PUBLIC SUBMISSION | As of: February 09, 2009 Tracking No. 803bb8c6 Comments Due: March 10, 2008 |
Docket: FWS-R2-ES-2008-0031
Designating a 10(j) Experimental Population for the Reintroduction of Rio Grande Silvery Minnow into the Big Bend Area of Texas
Comment On: FWS-R2-ES-2008-0031-0002
Endangered and Threatened Wildlife and Plants; Establishment of a Nonessential Experimental Population of Rio Grande Silvery Minnow in the Big Bend Reach of the Rio Grande in Texas
Document: FWS-R2-ES-2008-0031-0003
Comment on FR Doc # E8-03385
Albuquerque, NM, 87105
??Attn: RGSM Proposed 10(j) Designation,??
Comment number 1. In the DEA, Recommended Research, item "3. Develop a
better understanding of water quality in the Rio Grande within and upstream of the
reestablishment area, including water entering from the Rio Conchos."
I think that its important that the "understanding of water quality" be directly linked
to the direct or indirect response of the silvery minnow and/or the quality of their
habitat (physical, chemical or biological characteristics - food, effect on
competition or predation, disease, parasite burden, etc.). For example, water
quality studies that emphasize or evaluate conditions for human health or their
recreation in the water may, or may not, provide the appropriate level of
understanding of the quality of water and how it will affect the survivability, growth
or reproduction of the Rio Grande silvery minnow.
I'd recommend that your item 3 be modified to state: "3. Develop a better
understanding of water quality in the Rio Grande as it affects the health of Rio
Grande silvery minnow or the quality of its essential fish habitat within and
upstream of the reestablishment area, including water entering from the Rio
Conchos."
Essential fish habitat could be defined as those "wasters and substrate necessary
for feeding, spawning, reproduction, cover, movement, or growth to maturity" and
include aquatic areas and their associated physical, chemical, radiological and
biological properties that are used by the Rio Grande silvery minnow."
It appears the DEA downplays the potential for the quality of water to affect, in
some regard, the survival of some fish or the recovery of the Rio Grande silvery
minnow in this reach. "This species 'may' also be affected by water quality
declines and interactions with non-native fish." Buhl (2002) demonstrated
empirically that whenever water quality is insufficient (e.g., the content of
dissolved oxygen in the water drops precipitously, or the concentration of
ammonia or copper is sufficiently elevated), then Rio Grande silvery minnow will
die, unequivocally. Rio Grande silvery minnow are not somehow immune or
resistant to a precipitous decline of water quality sufficient to suggest that
they "may" be affected; rather they shall be affected, especially when conditions
have declined to the extent that they are detrimental to aquatic life.
The statements in the proposed rule and the DEA should be more objective in this
reguard about this phenomena, ("Throughout much of its historic range, the
decline of the Rio Grande silvery minnow has been attributed to modification of the
flow regime (hydrological pattern of flows that vary seasonally in magnitude and
duration, depending on annual precipitation patterns such as runoff from
snowmelt), channel drying, reservoirs and dams, stream channelization, as well
as interactions with nonnative fish and decreasing water quality (Cook et al. 1992,
p. 42; Bestgen and Platania 1991, pp. 229?230; Service 1999, pp. 1?2). rather
than include "perhaps" in the statement or have another sentence addenda as
provided in the DEA and therefore, I recommend that these documents be
modified to reflect the final rule to list the species - that is, whenever water quality
declines the species responds and its habitat is degraded from an optimal
condition and indeed, whenever water quality declines sufficiently, silvery minnow
will die - its not a phenomena this species somehow skirts - certainly they are
hardy animals, but they are not immune to water quality degradation as the
qualifiers "perhaps" and "may" suggest.
This tenuousness about the health of fish (and other organisms) and the decline of
water quality should either be expressed more empirically and supported and
certainly qualified by the need for additional research. The Service could offer more
empirical data rather than "a belief" that is offered in the proposed rule, (proposed
rule, page 50920); "we do not believe it is a primary determinant of the survivability
of the Rio Grande silvery minnow in this reach (citing Edwards 2005). A review of
Edwards (2005) in context (page 26) stated: "Overall, there are some chemical
contaminants present in this reach of the river in various concentrations that may
be having negative effects on the aquatic fauna. However, because many of these
tend to have low (or lowering) levels through time, and the few studies on the
aquatic biota have not demonstrated large-scale deleterious impacts, it is not
thought that water quality is a primary determinant of the survivability of the Rio
Grande silvery minnow in the reach. Regular monitoring efforts should help in
preventing sustained impacts from chemical contaminants." In context, it is clear
that Edwards was providing a supposition, as there were no empirical studies
cited to provide support to this thought. And while water quality is identified as not
a primary determinant, this suggests the Service knows which stressor are
determinants of survivorship and therefore they should be listed in order of
importance in the DEA. Elsewhere in the document, Edwards (2005, page 11) is
more circumspect, stating, "Poor water quality from Rio Conchos inflows, loss of
the natural hydrograph and diversion (de-watering) are the primary candidates for
the loss of the species in this reach. (draft Rio Grande Silvery Minnow Recovery
Plan Update, 2004)."
Additionally, if the Service is going to depend on the improvement of "water quality
levels" as an indicator of likely survivorship of the Rio Grande silvery minnow - it
should be clear about whether and to what extent the characteristics of the
essential fish habitat that lead to the survivorship, growth, health or reproductive
success of the Rio Grande silvery minnow were measured or if any water quality
trend is a sufficient indicator. For example, if the concentration of bacteria in the
water were improved, would that indicator be sufficient to reflect the water quality
conditions that may affect the Rio Grande silvery minnow and suggest they were
also improved or has the link between bacteria as a water quality indicator not
been sufficiently linked to the qualities of the Rio Grande silvery minnow essential
fish habitat and their health and reproductive success.
That said, the Service could be more objective in its statements about the likely
impacts of water quality declines to Rio Grande silvery minnow and emphasize
the need for additional research to obtain that information. The use of the
qualifiers "may" and "perhaps" do not appear to be supported by the best available
scientific information.
Citations:
Buhl, K.J. 2002. The relative toxicity of inorganic contaminants to the Rio Grande
silvery minnow (Hybognathus amarus) and fathead minnow (Pimephales
promelas) in a water quality simulating that in the Rio Grande, New Mexico. Final
Report to the U.S. Fish and Wildlife Service, Study No. 2F33-9620003. U.S.
Geological Survey, Columbia Environmental Research Center, Yankton Field
Research Station, Yankton, South Dakota. Available from the Website -
http://www.cerc.usgs.gov/pubs/center/pdfDocs/Silvery_Minnow.pdf
Edwards, Robert J. 2005. Feasibility of Reintroducing Rio Grande Silvery Minnows
(Hybognathus amarus) to the Rio Grande, Big Bend Region, Texas. Final Report
to the U.S. Fish and Wildlife Service.