Dedicated To The Tribal Aquaculture Program

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Topics Of Interest:

*  How to raise 0.4 walleyes/square foot

*  The Northern Wisconsin Aquaculture Demonstration Facility

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How to raise 0.4 walleyes/square foot

By:  Nelson Smith, Great Lakes Inter-Tribal Council Intern; Edited by Thomas C.J. Doolittle,
Fish and Wildlife Biologist, Bad River Band of Lake Superior Tribe of Chippewa Indians

Special thanks to Ed Leoso, Hatchery Foremen and the whole Bad River Hatchery Crew

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In the spring and summer of 2004, the Bad River Band of Lake Superior Chippewa Indians Fish Hatchery released over 400,000 1.2 to 2 inch walleye fingerlings into the Bad and Kakagon Rivers. The fingerlings were raised in two ponds with a total area of 160,000 ft². This article details how this was accomplished from spawning to release.

Spawning:

The walleye spawning season starts once the springtime morning water temperature of the river exceeds 40F. On the Kakagon River, this occurred on April 12, 2004, and the Bad River Fish Hatchery crew set 16 fyke nets in river segments where walleye stage, run and spawn. All nets had a 15 ft. trap, a hoop opening of 48 in., and a 2.5 in. stretch mesh. Either a 50 or 100 lead was used, depending on the location of the net. The nets remained set until April 23, 2004, during which time the nets were checked daily. Captured adult walleye were separated by sex and placed into aerated holding tanks for transport to the hatchery. Once at the hatchery, the walleye were placed into 96"X 48"X 43" holding pens that were set in the river. Each days catch was placed into its own holding pen. The 2004 fyke netting operation yielded 2,358 adult walleye consisting of 1,775 males and 583 females. Adult walleyes remained in the pens until the females bellies softened and their eggs could be easily stripped. The eggs from one or two females were stripped into a metal bowl holding about 1 inch of river water. One crewmember would then strip milt from about 10 different males into the bowl containing eggs while another gently stirred the eggs with a large feather. This was done to mimic the sexual competition that occurs in the wild and also to promote genetic diversity. After fertilization (completed in < 3 minutes), a bentonite clay mixture was added in order to prevent the eggs from clumping. The clay and egg mixtures were then placed into hardening trays and the eggs were allowed to harden in the river for several hours. After hardening, the eggs were washed over a fine mesh and transferred into bell jars.

In the 2004 season, the Bad River Fish Hatchery Crew stripped eggs and sperm from April 18 to April 26 and yielded 147 quarts of eggs.  Each quart contained about 110,000 eggs.

Hatching:

Fertilized eggs were transferred into 4qt. bell jars. One and one-half quarts of eggs were added to each jar. UV sterilized water was continuously flowed into the jars at a flow rate sufficient to keep the eggs gently rolling at the bottoms of the jars. Overspill from the jars leads into a trough, which leads to a holding tank. Water temperatures in the jars were maintained at 48 to 50 F during the incubation period, which lasts between 9 to16 days. In 2004, using UV sterilized river water, we hatched around 72% of the eggs.

After hatching, the fry swam out of the top of the bell jars and into the trough, and from there into the holding tank. The water temperature in the holding tank was maintained at 55 to 58 F. In the 2004 season the Bad River Fish Hatchery produced about 12 million fry, of which 11 million were released into the Bad and Kakagon Rivers without further rearing. The remaining 568,000 were released into two rearing ponds near the tribal hatchery on May 8 and held for 40 days.

Rearing:

The Bad River Fish Hatchery operates two large rearing ponds. One pond is 238 X 338 ft. and the other is 180 X 338 ft. The hatchery crew began filling the ponds with water from the Kakagon River on April 20, three days before the fyke nets were pulled. The ponds filled in about six days and were let alone to settle for about a week prior to fry placement. Water intakes were equipped with coarse basket screens in a screened box and outlet pipes (delivering the river) were equipped with a 200-micron screen to exclude predatory aquatic organisms from entering the ponds and still allow pioneering zooplankton to enter.

While the ponds were filling, the crew added a 10:1 ratio of alfalfa meal and B&B Brewers Yeast to the ponds. A total of 1,800 lbs (1,200 lbs in pond 1. 800lbs pond 2.) of meal was added to both ponds while they were filling to allow the additives to mix well into the ponds. One pond was equipped with AquaMats to provide cover and an additional food source for the growing fry. This pond had historic poor production and the AquaMats were viewed as one item that did augment higher productivity in the pond.

Beginning on April 24, and continuing throughout the rearing period, both ponds were tested at least twice a week for the following environmental conditions: Temp, DO, pH, Phos, and NO₃. The 2004 average values for these parameters were: Temp (61F), DO (7.55), pH (7.42), Phos (0.036), NO₃ (0.413).

In addition to the continued placement of smaller volumes of meal and yeast, we maintained a slow constant flow (10 g/m) of river water into both ponds.

There were screened outlets on the culverts to maintain a slow constant flow system. Subsequently, chemical parameters of the river and the ponds were maintained synchronously and deviated very little throughout the rearing season. We also noted that the seasonal phenology of the zooplankton flora in the river were the same in the ponds following the natural cycles needed for walleye fingerling growth. However, densities of zooplankton flora in the ponds were much higher than noted in the river. This was likely augmented by both the river inputs and fertilization. Maintaining at least a 7:1 ratio of NO₃ to phosphates was important to controlling algae blooms. Allowing water in from the river raised NO₃ levels whenever the ratio became too low. Subsequently, we have never had any algal problems in either pond, and we have had excellent zooplankton production.

On May 8, 2004, fry from the hatchery were transferred into aerated plastic bags. The bags were placed into the rearing ponds and the fry were allowed to acclimate themselves to the pond temperature before being released. Upon release, an underwater viewer was used to verify that the released fry were robust.

The ponds were tested weekly for the presence of food organisms for the fish including cladocerans, copepods, ostrcods, chronomids, rotifers, and insects. Density was determined by recording three replicate counts of each zooplankton order from three drops of water viewed through a 100x scope. Each sample was randomly gathered at each pond using one tow from a plankton net. The rearing ponds were routinely treated with a 10:1 ratio of alfalfa meal to yeast to maintain a food source for the microorganisms that feed the fry. On cold days the yeast facilitated a quicker breakdown of the meal, making more of the meal available to the food source of the fry. Fertilization only occurred on clear days and was spread along the shallow edges, creating a productive artificial littoral zone in the ponds.

In our opinion, fertilizer placement on littoral edges with yeast stimulated quick breakdown of the alfalfa. This process was further assisted since the pond liners are black, so even if temperatures were <40 F there was sufficient heat due to sunlight and yeast activity. Subsequently, cooler weather did not affect the productivity of our operation.

Predation Control:

Several steps were taken to minimize predation on the fry. An 8 ft. chain link fence surrounds the perimeter of both ponds. The fence is equipped with a 3 ft. aluminum flashing all the way around the fence. This design discouraged predators such as salamanders, frogs, and turtles from entering the ponds. All light sources within 150 yards of the ponds were removed, since the ponds are built on the edge of a large coastal wetland. In the past light sources would attract multitudes of aquatic predacious insects. Despite these control measures, some herptiles were able to enter the ponds. To minimize their effects, the ponds were walked every morning and anuran eggs were removed and, if possible, the predators themselves were captured and removed, including predacious invertebrates.

Drawdown and Release:

The drawdown requires constant monitoring and crew members were on hand around the clock.  Fish behavior is observed daily throughout the rearing season and the first sign of cannibalism in the ponds promotes an emergency draw down. However, we believe between constant observations of fish behavior, not over stocking, not keeping high densities of walleyes more than forty days and monitoring plankton densities that cannibalism can always be avoided. Usually, at the forty day mark is an appropriate time to drain the ponds and release the fingerlings. The average length for the fish was 1.4 inches. The ponds were drained, one at a time, into a catch basin. The catch basin was equipped with several aerators, oxygen tanks, as well as overhanging pipes to deliver water to increase DO levels should they fall below critical thresholds. DO levels should be maintained between 4 and 12 ppm. A HACH DO and temperature meter was used to measure DO and temperature in the catch basin at all times during the draw down period.

As a pond drains through the catch basin, the fingerlings are concentrated into it. Once there are an adequate number of fingerlings in the basin two crew members seine the basin and a third crew member waits with a pickle bucket, ready to receive the fish. Before the seining begins the bucket is filled about 1/3 full of water then weighed. After the fish are seined into the bucket it is weighed again so the weight of the fish in the bucket can be deduced. Three batches of 1,000 fingerlings were counted throughout the draw down and weighed so that the number of fish per unit mass could be estimated. The fish were then transferred into an aerated tank either on a boat for transport or on a truck for transport and release to the Kakagon River and Bad River.

 

The Northern Wisconsin Aquaculture Demonstration Facility
By:   Gregory J. Fischer, Facilities Director, 715-373-1047

 

The mission of the Northern Wisconsin Aquaculture Demonstration Facility is to promote and advance the development of commercial aquaculture in Wisconsin and throughout the Midwest. The Facility will:

1. Establish production-scale demonstration of modern aquaculture techniques.

2. Provide hands-on training for all parties interested in aquaculture including fish farmers, as well as tribal, state, and federal natural resource entities.

3. Conduct applied research projects on promising technologies and techniques.

4. Provide educational outreach, and a reference center on all aspects of the science and business of aquaculture.

The staff of the Facility will work with representatives of the aquaculture industry and the scientific community, as well as individuals from regulatory and natural resource agencies to identify industry needs, conduct training/research, and disseminate new technology information to the aquaculture industry and the general public.

We will stimulate the economic development of the industry by identifying and testing equipment, species and rearing techniques that can be used for profitable, sustainable and environmentally sensitive aquaculture. Examples of our specific objectives are:

Provide training and educational outreach to all interested parties including fish farmers, tribal entities, state and federal hatcheries.

Provide hands-on workshops on topics such as hatchery management, fish health, recirculating aquaculture, genetic strain management, pond management, harvesting and stocking protocols.

Coordinate workshops with state agencies to assist farmers in the development of business plans, capitol funding and the economic strategies of fish farming.

Conduct applied research on commercial scale aquaculture issues such as; commercial grow out feasibility for various species, intensive recirculation system evaluation, flow-thru system evaluation, pond management, weed control in ponds, effluent management issues, fish health and biosecurity on the farm, feed and nutrition testing.

Work with the industry to develop new aquaculture species and techniques, such as; aquaponics or hydroponics utilizing fish effluents, effluent management, sustainable environmentally friendly aquaculture, baitfish rearing, organic aquaculture or multi-species systems, to identify and develop production based marketing/processing avenues, explore niche markets and branding of products.

Work with state, tribal and federal agencies and the industry to provide for a cooperative interchange of aquaculture research and technology transfer.

Develop a cooperative venue for aquaculture information and contacts that is easily accessible to industry personnel.

Create partnerships with the Department of Public Instruction and local schools focused on aquaculture programs and training opportunities.

Year I (FY 05)

In this first year, our efforts have been focused on construction of the Hatchery Facility. We expect to open the hatchery facility in early spring 2005. Installation and testing of equipment and systems will be an important initial task necessary to make the hatchery functional. We will implement standard hatchery operating procedures to maintain a production scale hatchery (e.g. bio-security, monitoring of life processes, water quality, and effluent management). We will be hiring and training aquaculture and maintenance staff and planning educational outreach with local schools, colleges and universities.

We will initiate the first phase of our USDA/ARS funded commercial yellow perch rearing cooperative project.

Supervision and assistance will be provided to the general contractor for construction of the Administration/Classroom Building if funding is secured.

Year II (2005-2006)

In year two we expect to begin the following full-scale experiments and testing regimes (dependant upon funding):

Plant control and fertilization demonstration project in outdoor fish rearing ponds utilizing various methods, types and application rates.

Conduct USDA/ARS cooperative commercial yellow perch study and demonstration.

Explore feed training and profitability of various age class yellow perch.

Test "new" feeds available for coldwater species such as rainbow and brook trout with emphasis placed on health, growth, effluent and profitability.

Test efficiency of peat for effluent management use in aquaculture.

In addition, we will launch our full scale educational outreach program. We will increase educational tours, host workshops on various aquaculture related topics and make presentations at professional conferences.

Year III-V (2007-2010)

In this phase of full-scale operation we will continue the applied research projects initiated in Year II. In addition, we will explore the feasibility of select hydroponic systems and plants for both consumable and effluent management and continue the USDA/ARS commercial yellow perch study. We expect also to begin to secure extramural grant funding to help support the operation of the Facility. With more stable funding, we will be able to conduct additional projects suggested by the aquaculture industry and other partners. In this way we will achieve our overall goal of strengthening the economic position of the industry in Wisconsin and throughout the midwest.

November, 2004 Update

Phase II construction is going well and the facility is looking impressive.  The contractors are right on schedule and plan to have substantial completion by January 2005.  The tractor shed/wellhouse/headtank building and the remote wellhouse #2 building are 90% completed.  The Hatchery Barn is up and enclosed.  It will be totally closed in with windows and garage doors by the end of November.  Contractors are working to have heat and electric in the hatchery barn within the same time frame.  We are planning on testing the high capacity well systems soon this fall and are working out the effluent system permitting with EPA and the Red Cliff Tribe. 

Facility equipment is being ordered and should start arriving any time.  Tanks, piping, and related fish rearing equipment and systems are being designed and ordered for delivery in January and February of 2005.  Fish rearing systems will be assembled on site by facility personnel during the winter with a spring activation date.  Any questions or comments should be directed to Greg Fischer at 715-373-1047 or email gfischer@uwsuper.edu.

 

Pictorial Tour of the Facility
(Click thumbnail image to view a larger size picture)

		Gregory J. Fischer, Facilities Director, University of Wisconsin-Superior;  Aquaculture Demonstration Facility  ..this will give folks some idea on what we will be working on but it is not set in stone...we are open to ideas from the tribes...please contact me with any ideas for the facility.
		Hatchery Barn Complex which includes hatchery office, wet lab, mechanical room, storage rooms, and fish rearing areas.
		Inside the main hatchery building showing construction workers and equipment hard at it.
		Outdoor fish rearing ponds which include concrete collecting funnel and drain system, freshwater and airline inlets, screen and dam board slots for water management.  These ponds are capable of rearing a variety of species including fish for food, rehabilitation, and baitfish. Ponds were built in an area with an abundance of red clay which provides for a watertight seal to prevent water from draining out.
		Effluent settling basins and water control structures for holding and pretreating the facilities drain water before it is released into a local stream to supplement the stream water supply.  The ponds also can be used for rearing  fish due to the addition of screen slots, dam board slots and appropriate valving in the water control structures.
		Outdoor concrete fish collecting basin or kettle used for draining outdoor fish ponds.  Through a series of screens and dam boards, ponds can be slowly drained into the kettle which collects the fish from the ponds like a spaghetti strainer.  Fish can then be harvested from the kettle easily by several hatchery workers and loaded directly into the waiting fish truck for shipment.  This structure greatly increases the labor efficiency, health and safety issues for draining the outdoor fish ponds for both hatchery workers and the fish.
		Outdoor concrete fish rearing raceways.
		Pump house and aeration tower

 

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