Dedicated To Tribal Aquaculture Programs
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June 1999 ~ Volume 28 | |
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Topics of Interest:
Algae and Aquatic Weed Control
Algae, Aquatic Weed Control and Management Products for Water Quality
By: Applied Biochemists, Milwaukee, WI
Aquashade: A patented, concentrated liquid formulation for use in contained lakes and ponds. EPA registered for aquatic plant growth control. Contains a blend of blue and yellow dyes to block out specific light rays critical to photosynthesis. No restrictions on swimming, fishing, irrigation or stock watering. Leaves water a pleasing blue color. Rate: 1-2 quarts per acre foot.
Cutrine-Plus Liquid: A patented, concentrated liquid algaecide with a wide range of labeled use sites. Contains chelated copper which stays in solution to continue controlling a broad range of algae well after application. No water use restrictions following treatment. Rate: 0.6-3.0 gallons per acre foot.
Cutrine-Plus Granular: A granular chelated copper algaecide ideally suited for treatment of bottom growing algae and spot treatments along docks, beaches, boat launches and fishing areas. Controls growth before it reaches the surface. Rate: 60 pounds per acre.
Weedtrine_D: A liquid aquatic herbicide that effectively controls a broad range of underwater, floating and emergent aquatic weeds. Kills quickly on contact. Ideal for small area treatments. Rate: 5-10 gallons surface acre.
Navigate: A granular aquatic herbicide which selectively controls some of the most troublesome aquatic plants such as water milfoil, coontail, and spatterdock. Gradual release and systemic action ensures complete kill of the entire plant. Rate: 100-200 pounds per surface acre.
Stockrine 2: A liquid chelated copper algaecide formula in a concentration suitable for dosing stock water tanks, troughs and small ponds. Treated water can be used immediately for stock watering. Rate: 1 oz. per 250 gallons.
Foamtrine: A silicone defoamer to suppress, eliminate and prevent foaming within a wide variety of systems. Use in pesticide spray mixtures, industrial ponds, fountains and even water park rides. Rate: As required to eliminate and prevent foaming.
An Overview of Lake Sturgeon Feeding and Intensive Culture Studies
By: William F. Krise, Martin N. DiLauro, Lori A. Redell, National Biological, Service, Research and Development, Wellsboro, PA
In the past 2 years we have conducted diet acceptance and growth studies with larval and juvenile lake sturgeon. A major part of this work has dealt with testing of experimental diet formulations and weaning from live feed to dry diets. Our results indicate that the feeding of brine shrimp (Artemia) nauplii to sturgeon larvae is a more acceptable form of culturing dependable year classes than the use of dry diets we tested, at least for the first 4-8 weeks of feeding.
After 8 weeks, we found that lake sturgeon either gained very little growth, or lost growth and condition factor unless they were converted to a dry diet during the period between 2 and 3 months of feeding. In a study where we attempted to wean fish from live to dry diets between 2-6 weeks of feeding, results were inconclusive.
Many non-feeding fish survived a long period without converting to the dry food offered, leaving two very distinct size groups. We were able to convert fish to dry diets reasonably well (best survival of 70%) beginning 8 weeks after feeding. In this experiment, fish were gradually removed from live feed dependence over 11 days before only dry diets were offered. These fish had also been fed the test diets for 6 weeks, although they appeared not to consume them.
We used commercially available diets for this study, including trout and Atlantic salmon feeds, plus Biokyowa and Biodiet. In the 30 day test, Atlantic salmon diet, ASD2-30 (U. S. Government formula) provided best conversion with good growth and 70% survival. Biokyowa was next best diet with 62% survival and lower growth. In a second weaning test where fish were instantly converted to dry diet, we had much lower survival overall (29% or less), with the best conversion to dry diet using the experimental diet formulated at Bozeman Technology Center (F. Barrows).
In the second year of tests we used Biokyowa diet and variations of the Bozeman diet to attempt to start larvae on dry feeds at their first feeding. The Bozeman diet was fed as formulated and modified in two ways, the addition of an Artemia surface coating or a softened texture using propylene glycol. The best survival of lake sturgeon larvae started on dry feeds was 10.4% using the softened diet, however this was lower survival than that for fish reared on brine shrimp (39%). In addition, the fish started on dry diets were much smaller than brine shrimp-fed fish, weighing 0.1g each versus 0.5g size for live diet-fed fish. In these experiments we were unable to find a suitable starter diet, or one which could be used for fish under 8 weeks of feeding age. We found that rearing of lake sturgeon at less than 15.0 C resulted in a much longer time to first-feeding than for fish at 15.5 or 17.0 C. This was significant because there was a long-term mortality over several months at the lower temperature. Using higher temperatures, we had very little mortality after 2 months of rearing.
Steps To Prevent Whirling Disease
By Russell Lee, Aquaculture Magazine January/February 1999
Plenty has been said in the press about whirling disease and the role of state agencies and producers in controlling it. The other group in this equation that also has some responsibility for preventing its spread is the sportsmen/fishermen. They can help prevent spread of the pathogen and aid state agencies in this effort. Below is a list of some things anglers can do to help:
1. When leaving a fishing area, drain all water from your boat, canoe, coolers. Do not move water from one water body to another. The infective stage, if present, can be transported in water to a new location.
2. Clean all fishing equipment, such as boats, boat trailers, canoes, waders, boots, float tubes, fins, truck tires of mud and aquatic vegetation before leaving a fishing area. Completely dry all equipment or disinfect with a strong chlorine solution before going to another fishing area. The spore stage is resistant to drying and can be spread by moving wet or dry mud from one site to another.
3. When cleaning your fish, do not put heads, skeletons or internal tissue in any public waters. As these parts decompose they will release the whirling disease spore, if present. Put all fish parts in the garbage or thoroughly burn them.
4. Do not transport live fish between different waters. It is illegal to move live fish unless done under a proper license and only if they have been thoroughly tested for diseases. Transport fish dead on ice (no water). Live trout that carry the pathogen can infect a new water source if they are transplanted.
Only through the cooperation and dedication of all interested parties will we be able to control and contain this persistent pathogen.
The Benefits of Liming Ponds
By James W. Avault, Jr., Aquaculture Magazine January/February 1999
Why Lime Ponds? Ponds may be limed to obtain one or more of the following benefits:
(1) Total hardness and total alkalinity are increased, and the pH buffer system is enhanced.
(2) Liming neutralizes acid soil conditions, thus increasing the pH and availability of phosphorous.
(3) Liming adds calcium, a plant nutrient. If dolomitic limestone is used, magnesium, also a plant nutrient, is added.
(4) Addition of calcium is directly beneficial to crustaceans.
(5) Liming may serve as a disinfectant.
(6) Decomposition of organic matter in pond muds is speeded up.
(7) Lime helps to flocculate (settle out) clay particles in muddy water.
Total Hardness, Total Alkalinity, and the Buffer System
Waters with a total alkalinity or total hardness of less than 10 ppm rarely produce good crops of fish. At 20 ppm production of phytoplankton may be adequate, and at 50 ppm and above, phytoplankton growth and resulting fish production is best. Liming is generally recommended when total hardness is less than 20 ppm (as CaCO3).
Arce and Boyd (1975) found that liming increased both total hardness and total alkalinity. Before liming, total hardness in 10 study ponds ranged from 5 to 14 ppm, and total alkalinity varied from 11 to 18 ppm. Several months after ponds were limed, the average total hardness and total alkalinity reached 38 ppm and 42 ppm, respectively. When CaCO3 is added to pond waters, the calcium contributes hardness, and the carbonate contributes to increased alkalinity. By increasing the alkalinity, the availability of carbon dioxide for photosynthesis was increased. Increased alkalinity also improves the buffering system against sudden changes in pH.
Liming Neutralizes Acid Soils
Addition of lime to acid pond soils increases the pH, allowing better release of nutrients, particularly phosphorus. This, in turn, enhances plankton growth and the production of organisms in the food chain. Bowling (1962) found that liming increased production of benthic organisms. The lime reacts with bottom muds and neutralizes acidity by exchanging basic for acidic ions on cation exchange sites. In instances where fertilization has proved unsuccessful, acid soil conditions should be suspect.
Addition of lime, with no fertilization, may increase production simply by allowing for the release of nutrients locked up with pond muds.
Pump Water Without Electricity or Fuel
Reprinted From: The Aquaculture News - April 1999
Since 1884, Rife Hydraulic Engine MFG. Co., Inc. has been dedicated to providing the means for pumping water uphill without the use of electricity or fuel. These pumps are ideal for fisheries since they can be used for keeping ponds full and aerated. The Water Ram, Slingpump, the Pasture Pump and the M3 Floating Solar Pump are complimentary products that can be used in almost any application.
Hydraulic Water Ram: For 115 years Rife has been manufacturing the Hydraulic Water Ram, which pumps water up to 500 feet vertically solely by means of water power. Gravity fed water powers the Rife Ram, driving a portion of that water uphill, 24 hours a day. This provides a continuous supply of water without interruption. They come in 22 different models (3/4" to 8") and can deliver up to 350,000 gallons per day (243 gpm). Two or more can be hooked up together to provide more water if needed. Rife Rams are cast iron and are one of the most durable and reliable products ever invented. There are many still working today that were installed over 80 years ago. Given a steady supply of water, the Ram is the closest thing to a perpetual motion machine. Since it requires no electricity or fuel, there are no operating costs.
Slingpump: The Slingpump is also a self-supporting system which is independent of any external power source. It can pump water up to 82 feet vertically and up to a mile away. It is powered completely by the flow of water in a creek, stream or river. The Slingpump contains a polyethylene pipe which is spirally wound on the inside wall of the body. The pump is set into a slow rotation by means of the water flow. As the pump rotates, an alternating inflow of air and water enters the polyethylene pipe inside the pump on the downstream end. As the body rotates, the alternating pockets of air and water are pressed towards the upstream end of the pump to your delivery point.
For more detail send $3.00 for a complete information package, add $10 for a video to Rife at: P.O. Box 95, Dept. AQN, Nanticoke, PA, 18634. Or call 1-800-RIFE-RAM to order by phone.
Transportation and Handling of Walleye Eggs, Fry, Fingerlings, and Broodstock
By: Richard T. Colesante, Oneida Fish Cultural Station, Constantia, New York 13044
Walleye have been propagated in North America since the late 1800s. Egg, fry and pond fingerling production programs are widespread and well documented. Recent advances in culture techniques have enabled intensive production of large or advanced fingerlings. Culturists have shipped millions of walleye within and between many states in the continental United States. The New York State Department of Environmental Conservation (NYSDEC) Oneida Fish Cultural Station has shipped walleye eggs and fry to at least 17 states. This chapter describes practices used at the Oneida Fish Cultural Station in the handling and transportation of walleye broodstock, eggs, fry and fingerlings.
Capture and transporting broodstock
At the New York State Department of Environmental Conservation Oneida Fish Cultural Station, up to 40,000 adult walleyes are handled and transported during spring netting operations. Adults are captured with trap nets on a daily basis. After capture, they are placed in tubs, 48 x 32 x 18 in, with about 40 gal of water. As many as 150 adult walleyes that average 1-3 lbs are held in a tub. They are transported by boat up to 1 mile to the hatchery, where the sexes are hand-sorted into separate holding tanks. The elapsed time from removal of walleye from nets to placement into hatchery holding tanks is 30 min. Once sorted, the fish are routinely crowded, 500 fish/150 ft3, in tanks for up to 3 d or longer if water temperatures are low, (40F). The seemingly "rough" handling for transportation and sorting is tolerated by adult fish with little mortality. The normal water temperature during the procedure is between 40 and 50F. The stripping of adult walleye does not noticeably stress the fish. Walleyes are handled using cotton gloves. The fish are out of water less than one minute while being stripped before being returned to the stream. Normally, the post-release mortality associated with the entire netting and stripping operation is less than 20 fish.
Egg fertilization and water hardening
Walleye eggs can be fertilized by either a wet or a dry method. Both produce acceptable results and preference of the culturists will probably determine the method used. Often, however, the dry method of fertilization is impractical in large field operations.
Following fertilization, eggs must be continuously stirred because of egg adhesiveness. Stirring can be accomplished with paint brushes (sized according to the volume being stirred), turkey feathers or other similar implements. To prevent having to stir eggs to the end of water hardening, most culturists treat the eggs to remove or coat the adhesive substance on the egg shell. The two most common agents are tannic acid and fullers earth, although other agents are effective. These agents are generally applied to a mass of fertilized eggs at varying concentrations, stirred for a brief time, and then poured off. After rinsing, eggs are allowed to water harden with minimal care. If not treated, egg stirring must be done throughout the water hardening process, but this can contribute to egg mortality.
Egg treatments with tannic acid can affect the color of eggs. Walleye eggs are yellowish in color and become darker as they age. When treated with tannic acid, the eggs turn from yellow to a dark brown or black (usually within three days). Although this color change may alarm many fish culturists, the treatment does not seem to reduce viability of the eggs.
Egg incubation
Following water hardening (1-2 h depending on water temperature), eggs are generally placed in Downing style jars for incubation. Three qts (2.8 L) of water-hardened eggs are placed in each jar for optimum loading density. Water flow through the jar is initially set at 1.5 gpm, but it is reduced after one day to 1.0 gpm, and then increased again at hatching to 1.5 gpm.
In large-scale operations using surface water supplies, eggs must be treated to control fungus and prevent egg mortality. A common treatment is a 1,667 ppm formalin concentration in a 15-minute flow through treatment every other day. Because formalin is not approved by the Food & Drag Administration (FDA) for treatment of walleye eggs, an Investigative New Animal Drug permit (INAD) is required. In the spring of 1994, hydrogen peroxide was tested on walleye eggs at concentrations of 250, 350, and 500 ppm active ingredient for 15 min every other day. Egg survival was similar to that achieved with formalin, however, hydrogen peroxide did not control egg clumping and clumps of dead eggs floated out of the jar and plugged the outlet during and shortly after treatment. Hydrogen peroxide is a chemical in the low regulatory priority class with the FDA, and an INAD is not required for its use.
During egg incubation, dead eggs become less dense than live eggs and move to the top of the egg mass in the jar. Dead eggs are periodically removed from jars using a small siphon. This process invariably results in the collection of live eggs as well. At the Oneida Fish Culture Station, we place the eggs siphoned from the hatching jars into a "hospital" jar where a second effort is made to separate live from dead eggs. Any eggs siphoned from a hospital jar are discarded. By the time eggs are eyed, the jars contain mostly live eggs. Routine, regular cleaning (removal of dead eggs) of jars minimizes egg clumping and fungal problems and facilitates movement of hatched fry out of the jars.
Shipping eggs
Million of eggs have been successfully shipped over the years. We have used the "dry method" for the last 20 years to ship eggs. Eggs are transported in shipping boxes with perforated Styrofoam trays, cheese cloth and ice. Eggs can be successfully shipped any time after day 5, or about 90F TU's of incubation. It is not necessary to wait until the eyed egg stage to ship walleye eggs. Prior to shipment, dead eggs are removed, water is decanted from the jar, and the eggs are poured into a tub. Styrofoam trays are covered with cheese cloth and they are floated in a tank. We add three quarts of eggs to each Styrofoam tray, then wrap the wetted loose ends of the cheese cloth over the eggs. The trays of eggs are then placed in the shipping box previously lined with a plastic garbage bag so moisture doesn't damage the cardboard. Each box, 17 x 17 x 21.5 in will receive 5 Styrofoam trays or a total of 15 qts of walleye eggs. The top tray in the box has no eggs and is loaded with ice to help maintain temperatures. The bottom tray in the box is not perforated, receives no eggs and collects moisture from the trays above. The box is sealed with tape, and the eggs can be shipped. Shipment is normally by vehicle and/or air; eggs have survived 18 h trips with no apparent ill effects.
Other methods of shipment are possible. These include placing eggs in plastic bags with water and oxygen and transporting them in a cooler. However, it is best not to ship eggs that might hatch during shipment, because eggs hatching in route could create water quality problems within the bag.
Walleye fry
In most applications, walleye fry hatch and are carried (swim) out of an incubation jar into a holding tank. The fry are about 0.3 in. They do not have an inflated swim bladder. Significant morphological and physiological changes occur as walleye are nourished through the yolk sac. The initiation of exogenous feeding occurs between 180 and 216F TU's. Fry in holding tanks are normally held at high densities. Because cannibalism can occur in first-feeding fry, one objective of fry stocking programs should be to stock fry prior to first feeding. The time window for transfer is normally 3-5 d after hatch. When stocking, fry should be harvested from holding tanks and stocked daily whenever possible.
Enumerating fry
The most common method of enumerating walleye fry involves volumetric displacement. Fry capture from the holding tank is facilitated by first concentrating fry to specific areas of the holding tank. Because newly hatched fry are positively phototactic, they will concentrate where the light intensity is the greatest. As walleye age during yolk sac absorption, their displacement value changes. Accurate enumeration requires frequent sampling.
Transporting fry
Transportation of fry is accomplished by placing fry directly in a transportation tank or by placing fry in plastic shipping bags with water and pure oxygen. Transportation tanks are usually insulated fiberglass or wood tanks with covers, and aerators, agitators and/or bottled oxygen. The size of tanks vary, but generally are around 300 gal; a single transport track might carry 6 or more tanks. Transportation of walleye fry requires that pure bottled oxygen be delivered to the water in the transportation tank. Agitators and aerators create excessive turbulence in the tank and can injure the delicate fry. Pure oxygen is usually delivered by air diffusers or rubber hose with fine holes in it. In New York, fry are loaded into tanks at a rate of one million fry per 50 gal of water. Six hours of transportation time under these conditions has no adverse effect on fry. Fry are removed by draining or siphoning them from the tank to minimize handling. If fry are stocked from a boat, siphoning, draining or bailing out of the boat tank is desirable and minimizes the use of nets.
When stocking small numbers of fry, such as those destined for earthen culture ponds, plastic bags can be used. The use of plastic bag in shipping large numbers of fry at high density has also been linked to mortality. Fry tend to settle in comers and in the bottom of the bag. Mortality can result even with adequate dissolved oxygen in the water.
NYSDEC guidelines for transporting and stocking fry:
Large stockings of more than 1 million fry:
Fry should be placed directly in truck compartments at a rate of 1 million per 50 gal of water. Oxygen should be bubbled into the compartment. The loading rate can be prorated for different capacity transportation tanks.
A. Fry should be siphoned into a live car on a boat, tempered as needed, and boat stocked in open water areas. Fry should be drained or siphoned from the live car into the lake.
B. If it is not possible to do (A), fry should be tempered on the transportation track by adding water and siphoned directly into the lake. Consideration should be given to stocking in stream currents (inlets) in hopes of carrying fry to pelagic areas.
Stocking for less than 1 million fry within 3 h of the station
A. Transportation should be as in lA or lB, if practical.
B. If not practical, fry can be transported by placing lots of 100,000 fry in a standard hatchery bag, 18 x 36 in, with 2.6 gal of water and 1.3 gal of oxygen. Bags should float freely in a hatchery tank compartment with at least 6 in of water. The truck should not stop for periods of longer than 15 min. Water in bags should be tempered by floating them in the receiving water only if absolutely necessary. It is preferable to release fry immediately into receiving water. Fry are released from the bag by opening it or cutting it with a knife and dumping the fry and water.
Small fingerlings - Handling and Transportation
Intensive culture of small (>1 in) fingerlings is relatively new. At the Oneida Fish Cultural Station, brine shrimp-fed walleye with newly inflated swim bladders (day 8 of life) have been harvested from rectangular units, transported by track and stocked. Fish were harvested by siphoning them into tubs; tubs with water and fish were poured into transport tanks with an oxygen life support system. Transportation was for 2 h, and fish were not stressed at the time of stocking.
Thirty day-old brine shrimp-fed walleyes (about 1 in long) are exceptionally sensitive to handling. When 30-day-old walleye come in contact with a net, many immediately go into shock and die. Generally by day 40, this sensitive period is over and normal handling of walleyes is possible.
Handling and transporting 1.2-2.0 in walleyes harvested from earthen ponds create a different set of problems. Many variables in a pond program can affect handling and transportation success, and fingerling survival. Among the variables are: inability to control water temperatures; the need to seine the fingerlings in many cases; contact of fingerlings with macrophytes, algae, crayfish, and aquatic insects in a concentrated situation as the pond drains; variation in condition factor of fingerlings due to problems associated with maintenance of food supply; deterioration of water quality as the pond drains. Culturists should concentrate on minimizing the effects of these variables on harvested walleyes. For example, ponds should be harvested on cool days and in the morning when possible. Algae and macrophytes, especially in the area of the kettle or catch basin, should be removed. Ponds should be harvested prior, during or immediately after zooplankton disappears to minimize deterioration of condition factor. Fish captured in the bag of a seine or corralled in a net should be removed in water with a bucket or with a hand net to minimize the contact of fish with the seine.
New York State Department of Environmental Conservation employs the following standard procedure for pond harvesting: remove fish from pond to truck with the least contact with nets as possible; drain fingerlings from truck to holding tank and hold overnight; gradually cool water to 65F; remove tadpoles, crayfish and other undesirable organisms; next morning, remove dead fish and sample fish in holding tank; load transportation truck by displacement or weight and use aerators or oxygen for life support (depending upon fish size); temper water in tank at the stocking site if the difference is 10F or more; drain or siphon fingerlings (if possible) to minimize netting at the stocking site.
Effects of water temperature on transportation and handling
Some researchers have recommended 71.6F for the intensive culture of walleye fingerlings. However, fish culturists generally attempt to maintain rearing water temperatures at 68F or less. In doing this, culturists accept slightly slower fish growth to obtain greater survival, in part because bacterial levels (and potential diseases) increase as water temperatures exceed 68F.
The primary bacterium of concern in walleye culture is Flexibacter columnaris, a ubiquitous pathogen that can cause mass mortality of walleye in hatchery environments. The transmission of columnaris has been linked to routine mechanical injury (as from handling) in fingerling walleye. This bacterium flourishes at water temperatures above 68F. Therefore, handling and transportation of walleye should occur below this temperature. When walleye must be handled at higher temperatures, such as during the harvest of pond fingerlings, extreme care must be exercised.
Advanced fingerlings
Walleye raised intensively and fed formulated diets become tolerant to handling and transportation stress. Other than common sense, such as not handling sick fish and not handling them when water temperatures are excessive, these fish can be sampled weekly, inventoried, netted, and transported using the same methods used to handle salmonids.
Loading rates in transport tanks for pond-raised or intensively-raised walleye fingerlings are similar to trout. Three-quarters of a pound of 5 in walleye fingerlings/gal of transport water are commonly used in New York.
Usually, with larger fingerlings, mechanical aerators or agitators are used to generate acceptable life support conditions in insulated transport tanks. There should be no starvation period prior to shipping as this could promote nipping and cannibalism.
The use of chemicals in transport water has been examined. Salt is commonly used to alleviate stress during transport. With walleyes, however, care should be exercised. Significant losses of pond-raised fingerlings have occurred when they were shipped in moderately hard water with salt to a soft-water hatchery. Immediately upon siphoning from truck to hatchery water, the fish went into shock and died. Other shipments from that hatchery without salt in the transport water produced no mortality.
Hatchery Tip
Are you looking for a safer way to handle formalin? Are you tired of sniffing formalin fumes and walking around in a daze? You may want to call the staff at ALab Safety@ (608-757-4738) and order a fullface respirator that is specifically designed to block formalin fumes. The MTAN first used these devices several years ago and was pleased with the outcome.
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| Product and company names mentioned in this publication are for informational purposes only. It does not imply endorsement by the MTAN or the U.S. Government. |
