following life history information is taken from 59FR48135, 9/19/94; and EPA (1997) Region 9 Biological Evaluation for the California Toxics Rule).

On September 19, 1994, the FWS published a final rule listing the vernal pool fairy shrimp as threatened in its known habitats (all in California at the time). Region 10 EPA received a FWS letter dated April 8, 1998, noting the discovery of the threatened fairy shrimp in vernal pools in southwestern Oregon. As indicated in the letter, the shrimp inhabit several vernal pools in an area known as the Agate Desert, near Medford and White City, Jackson County, Oregon.

The vernal pool fairy shrimp are members of the aquatic crustacean order Anostraca. These branchiopods which range up to an inch in length, are endemic to vernal pools, an ephemeral freshwater habitat. The shrimp are not known to occur in riverine waters, marine waters, or other permanent bodies of water. They are ecologically dependent on seasonal fluctuations in their habitat, such as absence or presence of water during specific times of the year, duration of inundation, and other environmental factors that include specific salinity, conductivity, dissolved solids, and pH levels. Water chemistry is one of the most important factors in determining the distribution of fairy shrimp. The shrimp are sporadic in their distribution, often inhabiting only one or a few pools in otherwise more widespread vernal pool complexes. Populations of these animals are defined by pool complexes rather than by individual vernal pools. In California, the majority of known populations inhabit vernal pools with clear to tea-colored water, most commonly in grass or mud bottomed swales, or basalt flow depression pools in unplowed grasslands. The water in pools inhabited by this species has low TDS, conductivity, alkalinity, and chloride.

Fairy shrimp feed on algae, bacteria, protozoa, rotifers, and bits of detritus. Females carry fertilized eggs that are either dropped to the pool bottom or remain in the brood sac until the female dies and sinks. The “resting” or “summer” eggs are capable of withstanding heat, cold, and prolonged desiccation. When the pools refill in the same or subsequent seasons some, but not all, of the eggs may hatch. The egg bank in the soil may be comprised of the eggs from several years of breeding. The early stages of the fairy shrimp develop rapidly into adults. These non-dormant populations often disappear early in the season, long before the vernal pools dry up.
The primary historical dispersal method for the fairy shrimp likely was large-scale flooding, resulting from winter and spring rains, which allowed the animals to colonize different individual vernal pools and other vernal pool complexes. Waterfowl and shorebirds likely are now the primary dispersal agents for fairy shrimp. Vernal pools form in regions with mediterranean climates where shallow depressions fill with water during fall and winter rains and then evaporate in the spring. In the Agate Desert area of Oregon, vernal pools form on a hardpan surface during the spring.

Threats
Habitat of these animals is imperiled by a variety of human-caused activities, primarily urban development, water supply/flood control activities, and conversion of land to agricultural use. By virtue of the small isolated nature of many of the remaining populations, the stochastic (random) threat of extinction exists for these shrimp. In Oregon, the main threat is habitat loss due to development.

Conservation Needs
The final rule (59FR48136) states the conclusion of six fairy shrimp specialists, preservation of extant habitat and its associated community as necessary for protection of these animals. A recovery plan is under development.


Oregon Spotted Frog (Rana pretiosa) and Columbia Spotted Frog (Rana luteiventris): (The following life history information is taken from Hayes 1994, 1997; ODFW 1996; Richter 1995; Richter and Azous 1995; and WDFW 1997).

The Oregon spotted and Columbia spotted frogs are currently listed as candidate species under ESA. Under a proposed rule on 9/19/97 (62FR49397), the FWS issued a “warranted but precluded” finding in Oregon.

After specific information on each species, general life history information is presented; most research has been on the Oregon spotted frog.

Distribution (Hayes 1994). The spotted frog, characterized as a highly aquatic species, has a relatively broad geographic range from northeastern California northward through most of Oregon, Washington, and British Columbia, into the Alaskan panhandle, and eastward through northern Nevada, northern Utah, most of Idaho, western Wyoming, western Montana, and the western edge of Alberta. This view of the geographic distribution ignores unrecognized taxonomic units “within” the spotted frog.

The most recent data indicate that the Oregon spotted frog is known from 24 sites across three entities, 1 in British Columbia, 20 in Oregon, and 3 in Washington (Hayes 1997). These sites represent the headwatermost locations of suitable habitat in the drainages in which they exist and those with the least altered habitat and fewest exotic predators among historical sites. The Oregon spotted frog is extant in two protected but vulnerable areas in the Willamette hydrographic basin, Penn Lake and Gold Lake Bog, and in the Deschutes and Klamath Basins.

Important habitat for the Oregon spotted frog is at elevations below about 5,300 feet. This distribution is latitude dependent with the frog found below 600 meters in southern Washington and below about 1,500-1,600 meters in southern Oregon. Spotted frogs inhabit marshy pond or lake edges, or algae-covered overflow pools of streams (not the streams themselves) and probably require a freshwater spring for overwintering. Food consists of insects, mollusks, crustaceans, and arachnids.

The Columbia spotted frog’s habitat in Oregon is at elevations of approximately 4,000 feet or higher; generally in the drier, east-side Cascades and higher plateau inland habitats. The Columbia spotted frog is marsh dwelling and, at times, is also found in streams. There may be a dependancy on a nearby spring.

Reproduction (Hayes 1994). The spotted frog is generally inactive during the winter season, although some individuals may be observed at the water surface on the few relatively warmer days. Emergence from overwintering sites begins as early in the year as the winter thaw allows. In southwestern British Columbia and the Puget Sound region, emergence takes place from late February to mid-March. Emergence dates are lacking for Oregon, but historical records indicate that Oregon spotted frogs were detected on the Willamette Valley floor as early as 8 February. A night-time water temperature measurement of 10.6°C suggests that even early in the active season, the Oregon spotted frog has been found in relatively “warm” water (Hayes 1994)

Male Oregon spotted frogs arrive at breeding sites several days before the first females appear. Breeding sites are located in the shallow (5-15 cm) portions of marshes or ponds or the overflow areas of streams, typically disconnected from the main body of water. Adult males aggregate in small calling groups and call while floating with their heads at the water surface or while sitting above water on mats of vegetation. Females appear at breeding sites from a few days to over a week after the males. When receptive, females approach male calling groups, gain amplexus with a male, and then deposit eggs in a few inches of water (typically during March-April). The globular egg masses contain several hundred to several thousand eggs. It’s likely that the dates of oviposition vary considerably between years because local climatic conditions may affect when water temperatures reach the range suitable for egg laying. Oregon spotted frog embryos have lethal thermal limits of 6°C and 28°C; average water temperature near the egg masses of is 20.7°C over the interval before hatching.

Spotted frogs exhibit “communal” laying. Masses are deposited unattached, often in water so shallow that only the lower half of each egg mass is submerged, the upper portion being exposed directly to the air. This pattern of oviposition makes mortality of embryos from desiccation (drying) or freezing, relatively frequent; up to 30 percent is not unusual. Ovipositing sites may be reused in successive years, indicating unique characteristics, limited sites, limited flexibility of adults to switch sites, or combinations thereof. This site-dependancy may make the spotted frog particularly vulnerable to oviposition-site modification.

Data on the developmental schedule in Oregon are lacking, but it is anticipated to be somewhat faster at the lower latitude (given a roughly equivalent elevation) than that observed in British Columbia where larvae can hatch in 5-10 days, develop to metamorphosis in 5-7 months, and reach sexual maturity in two (males) to three (females) years following metamorphosis.

Habitat Requirements (Hayes 1994).
The single feature that united all verifiable spotted frog localities in western Oregon for which habitat data could be retrieved, was that each site had a marsh or bog. Moreover, these marshes frequently represented overflow areas of a nearby river or stream.

Observations in Oregon over the past two years strongly suggest that postmetamorphic Oregon spotted frogs are somehow tied to warmer water (20-35°C; average 28.6°C) during the late spring and summer season when frogs are active. Water temperature must be >20°C for three months. Although Hayes documented a warm water preference for Oregon spotted frogs, Oregon spotted frogs in western Washington were found active in water consistently <10°C (50°F) and frogs were found active under ice (including a pair in amplexus) where the water temperature was -0.5°C (31°F) [WDFW 1997]. Unlike the Oregon spotted frog, the Columbia spotted frog is not a warm water specialist.

Water Quality (not spotted frog specific) (Richter 1995).
Amphibians are found in water of widely varying chemical composition. Researchers have generally found water chemistry to not directly limit amphibian distribution and breeding. However, a significant negative correlation exists between amphibian richness and water column conductivity (Azous 1991, in Richter 1995). Moreover, Platin (1994) and Platin and Richter (1995, in Richter 1995) found Rana aurora (a red-legged frog) embryo mortality positively correlated to a principal water quality component comprised of conductivity, Ca, Mg, and pH, and negatively correlated to a second principal component including total P, total suspended solids, Pb, Zn, Al, total organic content, and dissolved oxygen. Interestingly, Ambystoma gracile (a Northwest salamander) egg mortality under similar conditions was uncorrelated to either of these two principal components but rather correlated to total petroleum hydrocarbons and fecal coliforms.

Threats
Extirpation from much of the former range for both species coincides with introduction and spread of the highly carnivorous bullfrogs and exotic predatory fish such as bass. Brook trout, the only exotic macropredator present in Penn Lake, has had a significant impact on Oregon spotted frog populations. Substantially greater areas and habitat complexity found at Gold Lake Bog may allow the relatively large Oregon spotted frog population to co-exist with brook trout. However, during drought conditions, Oregon spotted frog life stages may be placed in closer proximity to brook trout. The opportunity for recolonization is nil due to the isolated nature of these Oregon spotted frog populations. (Hayes, Portland State University, EPA pers. comm., 1997). In conjunction with these impacts, poor water quality may limit spotted frog distribution.

Conservation Needs
In order to manage for conservation of these spotted frogs, understanding of certain aspects of the life history and impacts need to be strengthened including: precise location of overwintering sites; influence of different exotic species; successional dynamic between marsh habitat loss and creation; livestock effects; drought condition interaction with other factors especially exotic aquatic predators; and movement.


Critical Habitat
Of those species addressed within this biological opinion, Federally designated critical habitat has been delineated for Borax Lake chub and Warner sucker and proposed for Lost River and shortnose suckers. Table 2 briefly summarizes a description of each species’ critical habitat. Critical habitat for the Warner sucker identifies temperature and dissolved oxygen as important components of the critical habitat and the 50 foot riparian area included on either side of the stream bank is intended to maintain suitable conditions for these parameters. For the Lost River and shortnose suckers, general water quality is identified as a primary constituent element.


Table 2. Description of Critical Habitat for those species addressed within this biological opinion.

Listed Species	Fed.Reg. Notice	Description of Critical Habitat
Borax Lake chub	10/02/92 47FR43960	Borax Lake and the aquatic environments associated with its outflow.
Warner sucker	09/27/85 50FR39122	In Lake County, portions of Twelvemile Creek, Twentymile Creek, the spillway canal north of Hart Lake, Snyder Creek, and Honey Creek and 50 feet on either side of the stream banks.
Lost River and Shortnose suckers*	12/01/94 59FR61754	Clear Lake reservoir and major tributaries Link and Klamath rivers downstream to Iron Gate Dam Upper Klamath Lake and major tributaries lower Williamson River, and Sprague River to near Bly Gerber Reservoir and major tributaries Primary Constituent Elements - sufficient quantity and quality of water - areas inhabitable for use in feeding, spawning, nursery, rearing, migration - physical habitat, and biological components of food supply , natural scheme of predation, parasitism and competition

* proposed critical habitat

In evaluating the effects of the action on critical habitat, the FWS concluded that the water quality parameters considered in this consultation are an integral part of all these species habitats. Analysis of effects to the species relates directly to their habitats and, therefore, critical habitat analysis is encompassed within the evaluation.


ENVIRONMENTAL BASELINE
Environmental baseline is defined as the past and present impacts of all Federal, State, or private actions and other human activities in an action area. Current water quality conditions and standards are discussed below, although past conditions and standards have contributed to the environmental baseline.

Action Area
Many of the species covered in this BO are wholly contained within the action area (the state of Oregon), although there are some species whose range crosses over the Oregon boundaries into other states. The current status of the species within the action area is presented above, under the previous section.


Current Water Quality Conditions
According to Oregon’s 1998 draft 303(d) list, 13,796 stream miles are identified as water quality limited. Table 3 displays the number of stream miles for various standards included in the 1998 303(d) list.

Table 3. Stream miles with various water quality limitations from the 1998 303(d) list.

Stream Miles	Standard Limitation
12,146	temperature
1,130	dissolved oxygen
1,117	pH
2,172	habitat modification
1,426	sediment impairment
1,624	flow modification

Of the systems reviewed by the state for temperature impairment, 930 waterbody segments are listed for temperature, 542 require additional data or are of potential concern, and 559 segments were meeting the temperature standard.

As taken from EPA’s biological assessment (Quigley et al. 1997), human activities have resulted in the simplification of habitat and a reduction in aquatic system quality in the majority of river basins within the Pacific Northwest. Habitat simplification and decreased quality leads to a decrease in the health and diversity of anadromous salmonid populations. The composition, distribution, and status of fish are different than they were historically. Habitat loss, fragmentation and isolation may place remaining populations at risk.


Water Quality Standards
The standard revisions described within this biological opinion were adopted by the State of Oregon on January 11, 1996, with the effective date of March 1, 1996, for DO and pH and July 1, 1996, for temperature. Oregon submitted the revised water quality standards to EPA for approval on July 11, 1996. Thus, these standards have been in effect for over 3 years.

If EPA determines that any such revised or new water quality standard is not consistent with applicable requirements, EPA is required to specify the disapproved portions and the changes needed to meet the requirements. The state is then given an opportunity to make appropriate changes, but if the state does not adopt the required changes, EPA must promulgate federal regulations to replace those disapproved portions. Until such changes are made, either by the state or EPA, standards adopted by the state are in effect. Although Oregon’s standards will not revert to former water quality standards, these earlier standards have contributed to the condition of the environment and the status of the species considered in the BO.

Waters which do not meet the water quality standards are considered “water quality limited” and are included on the state’s 303(d) list. For each of these waters on the list, ODEQ is required to develop a total maximum daily load (TMDL). Attainment of the TMDL is intended to lead to attainment of the applicable water quality standard for that waterbody. ODEQ has recently finalized the 1998 303(d) list and submitted to EPA a schedule for completing TMDLs by the year 2007. In developing the schedule, ODEQ prioritized subbasins with spawning and rearing habitat of Federally listed threatened and endangered fish species, with second priority going to subbasins with candidate or proposed species.

For the purposes of this consultation, we are assuming that these water quality criteria will be met. In order for waters to meet these criteria, it must be further assumed that TMDLs will be implemented. Actions included in TMDLs will likely take considerable time to be reflected in numeric standard compliance, but until that time there will be a gradual movement in that direction. Consequently, we predict that water quality within the state will improve overall and more significantly within those segments where TMDLs are actively being implemented.


EFFECTS OF THE ACTION

Dissolved Oxygen Standard
Bull trout and Lahontan cutthroat trout
Three different standards apply to waters inhabited by these two trout species; salmonid spawning; cold water aquatic life; and cool water aquatic life. The salmonid spawning criteria has two components, one applicable to surface waters and one to intergravel dissolved oxygen (IGDO). Consequently, EPA has made three determinations based upon components of these DO standards: salmonid spawning water column; salmonid spawning IGDO; and cool water aquatic life. Determinations made by EPA for both salmonid spawning water column and the cool water aquatic life standards are not likely to adversely affect, while for the salmonid spawning IGDO standard EPA has made a likely to adversely affect determination.

EPA’s determination of not likely to adversely affect for bull trout and Lahontan cutthroat trout for salmonid spawning water column DO criteria is based upon comparison of Oregon’s criteria with EPA’s water quality criteria guidance (EPA 1986). EPA’s guidance for dissolved oxygen comes from their Ambient Water Quality Criteria for Dissolved Oxygen (1986) in which they reviewed a sizable body of literature on oxygen requirements of freshwater aquatic life. The guidance recommends a water column DO of 11 mg/l for no production impairment, 9 mg/l for slight production impairment, and 8 mg/l for moderate production impairment. Oregon’s 11 mg/l DO concentrations of the salmonid spawning criterion correspond to EPA’s highest defined level of protection.

EPA has determined that the IGDO criterion of 6 mg/l is likely to adversely affect bull trout and Lahontan cutthroat trout. This determination is based upon several studies which show that adverse effects on survival of embryos and juvenile salmonids begin to occur at IGDOs of less than 8 mg/l (Hollender 1981, Phillips and Campbell 1962, and Sowden and Power 1985, as cited in ODEQ 1995). In addition, reduction in the IGDO from saturation appears to affect growth, which could in turn affect survival. Fry survival in their natural environment may be related to the size of the fry at hatch (ODEQ 1995) in that they can be outcompeted by larger individuals and are more susceptible to predation, disease, starvation or a combination thereof (Mason 1969; Chapman and McLeod 1987).

Interpreting the effects of dissolved oxygen levels to endangered species provides some challenges. Effects of dissolved oxygen levels on early life stages of salmonids are strongly influenced by water velocity, as presented in the ODEQ issue paper (1995). In addition, the FWS recognizes that these laboratory studies used in interpreting the effects, generally have controlled conditions with minor variations in oxygen concentrations, in contrast to the natural environment where dissolved oxygen concentrations in the water exhibit considerable variation.

For areas with federally listed aquatic species, ODEQ has committed to using a concentration of 8 mg/l IGDO as the listing criterion for the 303(d) list of water quality limited streams (Attachment 3). Once a stream is on the list, a TMDL will be developed which will put in place management actions to increase dissolved oxygen levels within the stream. With the State of Oregon’s commitment to use 8 mg/l as the listing level, we believe that the IGDO is not likely to adversely affect Lahonton cutthroat trout or bull trout.

For the proposed cool water criterion (6.5 mg/l absolute minimum), EPA made a not likely to adversely affect determination for both bull trout and Lahonton cutthroat trout. The BA indicates that cool water criteria would apply only when salmonid spawning is not occurring. Therefore, the time period when cool water criteria applies is encompassed in various time intervals spanning from July 1 - February 30, depending upon which basin the trout inhabits (Attachment 1).

According to the BA and the supplemental ODEQ letter (Attachment 1), bull trout spawning periods would not be entirely covered under the time periods specified for application of salmon spawning dissolved oxygen criteria. Table 4 compares the applicable DO criterion with general bull trout spawning times in Oregon basins. Most bull trout populations in Oregon spawn in September and October, although bull trout populations may begin spawning in July in the Metolius River basin (Bellerud et al. 1997) and in August in the Grande Ronde (Buchanan et al. 1997) and in the Klamath Basins (Klamath Basin Bull Trout Working Group, unpublished data) . In those basins where spawning DO criteria apply during the fall, the onset date is October 1 with the exception of the Deschutes River and westside tributaries which is September 1. As indicated in Table 4, the entire bull trout spawning period would not be covered by the most protective DO criterion in several basins. During this time the coldwater (8.0 mg/l) or coolwater (6.5 mg/l) criteria would apply. In the Malheur, Powder, and Klamath Basins, there is no overlap of bull trout spawning and application of salmonid spawning DO criterion. In the Klamath Basin, cold water aquatic life criteria apply during the spawning period, while in the Malheur and Powder Basins cool water aquatic life criterion apply during spawning.

Table 4. Comparison of applicable dissolved oxygen criteria to general spawning periods in basins designated for bull trout beneficial use.

Basin	Applicable DO standards	Bull trout spawning periods
Deschutes River & Eastside tributaries	10/1-6/30 11mg/l surface, 6.0 mg/l IGDO 7/1-9/30 8 mg/l	September-October3
Deschutes River & Westside tributaries	9/1-6/30 11mg/l surface, 6.0 mg/l IGDO 7/1-8/31 8 mg/l	July - October1
Malheur River	3/1-6/30 11mg/l surface, 6.0 mg/l IGDO 7/1-2/30 6.5 mg/l	September-October3
Grande Ronde	10/1-6/30 11mg/l surface, 6.0 mg/l IGDO 7/1-9/30 6.5 mg/l or 8.0 mg/l	end of August - October1
Powder	3/1-6/30 11mg/l surface, 6.0 mg/l IGDO 7/1-2/29 6.5 mg/l	September-October3
Klamath	3/1-6/30 11mg/l surface, 6.0 mg/l IGDO 7/1-2/29 8.0 mg/l	mid August2 - mid November1
Willamette	10/1-5/31 11mg/l surface, 6.0 mg/l IGDO 6/1-9/30 8.0 mg/l	early September - early October1
John Day	10/1-6/30 11mg/l surface, 6.0 mg/l IGDO 7/1-8/31 8.0 mg/l 9/1-9/31 6.5 mg/l	September-October3
Umatilla	10/1-6/30 11mg/l surface, 6.0 mg/l IGDO 7/1-9/30 6.5 mg/l	mid September - early October1
Walla Walla	10/1-6/30 11mg/l surface, 6.0 mg/l IGDO 7/1-9/30 6.5 mg/l	early to mid September - October1

¹ Buchanan et al. 1997.
² Klamath Basin Bull Trout Working Group, unpublished data
³ Pratt 1992, general spawning times for bull trout- not basin specific


Critical dissolved oxygen levels for developing salmonid embryos occur in the intergravels surrounding the eggs. IGDO varies depending on several interrelated factors including surface water concentrations, percentage of fine sediment in the gravel pores, sediment oxygen demand, and the oxygen demand of the eggs. In addition, the critical level of DO is dependent upon the velocity of water past the eggs; less oxygen is needed at higher velocities (ODEQ 1995). EPA recommends that application of dissolved oxygen criteria assume a loss of at least 3 mg/l from surface water to the intergravels, although actual losses from surface to IGDO vary widely both in location and time (ODEQ 1995). For streams with a cold water criterion of 8 mg/l, a 3 mg/l loss from surface to intergravels would equate to a DO concentration of 5 mg/l. There is abundant evidence within ODEQ’s issue paper (1995) indicating that deleterious effects to young life stages of salmonids occur at DO concentrations even above 5 mg/l. For streams where cool water criterion apply, this loss would mean an intergravel concentration that is very low and likely to have significant adverse effects on the young life stages of bull trout. Based upon this information, we do not concur with EPA’s determination of not likely to adversely affect for bull trout.

Most of the early life stages of Lahontan cutthroat trout, which are recognized as being the most sensitive and requiring relatively high dissolved oxygen concentrations, would be covered by the salmonid spawning DO criterion. Spawning criteria in Malheur and Owyhee Basins apply from March 1 thru June 30, overlapping much of the LCT spawning which occurs from April thru July (USFWS 1995). Eggs generally hatch in 4 to 6 weeks and fry emerge 2-3 weeks later. Eggs of late spawners may be exposed to the lower dissolved oxygen levels when cool water criterion apply, from July 1 thru February 29. The measure of 6.5 mg/l for the cool water criterion is measured for surface water as the absolute minimum. Eggs will be in the intergravels and exposed to lower DO levels (3.5 mg/l), assuming a 3.0 mg/l decrease from surface water to intergravels. As noted above, IGDO levels below 8 mg/l have shown detrimental effects to salmonid early life stages. With the criterion measurement unit as an absolute minimum, diurnal and seasonal fluctuations will increase DO levels above the minimum for most of the year. However, minimum DO concentration would likely be experienced when stream temperatures are the highest (July and August), because warm water holds less oxygen in solution than cold water (Gordon et al. 1992), overlapping with egg development of late spawners.

The cool water criterion of 6.5 mg/l as absolute minimum does carry a potential for slight risk to coldwater species according to the EPA (1986b) criteria document. Oregon’s final issue paper also recognizes that for other life stages of cold water fish and aquatic life, reduction of DO concentration below saturation carries some risk of sublethal effect. Swimming speed in juvenile salmon declines markedly below dissolved oxygen concentrations of 7-8 mg/l (Dahlberg et al. 1968, as cited in ODEQ 1995). Results of several growth experiments summarized for coho salmon (Warren et al. 1973, as cited in ODEQ 1995) show that growth rate appears closely related to DO concentrations below 6.0 to 6.5 mg/l. ODEQ’s issue paper further reports that concentrations from near 8 to 6.5 mg/l resulted in measurable reductions in swim speed and maximum attainable growth and laboratory studies which have shown that blood is not fully saturated with oxygen at levels near 6.5 mg/l and changes in oxygen transfer efficiency occur. Sublethal effects that occur below 8 mg/l may control survival and success of juvenile salmonids in nature through reduced size observed in juvenile salmonids at DO concentrations below saturation. Specific to Lahontan cutthroat trout, the recovery plan (USFWS 1995) provides general guidance for habitat paramaters, stating that optimal lacustrine habitat is characterized by dissolved oxygen content > 8 mg/l in the epilimnion. Based upon this information, we do not concur with EPA’s determination of not likely to adversely affect for bull trout or Lahontan cutthroat trout regarding the cool water criterion.

It is apparent that bull trout have select habitat requirements. Although they may be present throughout large river basins, spawning and rearing fish are often found only in a portion of available stream reaches, typically the smaller, least disrupted watersheds or their tributaries (second to fourth order streams) (Rieman and McIntyre 1993). In these upland streams, where there is turbulence, waters are generally expected to be well-mixed and dissolved oxygen concentrations are usually near saturation levels (Gordon et al.1992). According to EPA’s DO criteria document (1986b), high temperatures compound the adverse effects of low dissolved oxygen concentrations. In the document, a dissolved oxygen salmonid growth study was reviewed showing the greatest effects and highest thresholds occurred at high temperatures (17.8 to 21.7°C) and DO levels down to 5 mg/l probably had little effect on growth rate at temperatures below 10°C. The criteria document (EPA 1986b) also reports the results of an acute study in which lethal DO concentrations increased at higher water temperatures and longer exposures. Low dissolved oxygen concentrations are often associated with higher temperatures because the gas solubility generally decreases as the temperature rises (Gordon et al. 1992). Because the bull trout temperature standard is very cold and their habitat is associated with DO concentrations reaching saturation, we believe it unlikely that DO will drop to the lower levels of the cool water criteria for extended periods of time.

The adverse effects of the proposed cool water criterion for bull trout, tempered by the factors discussed above, will affect all of the bull trout subpopulations with the Klamath River DPS and 21% (30/141=21.3%) of the bull trout subpopulations within the Columbia River DPS.

ODEQ has indicated in their policy memo to EPA (Attachment 1) that during the next triennial review, they will specify spawning time periods and areas to which the DO spawning criteria will apply. State Conservation Measures (Attachment 3) reiterate this commitment from ODEQ to working with the Services, Oregon Department of Fish and Wildlife (ODFW), and others with relevant life history information to identify geographic area and time periods when the spawning and cool water DO criteria apply (measure #4). State Conservation Measures also state that ODEQ will use 8 mg/l as the action level in the intergravel DO standard as a listing criterion for impaired waterbodies where there are relevant listed species, beginning with the year 2000 303(d) listing process (measure #6). Because of these actions, any adverse effects experienced by bull trout or LCT populations would be relatively short term. During the interim, these species will be protected through the induction of other State Conservation Measures; measure 2 describes a process whereby ODEQ and the Service will work together to address concerns with NPDES permits discharging into waters not water quality limited which support listed species, and which may affect the DO levels, and measure 3 specifies that ODEQ will develop a plan for implementation of the anti-degradation policy by the close of the year 2000.


Oregon Chub
Cool water DO criteria apply to the habitat of the Oregon chub in the Willamette valley, which require absolute minimum concentrations of 6.5 mg/l. In EPA’s biological assessment, the Umpqua River was also included within the current range of Oregon chub, however they do not occur outside the Willamette Basin. The Umpqua chub was recognized as distinct from the Oregon chub in 1991 (Markle et al.).

Oregon chub are found in slack water off-channel habitats such as beaver ponds, oxbows, side channels, backwater sloughs, low gradient tributaries and flooded marshes. These habitats usually have little or no water flow, silty and organic substrate, and considerable aquatic vegetation as cover for hiding and spawning (USFWS 1998b). Although specific dissolved oxygen requirements for the Oregon chub are unknown, Scheerer and Apke (1997) report that Oregon chub have been observed at sites with DO concentrations ranging from 3.0 mg/l to 9.9 mg/l. Oregon chub habitats, characterized by slack water with low or zero velocity, are typical of habitats which experience low dissolved oxygen concentrations (Gordon et al. 1992).

EPA has determined that the cool water dissolved oxygen concentration is not likely to adversely affect Oregon chub. Based upon the information presented above and the fact that the standard is set as an absolute minimum and seasonal and diurnal fluctuations will frequently increase DO levels above this minimum concentration, we concur with this determination.


Borax Lake chub
Warm water DO criterion (5.5 mg/l absolute minimum) applies to habitats supporting the Borax Lake chub.

The Borax Lake chub is endemic to Borax Lake and adjacent wetlands in the Malheur Lake basin. In a survey of conditions from 1991 to 1993, DO measurements ranged from 4.98 to 8.66 mg/l (Scoppetone et al. 1995). Because these fish currently reside in habitats with DO concentrations naturally less than those required under Oregon rules, EPA determined the warm water DO criteria is not likely to adversely affect the Borax Lake chub or its critical habitat.

We concur with EPA’s determination. The EPA dissolved oxygen criteria document (1986b) reports no significant effects to warm water fish at DO concentrations above the minimum criteria and field studies which show a concentration of 5 mg/l seems to represent a general dividing line between good and poor conditions for fish. The standard is set as an absolute minimum; diurnal and seasonal fluctuations will occur increasing DO above these minimum levels so these concentrations should not be experienced for extended periods of time.


Hutton Spring tui chub
Hutton Spring tui chub inhabits Hutton Spring and possibly another nearby spring in Alkali Subbasin of the Goose and Summer Lakes Basin where warm water DO criterion apply.

EPA inferred information about Hutton tui chub DO requirements from research on the tui chub from the Upper Klamath basin in which the mean minimum DO concentration was reported to be 0.59 + 0.04 mg/l. EPA considers these DO values as guidance given that the most sensitive life stage may not have been tested and the relative sensitivity of tui chub stocks from these geographically separate areas is unknown.

Warm water dissolved oxygen criteria apply to this basin, requiring DO concentrations not less than 5.5 mg/l as absolute minimum. Based on the information provided above, EPA determined that this criterion is not likely to adversely affect the Hutton tui chub. Although specific information is lacking for the Hutton Spring tui chub, we concur with this determination for the following reasons: 1) the standard is an absolute minimum, 2) other tui chub can likely tolerate concentrations significantly lower than the criteria, and 3) the EPA dissolved oxygen criteria document (1986b) reports no significant effects to warm water fish at DO concentrations above the minimum criteria and field studies which generally show that a concentration of 5 mg/l seems to represent a general dividing line between good and poor conditions for fish.


Lost River sucker and Shortnose sucker
Both the Lost River and the shortnose suckers reside in the upper Klamath basin where Oregon’s cool water dissolved oxygen criteria apply (6.5 mg/l absolute minimum). Studies by Monda and Saiki (1993), the U.S. Bureau of Reclamation (1997) and Scoppettone (1986) indicate that the lethal DO concentration for Lost River and Shortnose suckers are approximately 2.0-2.4 mg/l for larval and juvenile life stages and 2.8 mg/l for adults. The endpoint of these studies was lethality, which means that sublethal effects could occur at concentrations above those presented. In addition, values reported are from single variable tests without measurement of synergistic effects.
Adults and juvenile suckers of both species have been found in water where the DO ranges from 4 to 13 mg/l (Simon, University of California, EPA pers. comm., 1998), with the largest frequency of suckers observed in waters with concentrations of DO at approximately 9 mg/l. Buettner and Scoppettone (1990) also found juvenile suckers from the Upper Klamath Lake (Lost River, shortnose, Klamath largescale) at DO concentrations from 4.5 to 12.9 mg/l. Although suckers were found to occur in these habitats, this does not necessarily equate to their preferred habitat. These suckers are forced to live in habitat where water quality has been severely degraded and in which there are likely impacts occurring. Major fish kills occurred in Upper Klamath Lake from 1995 to 1997, affecting suckers and other species. It is believed that the loss of some age classes of suckers was significant.

In both larval and adult stages, these suckers have been found in waters where the DO concentrations were less than those in the Oregon water quality standards. Laboratory studies demonstrate that lethal dissolved oxygen concentrations for larval and juvenile life stages of these species are significantly less than those under the revised water quality standards. Therefore, EPA has determined that the Oregon cool water DO criteria are not likely to adversely affect the shortnose or Lost River suckers.

EPA’s DO criteria document (1986b) does not report any significant effects to warm water fish at DO concentrations above the minimum criterion. Specific to suckers, they report the results of an acute study with embryonic and larval stages of white suckers with close to 100% survival at DO concentrations <3 mg/l. They also report field studies showing that a concentration of 5 mg/l seems to represent a general dividing line between good and poor conditions for fish. Where these suckers co-occur with nonlisted salmonids (redband and rainbow trout) in the Klamath Basin, we expect that the salmonid spawning criteria would apply from March 1 - June 30. Minimum DO concentrations would be expected during the summer months (particularly July and August), when temperatures are at their peaks which is outside the LCT spawning period of February-early March. Since the DO criterion is an absolute minimum, DO concentrations will move above this with diurnal and seasonal fluctuations, so fish will not usually be exposed to lowest levels for extended periods of time. Therefore, we concur with EPA’s determination of not likely to adversely affect for the Lost River and shortnose sucker.


Warner sucker
Oregon warm water criterion apply to the habitat of the Warner sucker, requiring an absolute minimum concentration of 5.5 mg/l. Larval suckers are found in shallow backwater pools or on stream margins where there is no current, often among or near macrophytes, and venture near higher flows during the daytime to feed. Young of the year are often found over deep, still water from midwater to the surface but also move into faster flowing areas near the heads of pools. Juvenile suckers are usually found at the bottom of deep pools or in other habitats that are relatively cool and permanent, and prefer areas of streams protected from the main flow. Adults use stretches of stream with long pools having a greater than 5 ft. depth and a surface to bottom temperature differential of at least 2°C at low flows. Lake resident adults are generally found in the deepest available water where food is plentiful (USFWS 1998).

Although the general distribution of the Warner sucker is known, there is limited information available on stream habitat requirements, including dissolved oxygen. EPA has determined that the Oregon warm water dissolved oxygen criteria are not likely to adversely affect the Warner sucker as the lethal dissolved oxygen concentrations (2.0-2.8 mg/l) of the Lost River and shortnose suckers are almost 2 times lower than the absolute minimum required under the Oregon rules. EPA acknowledges that applying these values across species must be viewed with caution; however, the Warner sucker resides in a habitat (warm, slow moving stream margins and pools) that is naturally subjected to lower DO concentrations than that of the Lost River and shortnose suckers.

EPA’s DO criteria document (1986b) does not report any significant effects to warm water fish at DO concentrations above the minimum criteria. Specific to suckers, EPA reports the results of an acute study with embryonic and larval stages of white suckers with close to 100% survival at DO concentrations <3 mg/l. They also report field studies showing a concentration of 5 mg/l as a general dividing line between good and poor conditions for fish. Larval suckers are found almost anywhere in calmer sections of the streams such as shallow backwater pools or in stream margins, but never far from larger pools. Although the low-velocity, slack water habitat areas would typically experience low dissolved oxygen concentrations (Gordon et al. 1992), access to the larger pools with greater flow and predictably greater oxygen levels, would thereby limit possible exposure to the absolute minimum DO concentration. Since the DO criterion is an absolute minimum, diurnal and seasonal fluctuations will usually increase DO levels above this so fish will not be exposed for extended periods. In addition, there are streams where the Warner sucker co-occurs with nonlisted salmonids and those areas would be covered by the salmonid spawning criteria and cold water aquatic life criteria. Therefore, we concur with EPA’s determination that the warm water dissolved oxygen concentrations are not likely to adversely affect the Warner sucker.


Foskett speckled dace
Oregon’s warm water DO criterion (absolute minimum 5.5 mg/l) applies to Foskett Spring in the Coleman subbasin of the Warner Valley, where the Foskett speckled dace is found. Foskett Spring is a cool water spring with temperatures recorded at a constant 18°C over a 2 year period. The spring is a pool that is approximately 5 meters across and a shallow channel that flows toward Coleman Lake. Although there is no information on the DO requirements specific to Foskett speckled dace, there is information presented by Castleberry and Cech (1993) on the mean minimum DO requirements for other speckled dace which are 0.8 + 0.06 mg/l. EPA cautions that this information would be considered as guidance, as the most sensitive life stage may not have been tested and the relative sensitivity of the speckled dace stocks from various geographic areas is unknown. With this in mind, the Oregon DO criteria are greater than 4 times that of the minimum requirements for speckled dace in general and therefore, EPA has determined that the warm water DO criteria are not likely to adversely affect the Foskett speckled dace.

DO requirements for speckled dace appear to be relatively low. The DO criteria document (EPA 1986b) did not report any significant effects to warm water fish at concentrations above the 5.5 mg/l, while they do report field studies showing a concentration of 5 mg/l seems to represent a general dividing line between good and poor conditions for fish. Also, the criterion is set as an absolute minimum concentration. Therefore, we concur with EPA’s determination that the warm water dissolved oxygen concentrations are not likely to adversely affect Foskett speckled dace.


Vernal Pool fairy shrimp
These fairy shrimp reside in the Agate Desert, within the Rogue Basin where cold water dissolved oxygen criteria apply, requiring an absolute minimum of 8.0 mg/l DO. These shrimp are adapted to intense fluctuations within their environment from wet to completely dry. Although the DO requirements of this species are unknown, the BA states that all of the larger branchiopods can regulate oxygen consumption and live at low oxygen concentrations (Thorp and Covich 1991). Furthermore, Horne (1971) reported that a related species was able to tolerate dissolved oxygen concentrations as low as 1.3 mg/l. Because the fertilized eggs from this species can withstand desiccation and remain viable, there are no minimum DO requirements for this life stage. Given the nature of the harsh temporary habitats that these shrimp live in, EPA believes that the life history of these shrimp demonstrate that they are able to withstand extremely low concentrations of DO and has determined that the cold water DO criteria are not likely to adversely affect the Vernal Pool fairy shrimp. Based on the information presented, we concur with EPA’s determination.


Oregon spotted frog and Columbia spotted frog
These spotted frogs inhabit waterbodies that would be regulated by cold, cool and warm water DO criteria. Although there is no known information on the specific DO requirements for these species, Hayes (1998) noted some evidence that concentrations of DO < 5.0 mg/l could detrimentally affect spotted frogs by compromising the immune system. Since the lowest DO concentration that would be allowed under the revised rules is 5.5 mg/l, EPA has determined that the criteria are not likely to adversely affect the Oregon and Columbia spotted frogs. We don’t object to EPA’s determination.


Temperature Standard

Measurement
The temperature standard is measured as the 7-day moving average of the daily maximums. Buchanon and Gregory (1997) state that the 7-day average maximum is usually 0.5 to 2.0°C lower than the highest daily maximum temperature during the summer. The BA presents a hypothetical 7-day period for a stream meeting the criterion of 64°F (17.8°C), constructed to evaluate the potential time spent at or above sublethal thresholds under a criteria measurement framed as the 7-day moving average of the daily maximum. This example illustrated that the 7-day moving average can mask the magnitude of temperature fluctuation and the duration of exposure to daily maximum temperatures. In addition, the effects of cumulative exposure history, which could also affect aquatic organisms, are not taken into account within this measure.

The temperatures used in EPA’s hypothetical example varied diurnally 2°C or less for six of the seven days and 2.3°C on the seventh. This variability is rather small compared to the real stream data provided by ODEQ which shows diurnal fluctuations of 10°C are common during the summer months for streams with a 7-day statistic close to the 64°F standard (65.0 or 65.1°F). The ODEQ data are for streams least impacted within their respective basins. In streams where there is greater anthropogenic alteration, the magnitude of the fluctuation and duration is much greater, and thus, the potential exposure of aquatic organisms to these extremes is also greater.

Interpretation
Although temperature is expressed as a single parameter in the context of the water quality standards, thermal regimes are established through the complex interactions of a number of processes. Factors that influence the ambient water temperature include air temperature, channel morphology, riparian vegetation structure and function, groundwater, wetland complexes, and flow volume. Alteration of one or more of these parameters leads to thermal alteration through various mechanisms such as: increased solar radiation on the surface area of streams resulting from loss of riparian vegetation; increased stream surface area resulting from channelization of the stream channel; or decreased cold water inflow resulting from dewatering of groundwater sources. In addition, the number, distribution and accessability of cold-water refugia are important in modulating the impact of temperature on salmonids.

For their biological assessment, EPA conducted an in-house review related to salmonid temperature criteria (Berman, Appendix H of the BA) in addition to commissioning an extensive review by an outside source (Coutant, Appendix H of the BA). The review by Berman focused on the effects of sublethal temperatures within an ecological context. This review reports that adverse affects can occur with relatively small temperature increases and sublethal temperatures have proven to be the more ecologically relevant parameter in assessing species viability. Elevated temperatures have been shown to affect the following: smoltification; growth rate (which reflects significant reduction in fitness and alters migration timing); reproduction; resistance to disease and immunological response; and, competitive success.

Coutant (Appendix H of the BA) elaborates on the aspect of temperature standards. He states that there is abundant, generally robust, technical literature that defines suitable temperature ranges for various life stages. However, these findings are often laboratory-based and not interpreted in light of current understanding of the biological and ecological functions or natural water temperature fluctuations. Temperature effects in the environment are much more complex than represented by most numerical limits.

Much of the published literature reports results of laboratory studies which are limited in scope, reflecting only certain aspects of the species physiological requirements. Also, studies are conducted in a very limited context without the diversity and variability found in natural habitats. Consequently, comparing the laboratory results to expected results in a natural ecosystem is challenging, especially when using this information to develop a numeric water quality standard.

When the numeric standards are applied in combination with narrative and antidegradation standards, protection to the aquatic ecosystem may be much greater than any standard in isolation. The State has taken a progressive approach in setting a narrative temperature standard for the protection of federally listed threatened and endangered species, although thus far, the state has not had the opportunity to formulate guidance associated with the standard leaving it open to broad interpretation and difficult to implement.


Bull trout
Within the BA, EPA states that the 10°C criterion for spawning, rearing, and resident adult bull trout adequately protects the life history stages based upon information reported in the literature. They further state that, given that bull trout spawn in late summer through fall (late August -November) and have an egg incubation period lasting from fall until April, the criterion applied as a summer maximum should be protective of life history stages occurring at other times of the year when temperatures are cooler.

Although EPA believes that the numeric criterion is appropriate for spawning, rearing and resident forms, they do not believe the standard adequately protects migrating bull trout because Oregon has not designated migration corridors for protection. Bull trout populations have become largely fragmented and isolated in upper reaches of drainages due to elevated temperatures (Pratt 1992) and, as a result, have experienced decreased species fitness and viability. Without this migratory corridor designation, remaining bull trout populations may not be protected. Because migratory corridors are not included in the designation, EPA determined that the bull trout criterion is likely to adversely affect Columbia River Basin and Klamath Basin bull trout.

We concur with EPA’s determination that the temperature criterion is likely to adversely affect bull trout. However, our concurrence is not based solely on the lack of migratory corridor designation, but also related to egg incubation temperatures. McPhail and Murray (1979) report on egg survival associated with different temperatures. At 4°C there was 80-95% survival; at 6°C, there was 60-90% survival; and at temperatures ranging from 8 to 10°C there was only 0-20% survival. Weaver and White (1985) report 4-6°C is needed for egg development for Montana bull trout. A figure representing the temperature requirements for bull trout by life stage, prepared from both laboratory studies and field observations, is included in the ODEQ issue paper (1995) and shows that egg incubation requires temperatures ranging from 1-6°C. Gould (1987) raised bull trout embryos under water temperatures fluctuating from 4.5-8.0°C. The Creston National Fish Hatchery has been rearing bull trout for the past five years and incubates eggs at a temperature of approximately 5.8°C (Fredenberg 1995, 1998). During temperature trials with egg incubation, no decreased survival attributed to temperature relationships was observed within the range of 3.1-7.2°C. However, they have not explored any temperatures higher than this (Fredenberg, Creston National Fish Hatchery, pers. comm., October 26, 1998).

The onset of bull trout spawning can occur as early as July or August (Buchanan 1997, Pratt 1992) in certain basins when stream temperatures would be expected to reach their summer maxima and could reach the numeric temperature criterion of 10°C. If stream temperatures did reach the criterion maximum (7-day average of daily maximums), eggs would not be exposed to the 10°C for the entire period but would experience fluctuations surrounding that temperature. Depending upon the duration of exposure to elevated temperatures and cumulative effects, there may be adverse effects on eggs.

The numeric temperature standard applies to the maximum summer temperatures experienced. Maximum stream temperatures in Oregon are typically reached in July or August (ODEQ 1995). Most bull trout spawning takes place in September and October, although in the Deschutes Basin (Metolius River) spawning may occur in July and in the Grande Ronde (Imnaha River) and Klamath Basins spawning may occur in August (Table 4). Eggs laid by early spawners in these basins could be exposed to the standard temperature of 10°C. Because the majority of spawning occurs after the summer peak stream temperatures, we believe only a small portion of the bull trout eggs would be exposed to the maximum temperature of 10°C. Therefore, a relatively small portion of the population would be affected. The majority of spawning occurs with the onset of fall when water temperatures should be cooled down below the standard. In addition, early spawning observed in the three basins mentioned above may be induced by spring sources of extremely cold temperatures, such as is the case in the Metolius River system (Ratliff 1992). These springs may not reach the maximum stream temperatures of the bull trout temperature standard.

Salmonids not only respond to maximum temperatures, but also to maximum diel fluctuations. In anthropogenically altered systems, the magnitude of fluctuation and the duration of elevated temperatures is greater than in unaltered systems (ODEQ 1995; Berman in Appendix H of BA). Thus, the potential exposure of aquatic organisms to these extremes is also greater. Although bull trout may be present throughout large river basins, spawning and rearing fish are typically found in only a small portion of available stream reaches - the smaller, least disrupted watersheds or their tributaries (second to fourth order streams). Most often spawners are in association with cold water springs and upwellings (Rieman and McIntyre 1993). Therefore, in bull trout designated use areas which will meet the bull trout temperature standard, eggs would not be expected to experience the extreme temperature fluctuations or extended durations of elevated temperatures which occur in the lower, more disturbed reaches.

The current standard set by the state is a significant improvement from the previous standard in improving habitat conditions for the native bull trout. When streams which are currently not meeting the temperature standard start to be restored with the development and implementation of TMDLs, the system will be moving in the direction necessary to support bull trout. Once streams come into compliance, the current bull trout range will be extended, eventually allowing for movement and interaction among the current isolated population segments, and leading to increased health of the populations.

The overlap of bull trout spawning starts with peak stream temperatures is most likely to occur in three basins, the Grande Ronde, the Deschutes, and the Klamath. Metapopulation (network of local subpopulations with varying frequencies of breeding among them) concepts of conservation biology theory are applicable to the distribution and characteristics of bull trout (Reiman and McIntyre 1993). Local subpopulations may become extinct, but can be reestablished by individuals from other subpopulations. Metapopulations provide a mechanism for spreading risk because the simultaneous loss of all subpopulations is unlikely. The contribution of each metapopulation to the recovery of the species is considered equally important in that each population may be evolutionarily significant and persistence may depend on any or all populations of the species (Li et al. 1995, as cited in Buchanan et al. 1997). Persistence of many bull trout populations throughout their range is deemed necessary for the conservation of their genetic diversity (Leary et al. 1993 and Spruell and Allendorf 1997, as cited in Buchanan et al. 1997). Given the equal importance of all population segments, adverse impacts to any one segment could be significant to the recovery of the species. However, application of the revised bull trout temperature standard is expected to result in an expansion of suitable bull trout habitat and a resulting net increase in these metapopulations which will positively benefit the species in Oregon.

EPA and ODEQ worked with the Services to develop measures intended to address adverse effects related to the temperature standards on listed anadromous fish species (Attachment 3). Several of thes measures apply to bull trout. Measure 8 explains that EPA will lead, with ODEQ and the Services participation, an interagency technical and a policy workgroup to review temperature issues and develop EPA Region 10 temperature criteria over the next two years. The proposal for this effort is included as Attachment 4 of this BO. The goal of this effort is to review and develop a temperature standard that meets the biological requirements of listed aquatic species for survival and recovery. EPA will recommend this temperature criteria to Pacific Northwest states and tribes for adoption. The State of Oregon will consider adopting this criteria as a state water quality standard during the 1999-2002 triennial review. Also, measure 9 specifies that ODEQ, working with the Services, ODFW, and others with relevant life history information, will identify the geographic area and time period (including migration corridors) when the bull trout temperature criterion will apply to maintain the viability of native Oregon bull trout.

Several State Conservation Measures are intended to help prevent degradation of waters that meet the current standard, while the temperature standard is reviewed. Measure 2 outlines a process whereby ODEQ and the Service will work together to address concerns with NPDES permits discharging to waters not limited for temperature which support listed species and may affect the temperature. In addition, measures 1 and 3 state that ODEQ will develop a plan for implementation of the antidegradation policy and guidance for implementation of the narrative temperature criteria for threatened and endangered species and cold water refugia by the end of the year 2000 with involvement from the Services and EPA. Finally, contingent upon funding from the Services and EPA, ODEQ will expand water temperature monitoring into the spring and fall.


Lahontan cutthroat trout
Lahontan cutthroat trout (LCT) inhabit isolated desert streams in southeast Oregon where salmonid spawning and rearing criteria apply. Spawning criteria [55°F (12.8°C)] apply from March 1 through June 30 and rearing criteria [64°F (17.8°C)] apply from July 1 through February 30.

EPA determined that the spawning criterion is not likely to adversely affect LCT based upon the results of constant temperature studies indicating a spawning tolerance range of 41-61°F (5-16°C) and a preferred spawning temperature of 55°F for LCT (Coffin, USFWS, EPA pers. comm., 1998).

EPA also concluded that the rearing temperature is not likely to adversely affect LCT based upon a chronic stress study of young-of-the year LCT (lake stock) (Dickerson and Vinyard 1999). The study found that fish acclimated to 13°C suffered no significant mortality at temperatures of 24°C and below, and there was no difference in growth of fish held at 22°C relative to fish held at cooler temperatures. Fish exposed to fluctuating temperatures from 20-26°C did not grow as much as fish maintained at a constant temperature of 13°C or 20°C. From this study, the upper thermal limit for growth and survival in LCT was determined to be between 22°C and 23°C, when food availability is high.

The Lahontan Cutthroat Trout Recovery Plan (USFWS 1995) identifies general guidance for various habitat parameters for fluvial and lacustrine cutthroat trout. For water temperature the optimal fluvial cutthroat trout habitat is characterized by clear cold water with an average maximum summer temperature of <22°C (72°F) and relatively stable summer temperature regime averaging about 13°C (55°C) + 4°C (7°F). The plan also notes that Humboldt River LCT can tolerate water temperatures as high as 27°C (80°F) for short periods of time and that lacustrine LCT exist in rather diverse habitat conditions ranging from small, relatively infertile alpine lakes to large, highly alkaline desert waters.

Information provided above indicates that application of the salmonid spawning and rearing criteria to waters inhabited by LCT should be protective. In addition, criteria do not exceed temperatures reported by Dunham (1999) to show adverse affects to LCT in his review of their known thermal biology. Therefore, we concur with EPA’s determinations that proposed temperature standards will not likely adversely affect LCT.


Oregon chub
The Oregon chub is endemic to the Willamette River drainage with current distribution limited to four sub-basins: Mainstem Willamette, Middle Fork Willamette, Coast Fork Willamette, and Santiam (USFWS 1998). Within the current Oregon chub habitats, salmonid spawning (55°F) and rearing (64°F) criteria apply. The BA also states that there are some populations in waters designated for protection under the 20°C criterion for the Willamette River; however, those are historic populations which we do not considered as part of the current distribution.

The USFWS Oregon Chub Recovery Plan (1998b) reports that Oregon chub spawning occurs from the end of April through September at temperatures exceeding 16°C (61°F). Scheerer and Apke (1997) report that during June, July, and August spawning was observed at temperatures ranging from 16.5°C (61.7°F) to 20.5°C (68.9°F). These researchers also determined maximum lethal water temperatures for Oregon chub through laboratory experiments to be approximately 31°C (87.8°F), with no change in behavior noted until temperatures reached 31°C.

From this information, which shows the upper thermal tolerance of adult Oregon chub is significantly higher than the maximum allowable water temperatures under the Oregon criteria, EPA determined that the salmonid spawning and rearing temperatures are not likely to adversely affect Oregon chub. We concur with this determination based upon the information presented and because Oregon chub off-channel habitats (beaver ponds, oxbows, side channels, backwater sloughs, low gradient tributaries and flooded marshes) would seemingly experience elevated temperatures during summer maxima, higher than those standards proposed for approval.


Hutton Spring tui chub, Borax Lake chub, Warner sucker, shortnose sucker, Lost River sucker, Foskett speckled dace, vernal pool fairy shrimp
These species occur in portions of Oregon designated by ODEQ as warm water habitat. Warm water criterion were withdrawn during the temperature standards revision process, as an inadvertent oversight due to the state’s urgent need to protect coldwater biota. The State intends to develop numeric criteria for these waterbodies (Attachment 3), but until such time it will utilize its narrative temperature standards and its antidegradation policy to provide protection. According to the ODEQ letter (Attachment 1), the following provisions are applicable under the narrative criteria.

No surface water temperature increase resulting from anthropogenic activities is allowed:

1. In stream segments containing federally listed threatened and endangered species if the increase would impair the biological integrity of the threatened and endangered population.

2. In Oregon waters when the dissolved oxygen levels are within 0.5 mg/l or 10% saturation of the water column or intergravel DO criterion for a given stream reach or subbasin.

3. In natural lakes.

Currently, there is no guidance for interpretting the narrative standard related to federally-listed threatened and endangered species. Without such guidance, the narrative standard could be open to a broad interpretation of the language, “ impair the biological integrity”. ODEQ has clarified that the intent of the language. A temperature increase will be considered a factor if it could directly impact listed species (Sturdevant, ODEQ, pers. comm., 1998). For example, as determined for the bald eagles, an increase in temperature is not likely to have a direct adverse effect on the species.

EPA has determined that with implementation of the three narrative temperature criteria, as well as the antidegradation policy, the temperature criteria revisions are not likely to adversely affect these species. However, we have concern with protection of these aquatic species based solely on the provisions in the narrative criteria and do not concur with EPA’s determination. Although the narrative standard for threatened and endangered species has great potential to provide protection, at this time there is no guidance related to interpretation and application. Consequently, the narrative criteria could be interpreted very broadly and may not be implemented to any significant degree.

EPA and ODEQ worked with the Services to develop measures intended to address adverse effects related to the temperature standards on listed aquatic species (Attachment 3). During the next triennial review, ODEQ has committed to developing numeric temperature criteria (possibly site specific) for warm and cool water species with the involvement of EPA and the Services. Prior to completion of this numeric criteria, other measures are intended to provide interim protection. Measure 2 outlines a process whereby ODEQ and the Service will work together to address concerns with NPDES permits discharging to waters not limited for temperature where listed species occur, but which may affect the temperature. Measures 1 and 3 state that ODEQ, with involvement from the Services and EPA, will develop a plan for implementation of the antidegradation policy and guidance for implementing narrative criteria for threatened and endangered species by the end of the year 2000.


pH Standard

ODEQ revised its standard to accommodate the full range of apparent natural variability in pH found in Oregon (ODEQ 1995). The state experienced many technical violations of the criterion during the 1980-1990 period, leading to an assessment of the differences between natural and anthropogenic effects.

The analysis of the pH standard presented in Oregon’s Water Quality Standards Review document (1995) notes that the pH standard exceedances are primarily due to natural variation in the state’s aquatic systems. Eastern Oregon basins, with forestry and range land grazing as the primary human activities, have the highest percent violations of the upper-end of the old pH standard range. Frequent pH criteria exceedances occur in basins which have minimal nutrient enrichment and consistent violations occur in the upper portions of these watersheds in areas of minimal human impacts. In coastal streams low end pH violations occur primarily during winter high rainfall events. Field data show these streams are poorly buffered and groundwater contributions to flow are minimal. No recognized human activities occur in these watersheds that would easily account for low pH in streams. For the poorly buffered Cascade lakes, pH varies naturally from about 5.5 to 9.5. Alpine lakes are expected to have low pHs due to low alkalinity and data from the Western Lakes Survey confirmed that 98% of the randomly samples lakes had pHs below neutrality under natural conditions.

According to the EPA (1986a) criteria document, the European Inland Fisheries Advisory Commission concluded that the pH range which is not directly lethal to fish is 5 to 9. However, the upper limit of 9 was based upon only one reference. Although this range is not directly lethal to fish, pH changes within this range could affect the toxicity of several pollutants. The commission further concluded that from the pH range of 6.0 to 6.5, the effect on fish was unlikely to be harmful to fish unless free carbon dioxide is present in excess of 100 ppm. Based upon this information, EPA recommended pH criteria for freshwater aquatic life is 6.5 to 9.0 and for marine aquatic life is 6.5 to 8.5 with a maximum change of 0.2 pH units.

Within the triennial review issue paper (1995), ODEQ reports that an enormous amount of new data related to pH and acid rain has been developed over the past 10 years. Results contained in reports from the National Acid Precipitation Assessment Program (body responsible for coordinating research) were summarized for general biological effects anticipated with acidification of surface waters. In the pH range of 6.0 to 6.5, anticipated effects to the aquatic system would result in a small decrease in species richness of phytoplankton, zooplankton, and benthic invertebrate communities from the loss of a few highly acid-sensitive species, but no measurable change in community abundance or production. Some adverse effects, such as decreased reproductive success, may occur for highly acid-sensitive fish species (e.g. fathead minnow, striped bass). The critical pH value for rainbow trout is reported to be about 5.5, and the white sucker is about 5.2. For amphibians, the ODEQ issue paper (1995) reports that the range of toxic pH to common amphibian species extends from 3.5 - 6.0.

EPA concurs that waterbodies in many areas of Oregon have naturally varying pHs outside the range of 6.5 to 8.5 based upon the information presented in ODEQs issue paper. They also concluded that biota in these waterbodies have adapted to such conditions and that, although pH itself may have deleterious effects on aquatic biota, other chemical and physical factors generally have a more pronounced affect on the biota.


Bull trout and Lahontan cutthroat trout
Revisions to the pH criterion for a decrease from 6.5 to 6.0 apply only to Cascade lakes either above 3,000 feet elevation in the Umpqua, Rogue, Willamette, Sandy, Hood, and Deschutes Basins, or 5,000 feet elevation in the Klamath Basin. The revised high end of the pH criterion of 9.0 applies to the John Day, Umatilla, Grande Ronde, Walla Walla, and Powder basins where bull trout could be exposed. Lahontan cutthroat trout populations do not exist in any of the basins where pH criteria revisions apply, and therefore, are not considered here.

Although some population segments of bull trout could theoretically be exposed to lakes protected by the 6.0 pH criterion, EPA concludes that biotic systems developed within naturally acidic alpine lakes would preclude the presence of low pH sensitive trout. Other than Odell Lake, bull trout are unknown from Cascade alpine lakes. Therefore, only the Odell Lake population would potentially be exposed to pH criteria less than 6.5. Odell Lake receives very minimal impact from human sources. Any lower pH would be expected to be a natural occurrence and those bull trout living in the lake would be expected to be adapted to the natural conditions.

EPA’s BA states that within the ODEQ (1995) issue paper, both trout and salmon species are reported to be sensitive to a pH range of 9.2 to 9.7, depending on the life stage. EPA further reports that levels of pH greater than 9.0 may adversely affect benthic invertebrate populations, thereby altering the food base for salmonids.

ODEQ has included an action limit applying to all basins with an upper pH criterion of 9.0, triggering a follow-up study if the pH from enough samples taken during the growing season is greater than 8.7. Furthermore, the criteria for listing these waters on Oregon’s 303(d) list is a pH of 8.7. This will help to assure that waters at this level will receive attention to determine if additional management measures are needed to lower the pH.

Based upon this information, EPA determined that the revised pH standards are not likely to adversely affect bull trout or LCT. We concur with the determination.


Oregon chub, Hutton Spring tui chub, Borax Lake chub, Warner sucker, and Foskett speckled dace
EPA determined that these species are not likely to be adversely affected by the revisions to the pH criterion because they are not in basins or waterbodies where the revisions to the pH criteria apply, with the possible exception of the provision for waters impounded by dams. Since this exception will be handled as a water quality standards revision on a case-by case basis, the EPA decision in each of these cases will involve a separate ESA consultation. Since these revisions do not apply to the aforementioned species and the exception would involve a separate section 7 consultation, these species do not require consultation on the revision to the pH criteria at this time.


Lost River and Shortnose sucker
Criterion revisions in the Klamath basin, where these two sucker species reside, include the lowering of the pH range for Cascade lakes over 5,000 feet to a pH of 6.0 and the lowering of the pH range for the remainder of the freshwaters in the basin from a pH of 7.0 to 6.5. Since the suckers are not found in Cascade Lakes over 5,000 feet, the applicable criterion in their habitat is pH 6.5 to 9.0. The upper end of the pH range did not change with this triennial review, therefore it will not be considered for this consultation.

EPA determined that the Oregon water quality criterion for pH is not likely to adversely affect the Lost River and shortnose suckers. The revisions to the pH criterion for these species is within the range cited by EPA (1986) to adequately protect freshwater fish and bottom dwelling invertebrates. Furthermore, more recent information gathered by ODEQ (1995) for their issue paper indicates that a low end pH of 6.5 should not deleteriously affect these species.

In considering the information presented, we concur with EPA’s determination of not likely to adversely affect.


Vernal Pool fairy shrimp
None of the pH criteria revisions apply to the habitat of the Vernal Pool fairy shrimp. Therefore, EPA made a not likely to adversely affect determination. Because no revisions apply, this species does not require consultation on the revised pH standard at this time.


Spotted Frogs
EPA did not make a determination for these candidate species due to insufficient data for a thorough analysis.


Summary of Affect Calls
Table 5 summarizes the affect calls presented in this biological opinion.


Table 5. Summary of affect calls to species considered in this BO. NL - not likely to adversely affect; L - likely to adversely affect; NO - no objection to EPA’s determination; NC - not considered in this consultation.

Species	DO	Temperature	pH
Bull trout	L	L	NL
Lahontan cutthroat trout	L	NL	NL
Oregon chub	NL	NL	NC
Borax Lake chub	NL	L	NC
Hutton Spring tui chub	NL	L	NC
Warner sucker	NL	L	NC
Lost River sucker	NL	L	NL
Shortnose sucker	NL	L	NL
Foskett speckled dace	NL	L	NC
Vernal pool fairy shrimp	NL	L	NC
Oregon spotted frog*	NO	NC	NC
Columbia spotted frog*	NO	NC	NC

Cumulative Effects
Cumulative effects are those effects of future State, local, or private actions that are reasonably certain to occur within the action area considered in this biological opinion. Future Federal actions that are unrelated to the proposed action are not considered in this section because they require separate consultation pursuant to section 7 of the Act.

Due to the mixed positive and negative impacts of such a variety of actions across the state, the FWS is unable to identify any cumulative effects that are likely to be both reliably predictable and of significant impact to any given listed species. Though we acknowledge that cumulative effects will occur, we cannot predict what these effects will be. Therefore, for the purposes of this consultation, FWS assumes that impacts from non-Federal activities which have affected habitat of listed aquatic species will continue in the short term at similar intensities as in recent years.


CONCLUSION
After reviewing the current status of the potentially affected species identified in Table 1, the environmental baseline for the action area, the effects of EPA’s approval of the revised standards for dissolved oxygen, temperature, and pH, and the cumulative effects, it is the FWS's biological opinion that the proposed approval of the revised Oregon Water Quality Standards is not likely to jeopardize the continued existence of the Klamath or Columbia DPSs of bull trout, Lahontan cutthroat trout, Oregon chub, Hutton Spring tui chub, Foskett speckled dace, Warner sucker, Borax Lake chub, Lost River sucker, shortnose sucker, or vernal pool fairy shrimp and is not likely to destroy or adversely modify the designated critical habitat of the Borax Lake chub or Warner sucker or the proposed critical habitat of the Lost River and shortnose sucker. No critical habitat has been designated for bull trout, Lahontan cutthroat trout, Oregon chub, Hutton Spring tui chub, Foskett speckled dace or Vernal Pool fairy shrimp, therefore, none will be affected. A summary of the FWS’s rationale in reaching this conclusion is as follows:


Bull Trout (Klamath and Columbia DPSs)
•ODEQ has committed to applying an IGDO level that is above the threshold for adversely affecting growth and survival.
•The adverse impact of EPA’s proposed approval of the cool water criterion will be minimized by the bull trout temperature standard and the fact that their habitat is associated with DO concentrations reaching saturation, such that it is unlikely that DO will drop to the lower levels of the cool water criteria for extended periods of time.
•Any adverse effects of the cool water DO criterion will be short-term (through 2002-2003), as ODEQ will identify geographic area and time period when the DO criteria apply during the next triennial review.
•ODEQ and the FWS will coordinate on the NPDES permit program to minimize the effects of permits proposed in areas designated for bull trout beneficial use.
•The adverse impacts of the temperature criterion will be minimized because higher summer temperatures will only overlap with populations in three watersheds (Metolius, Imnaha, and Klamath), containing subpopulations.
•Adverse impacts of potential summer maximum temperatures overlapping with early spawning will be further minimized due to location of spawning and rearing areas in higher stream reaches or springs where the coldest water temperatures are likely to occur.
•Certain Oregon waterbodies have natural variation in pH unrelated to to human disturbance; bull trout and other organisms have evolved under these conditions.
•Low-end pH values are confined to Odell Lake, containing only one subpopulation of the Columbia River DPS (1/141=0.7% of DPS). High end values will not directly affect bull trout.
•Waterbodies with pH approaching the upper limit of 9.0 (8.7) will be studied to determine if pH levels are natural or resulting from anthropogenic influences and included under the Oregon 303(d) listing. This will result in the application of beneficial management measures.

Lahontan cutthroat trout
•Proposed coolwater DO criteria will have greatest effect on young of late spawning individuals.
•Any adverse effects of the cool water criterion will be short-term (through 2002-2003), as ODEQ will identify geographic area and time period when the DO criteria apply during the next triennial review.
•ODEQ and the Service will coordinate on the NPDES permit program to minimize the effects of permits that are proposed in areas with LCT.
•Only a small amount of LCT range extends into Oregon.
•Studies conducted with LCT indicate an upper thermal limit for growth and survival between 22 - 23°C, which is well above relevant criteria.
•pH criteria revisions are not applicable in waterbodies inhabited by LCT.

Oregon chub
•Oregon chub is found in habitats typical of low DO concentrations.
•The upper thermal tolerance of adult Oregon chub is significantly higher than the maximum allowable under the revised criterion.
•Spawning occurs at temperatures approaching the salmonid rearing temperature criterion.
•pH criteria revisions are not applicable in waterbodies inhabited by Oregon chub.

Borax Lake chub
•Dissolved oxygen measures collected in Borax Lake chub habitat bracket the absolute minimum warm water criterion.
•In the dissolved oxygen criteria document, EPA reports no significant effects to warm water fish at DO concentrations above the criteria.
•Any adverse effects related to temperature will be short term, as ODEQ has committed to develop numeric criteria for listed species included in the designation of warm water habitat during the next triennial review.
•ODEQ and the FWS will coordinate on the NPDES permit program to minimize the effects of issuing permits in waters of listed aquatic species.
• The pH criteria revisions are not applicable in waterbodies inhabited by the Borax Lake chub.
Hutton Spring tui chub
•Warm water DO criteria concentrations are significantly higher than those tolerated by tui chub.
•In the DO criteria document, EPA reports no significant effects to warm water fish at DO concentrations above the criterion.
•Any adverse effects from temperature will be short term, as ODEQ has committed to develop site specific criteria for listed species included in the designation of warm water habitat during the next triennial review.
•ODEQ and the FWS will coordinate on the NPDES permit program to minimize the effects of issuing permits in waters of listed aquatic species.
•pH criteria revisions are not applicable in Hutton Spring tui chub waters.
Lost River and Shortnose suckers
•Lethal DO concentrations for these species are less than half of the absolute minimum concentration allowed under cool water criteria.
•In the DO criteria document, EPA reports no significant effects to warm water fish at DO concentrations above the criteria.
•These suckers usually co-occur with non-listed salmonids where higher concentrations of DO apply.
•Lowering the pH criteria from 7.0 to 6.5 still remains within the range EPA found to adequately protect freshwater fish and bottom dwelling invertebrates.
Warner sucker
•Lethal DO concentrations to other endangered sucker species (Lost River and shortnose) are almost two times lower than the absolute minimum required under the criteria revisions.
•The DO criterion is measured as an absolute minimum, diurnal and seasonal fluctuations will increase DO concentrations above this level.
•In the DO criteria document, EPA reports no significant effects to warm water fish at DO concentrations above the criteria.
•Any adverse effects related to temperature will be short term, as ODEQ has committed to develop numeric temperature criteria for listed species included in the designation of warm water habitat during the next triennial review.
•ODEQ and the FWS will coordinate on the NPDES permit program to minimize the effects of issuing permits in waters of listed aquatic species.
• The pH criteria revisions are not applicable in waterbodies inhabited by Warner sucker.
Foskett speckled dace
•Mean minimum DO requirements for speckled dace may be four times lower than the Oregon DO criteria.
•In the DO criteria document, EPA reports no significant effects to warm water fish at DO concentrations above the criteria.
•ODEQ has committed to develop numeric temperature criteria for listed species included in the designation of warm water habitat during the next triennial review; any impacts related to temperature will be short term.
•ODEQ and the FWS will coordinate on the NPDES permit program to minimize the effects of issuing permits in waters of listed aquatic species.
• The pH criteria revisions are not applicable in waterbodies inhabited by the Foskett speckled dace.
Vernal pool fairy shrimp
•These shrimp are adapted to wide fluctuations within their environment from wet to completely dry.
•Other branchiopods can regulate oxygen consumption and live at low oxygen concentrations.
•ODEQ has committed to develop numeric temperature criteria for listed species included in the designation of warm water habitat during the next triennial review; any impacts related to temperature will short term.
•ODEQ and the Service will coordinate on the NPDES permit program to minimize the effects of permits in waters of listed aquatic species.
•The pH criteria revisions are not applicable to vernal pools inhabited by this species.



Sections 4(d) and 9 of the Act, as amended, prohibit taking (harass, harm, pursue, hunt, shoot, wound, kill, trap, capture or collect, or attempt to engage in any such conduct) of listed species of fish or wildlife without a special exemption. Harm is further defined to include significant habitat modification or degradation that results in death or injury to listed species by significantly impairing behavioral patterns such as breeding, feeding, or sheltering. Harass is defined as actions that create the likelihood of injury to listed species to such an extent as to significantly disrupt normal behavior patterns which include, but are not limited to, breeding, feeding, or sheltering. Under the terms of section 7(b)(4) and section 7(a)(2), taking that is incidental to and not intended as part of the agency action is not considered a prohibited taking provided that such taking is in compliance with the terms and conditions of this incidental take statement.
The measures described below are non-discretionary, and must be implemented by the agency so that they become binding conditions of any grant or permit issued to the applicant, as appropriate, in order for the exemption in section 7(a)(2) to apply. The Environmental Protection Agency has a continuing duty to regulate the activity covered by this incidental take statement. If EPA (1) fails to require the applicant to adhere to the terms and conditions of the incidental take statement through enforceable terms that are added to the permit or grant documents, and/or (2) fails to retain over sight to ensure compliance with these terms and conditions, the protective coverage of section 7(o)(2) may lapse.


EFFECT OF THE TAKE

Amount or Extent of Take

General Statement:
For the purposes of this BO, incidental take is defined as take that results from EPA’s approval of the Oregon revised water quality standards. Incidental take associated with waterbodies not meeting the standard is not associated with this EPA action, and consequently not covered under this incidental take statement.

The amount or extent of incidental take resulting from the proposed action of listed species is difficult to assess. Based on a review of information provided within the biological assessment, the FWS does not anticipate that the proposed approval of the revised Oregon water quality standards will at any time directly kill members of listed species considered in this Biological Opinion. However, the FWS recognizes and anticipates that take in the form of harm or harassment may occur for bull trout, Lahontan cutthroat trout, Borax Lake chub, Hutton Spring tui chub, Warner sucker, Lost River sucker, shortnose sucker, Foskett speckled dace, and vernal pool fairy shrimp. Harm is defined to include significant habitat modification or degradation that results in death or injury to listed species by significantly impairing essential behavioral patterns, including, breeding, feeding, or sheltering. Harass is defined as intentional or negligent act or omission which creates the likelihood of injury to wildlife by annoying it to such an extent as to significantly disrupt normal behavior patterns which include, but are not limited to, breeding, feeding, or sheltering.

The FWS anticipates incidental take of bull trout, Lahontan cutthroat trout, Borax Lake chub, Hutton Spring tui chub, Warner sucker, Lost River sucker, shortnose sucker, Foskett speckled dace, and vernal pool fairy shrimp will be difficult to detect, and finding dead or impaired specimens is unlikely. Losses may be masked by seasonal fluctuations in numbers or other causes. Furthermore, the FWS does not expect that it will be able to discover a precise number of chronically or sublethally affected individuals attributable to the proposed action, nor will it be able to define the extent of take (harm or harass) in terms of acres or stream miles affected. Therefore, incidental take in the form of harm and harassment will not be considered to be exceeded in those water bodies which are meeting the revised WQS, unless lethal effects are demonstrated.

Incidental take associated with this action will be of limited duration. FWS expects that development of the EPA and ODEQ conservation measures described in Attachments 2,3, and 4 will minimize take. ODEQ conservation measures resulting in rulemaking will require EPA approval and ESA section 7 consultation at which time incidental take will be reassessed for that action. Therefore, incidental take related to EPA’s approval of the DO and temperatures standards is authorized only until the EPA and ODEQ conservation measures are completed.

In the accompanying biological opinion, the Service determined that this level of anticipated take is not likely to result in jeopardy.


REASONABLE AND PRUDENT MEASURES

The Service believes the following reasonable and prudent measure is necessary and appropriate to minimize take:

1. EPA shall carry out the conservation measures described in Attachment 3 of this BO.

Terms and Conditions
To be exempt from the prohibitions of section 9 of the Act, EPA must comply with the following terms and conditions which implement the reasonable and prudent measure described above.

The following terms and conditions apply to implementing the reasonable and prudent measure number 1:

A. EPA, working with the ODEQ and NMFS, shall assist FWS in assessing consistency with conservation measures contained in Attachments 2,3, and 4 of this BO.

B. As soon as feasible following completion of the Regional Temperature Criteria Development Project (Attachment 4), EPA shall transmit the Regional Temperature Criteria to the ODEQ, and will recommend that ODEQ revise its temperature standard according to those criteria.


Terms and conditions of an incidental take statement usually include reporting and monitoring requirements that assure adequate action agency oversight of incidental take. In this case, given the large area and number of species addressed in this consultation and the difficulty of detecting incidental take from water quality effects in waters meeting water quality standards, monitoring of incidental take would mean a tremendous expenditure of resources. Also, incidental take is only authorized for a limited amount of time by the end of which results of any monitoring would likely not yet be available. Therefore, no term and condition addressing monitoring of incidental take is included. However, the FWS does request in its conservation measures that EPA cooperate with ODEQ so FWS obtains the results of any fish kill investigations occurring within waters meeting ODEQ water quality standards for DO, temperature, and pH.

The reasonable and prudent measures, with its implementing terms and conditions, are designed to
minimize the impacts of the incidental take that might otherwise result from the proposed action. With implementation of this measure, the FWS believes that incidental take of listed species will be minimized. If, during the course of the action, this level of incidental take is exceeded, such incidental take would represent new information requiring review of the reasonable and prudent measure provided. The EPA must immediately reinitiate consultation and provide an explanation of the causes of the taking and review with the FWS the need for possible modification of the reasonable and prudent measures.


Conservation Recommendations

Section 7(a)(1) of the Act directs Federal agencies to utilize their authorities to further the purposes of the Act by carrying out conservation programs for the benefit of endangered and threatened species. The term "conservation recommendations" is defined as suggestions from the Service regarding discretionary agency activities to: 1) minimize or avoid adverse effects of a proposed action on listed species or critical habitat; 2) conduct studies and develop information; and 3) promote the recovery of listed species. The recommendations provided here relate only to the proposed action and do not necessarily represent complete fulfillment of the agency's 7(a)(1) responsibilities.

1. EPA will assist ODEQ in development of TMDLs for water quality limited waterbodies. This could be in the form of additional funding to the State, allowing them to dedicate more personnel resources to the effort or direct technical assistance from EPA staff.

2. EPA will coordinate, conduct, and/or support research to determine specific limits of the conventional water quality parameters that adversely affect Columbia and Oregon spotted frogs and other stream dependent amphibians.

3. EPA will cooperate with ODEQ so FWS obtains the results of any fish kill investigations occurring within waters meeting ODEQ water quality standards for DO, temperature, and pH.

To be kept informed of actions that either minimize or avoid adverse effects or that benefit listed species or their habitats, the FWS requests notification of the implementation of any conservation recommendations.

This concludes formal consultation on the actions outlined in the request. As required by 50 CFR Part 402.16, reinitiation of formal consultation is required if: (1) the amount or extent of incidental take is exceeded; (2) new information reveals effects of the agency action that may affect listed species or critical habitat in a manner or to an extent not considered in this opinion; (3) the agency action is subsequently modified in a manner that causes an effect to the listed species or critical habitat that was not considered in this opinion; or (4) a new species is listed or critical habitat designated that may be affected by the action. In instances where the amount or extent of incidental take is exceeded, any operations that are causing such take must be stopped, and formal consultation must be reinitiated.

If you have questions regarding this biological opinion, please contact Elizabeth Materna or Stephen Zylstra at (503) 231-6179.


Sincerely




Russell D. Peterson
State Supervisor

cc:

Mike Llewelyn, Administrator, Water Quality Division, ODEQ, Portland, Oregon
Rick Applegate, Habitat Branch Chief, NMFS, Portland, Oregon
Assistant Regional Director, North Coast Ecoregion, USFWS, Portland, Oregon
Field Supervisor, Snake River Basin Field Office, Boise, Idaho
Field Supervisor, Western Washington State Office, Olympia, Washington





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Buchanan, D.V. and S.V. Gregory. 1997. Development of water temperature standards to protect and restore habitat for bull trout and other cold water species in Oregon. In Mackey, M.K. Brevir, and M. Monita (eds.), Friends of the Bull Trout Conference Proceedings.

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Dambacher, J.M., and K.K. Jones. 1997. Stream habitat of juvenile bull trout populations in Oregon, and benchmarks for habitat quality. Proceedings of the Friends of the Bull Trout Conference. Calgary, Alberta.

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Dunham, J. 1999. Stream temperature criteria for Oregon’s Lahontan cutthroat tourt Oncorhynchus clarki henshawi. Oregon Department of Environmental Quality.

Fraley, J.J. and B.B. Shepard. 1989. Life history, ecology and population status of migratory bull trout (Salvelinus confluentus) in the Flathead Lake River system, Montana. Northwest Science 63: 133-143.

Fredenberg, W. 1998. Experimental bull trout hatchery, progress report two experimental broodstock development 1995-1997. Creston National Fish Hatchery, Kalispell, MT. 17 pp.

Fredenberg, W. October 26, 1998. Creston National Fish Hatchery, Kalispell, Montana. Personal communication.

Fredenberg, W., P. Dwyer, and R. Barrows. 1995. Experimental bull trout hatchery progress report 1993-1994. Creston Fish and Wildlife Center, Kalispell, MT, and Bozeman Fish Technology Center, Bozeman, MT. 29 pp.

Goetz, F. 1991. Bull trout life history and habitat study. Thesis, Oregon State University, Corvallis, OR. 49 pp.

Gordon, N.D., T.A. McMahon, and B.L. Finlayson. 1992. Stream hydrology; an introduction for ecologists. John Wiley & Sons, West Sussex. 526 pp.

Gould, W.H. 1987. Features in the early development of bull trout (Salvelinus confluentus) Northwest Science, Vol.61, No. 4.

Hayes, M.P. June 4, 1998. Portland State University, Portland, Oregon. EPA personal communication.

Hayes, M.P. 1997. Final Report, Status of the Oregon Spotted Frog (Rana pretiosa sensustricto) in the Deschutes Basin and selected other systems in Oregon and Northeastern California with a rangewide synopsis on the species’ status. Prepared for the Nature Conservancy, under U.S. Fish and Wildlife Service Contract.

Hayes, M.P. 1994. The spotted frog in Western Oregon. Oregon Deptartment of Fish and Wildlife, Wildlife Diversity Program, Portland, OR.

Hollender, B.A. 1981. Embryo survival, substrate composition, and dissolved ocygen in redds of wild brook trout. M.S. Thesis, Univ. Of Wisconsin.

Horne, F.R. 1971. Some effects of temperature and oxygen concentration on Phyllopod ecology. Ecology 52: 343-347

Jones, K.K., J.M. Dambacher, B.G. Lovatt, A.G. Talabere, and W. Bowers. 1998. Status of Lahontan cutthroat trout in the Coyote Lake Basin, Southeast Oregon. No. Amer. J. of Fisheries Mgmt. 18:308-317.

Kann, J. 1998. Klamath Tribes, Chiloquin, Oregon. EPA personal communication.

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Li, H.W. and 12 coauthors. 1995. Safe havens: refuges and evolutionarily significant units. American Fisheries Society Symposium 17: 371-380.

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Key activities associated with the consultation are described in chronological order.


ODEQ initiated triennial review 5/22/92

Letters from ODEQ to National Marine Fisheries Service (NMFS) and FWS requesting involvement in triennial review10/19/92

Letter from ODEQ to Services requesting input on whether
extension of pH criteria to 9.0 would be protective of anadromous fish life stages 11/1/93

Public comment on draft WQS 7/28/95 - 9/19/95

Public hearings 9/5/95 - 9/12/95

Oregon adoption of WQS 1/11/96

Oregon submittal of revised WQS to EPA 7/11/96

EPA request for species list from the Services 1/15/97

Receipt of species lists:

FWS 3/19/97; updated 7/1/98
NMFS 2/10/97; updated 6/22/98

Consultation workshop with EPA, NMFS, FWS 2/21/97

Conference call to scope major issues (EPA and Services) 4/23/97

Conference call to reconnect (EPA and Services) 4/8/98

Directorate (FWS, EPA, NMFS, ODEQ) meeting to discuss consultation schedule 5/8/98

EPA letter to ODEQ confirming consultation schedule and invitation to participate 6/16/98

Meeting of EPA and Services to discuss biological assessment (BA) 7/16/98

Meeting of EPA, Services, and ODEQ to discuss mitigation options 9/9/98

Conference call among EPA, Services, and ODEQ to alternatives 10/5/98

Conference call among EPA, Services, and ODEQ to discuss alternatives 10/15/98

Meeting of EPA, Services, and ODEQ to discuss alternatives 10/22/98

Conference call among EPA, Services, and ODEQ to discuss alternatives 11/2/98

Conference call between the Services to discuss analysis of effects 11/4/98

Meeting of EPA, Services, and ODEQ to discuss alternatives 12/3/98

Informal meeting of EPA and Services 12/5/98

Meeting of EPA, Services, and ODEQ 12/9/98

Meeting of NMFS and FWS to discuss analysis of affects 12/16/98

Meeting of NMFS and FWS to discuss analysis of affects 12/30/98

Conference call among EPA, Services, ODEQ 1/11/99

Conference call among EPA, Services, ODEQ 1/14/99

Conference call among EPA, Services, ODEQ 1/28/99

Meeting with EPA, Services, ODEQ to discuss temperature review 2/10/99

Meeting with EPA, Services, ODEQ to discuss outcome alternatives 2/24/99

Conference call among EPA, Services, and ODEQ to discuss temperature review 4/29/99

Meeting of EPA, Services, and ODEQ to review comments on State draft
conservation measures 5/19/99

Meeting with EPA, Services, and ODEQ to review temperature review proposal 5/25/99

Conference call among EPA, FWS, and ODEQ regarding State’s draft
conservation measures 6/3/99

Conference call among EPA, Services, and ODEQ to discuss Service’s draft BOs 6/14/99

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