Dedicated To Tribal Aquaculture Programs
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December 1997 ~ Volume 22 | |
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Topics of Interest:
3 MTAN Updates
3 MTAN Updates
By: Roger Gordon, Fishery Biologist, Iron River NFH, Iron River, WI, and The MTAN
1) The Keweenaw Bay Indian Community (Community) and the U.S. Fish and Wildlife Service (Service) are once again implementing a two year plan to bring gametes from several wild strains of Lake Superior lake trout into the Keweenaw Bay Tribal Fish Hatchery at L'Anse, Michigan.
This operation represents the second such cooperative agreement between the Community and the Service during the past two years. The Service and the tribe first entered into this agreement as a way of providing certified disease free wild trout for use in the Federal hatchery broodstock system. The Service doesn't have an isolation facility that can safely accommodate wild gametes plus raise the fingerlings without also possibly harming other lake trout operations. The Keweenaw Bay Indian Community has taken on a "Fish Isolation Facility" role that has greatly helped the Service meet its responsibilities to restore lake trout populations.
The plan calls for Service and Tribal biologists to collect eggs and sperm from wild lake trout. Fertilized eggs will be kept at the Keweenaw Bay Hatchery for hatching and rearing over the next two year period. If the fish pass a series of disease inspections they will be transferred (as future broodstock) to a Service hatchery where they will be later used to produce eggs and fingerlings for stocking into all three of the Upper Great Lakes.
2) The MTAN recently received a letter from the U.S. EPA that verified that most Tribal hatchery programs do NOT need settling basins. The letter we received includes the following.... "New [Tribal hatchery] facilities should apply for a National Pollutant Discharge Elimination System permit 180 days prior to beginning of any discharge. We will be happy to supply the tribes with applications as needed. In addition, for facilities that have a maximum capacity of 6000 lbs. of fish per year and use a maximum of 2000 lbs. of food per month, construction of settling ponds would not be routinely required. However, we do recommend that during the design phase, space be set aside for a settling pond in case the maximum capacity is increased or if the discharge is having a impact on the receiving stream."
3) The MTAN and Tribal hatchery stocking information are now available on the Internet! The MTAN has been busy attempting to broaden our objective of distributing fish culture information to Tribal aquaculture programs. This information is now available to visitors of the U. S. Fish and Wildlife Services, Ashland Fishery Resources Office home page.
Big Redd Incubator Problems
By: Gregory J. Fischer, Hatchery Manager, Red Cliff Tribal Fish Hatchery, Bayfield, WI
The Red Cliff Tribal Fish Hatchery (RCTFH) has some older style Big Redd Incubators that have been in use for about eight years. The incubators have usually worked well enough for the hatchery to incubate and hatch out several million walleye eggs every year. Except for occasional problems causing small egg losses, there had only been one instance of complete incubator failure causing catastrophic egg losses in the early 1990's.
During the 1997 spring walleye egg incubation period, the RCTFH experienced some problems with the Big Redd Incubator Systems that were being used. Walleye eggs collected during spring tribal spearing were placed into 760 mm tubes at the recommended level of one liter per tube (Big Redd Incubators Operation Manual). Initial incubation of eggs went as planned and hatching commenced as predicted. The fry seemed in good shape and all parameters within the incubators were within the specified limits. Due to a snowstorm and dropping temperatures, fry were not stocked into the rearing ponds on the selected date. Fry were held until pond temperatures stabilized in the Big Redd Incubator Units. During this holding time, all the fry died within a 24 hour period approximately five days after hatching commenced. All parameters within the incubators were within specified limits.
It was later determined that incubator failure was probably caused by the bottom manifold becoming restricted with particles and slime from the hatching eggs. This manifold was thoroughly cleaned before incubation procedures were initiated. There is not an effective way to clean out this manifold after eggs have been added to the incubator tubes that we are aware of. We would recommend decreasing the maximum amount of eggs added to each incubator tube and to carefully "flush" out the system during or immediately after hatching.
After losing all the walleye stock for the 1997 season, I began calling other hatcheries for "extra" fry. The St. Croix Tribe Fisheries Division donated 100,000 fry of the appropriate genetic lineage for our Eau Claire Lake Chain walleye rearing program. The Wisconsin Department of Natural Resources-Woodruff Fish Hatchery donated 200,000 fry for rearing by our conservation club cooperators. The Minnesota Department of Natural Resources-Knife River Fish Hatchery donated 100,000 fry of the appropriate genetic lineage for our Lake Superior walleye program. Many thanks go out to these departments for coming to our rescue! Without these walleye fry it would have been a very slow summer.
If there are any questions or comments on the Big Redd Incubators or the Red Cliff Tribal Fish Hatchery programs feel free to call me at (715) 779-3728 or E-mail me at gfischer@win.bright.net
A Test for Anesthetizing Hatchery Brook Trout with Sodium Bicarbonate and Glacial Acetic Acid
By: Henry Quinlan, U.S. Fish and Wildlife Service, Ashland Fishery Resources Office, Ashland, WI
The U.S. Geological Survey - Great Lakes Science Center (USGS-GLSC) and U.S. Fish and Wildlife Service - Ashland Fishery Resources Office (USFWS-Ashland FRO) are preparing to study morphometric differences of brook trout at Isle Royale National Park using the Truss protocol. This protocol requires fish be photographed and therefore motionless for up to a minute. A test was conducted at the Red Cliff Tribal Fish Hatchery (RCTFH) to determine the efficacy of an anesthetic technique using sodium bicarbonate (NaHCO3) and glacial acetic acid (CH3COOH) to immobilize fish, but allow safe consumption immediately after release (Prince et al. 1995). The objective of the test was to determine if these results could be duplicated and if the immobility attained was suitable for our purposes. This test was conducted by Chuck Bronte (U.S. Geological Survey - Great Lakes Science Center), Greg Fischer (Red Cliff Tribal Fish Hatchery), and Henry Quinlan (U.S. Fish and Wildlife Service - Ashland Fishery Resources Office).
Following the procedures described, we conducted six trials using different concentrations of sodium bicarbonate and glacial acetic acid to anesthetize brook trout. The ratio of sodium bicarbonate to acetic acid remained the same for five of the six trials and was based upon the effective ratio described. The sixth trial had a higher ratio of sodium bicarbonate to acetic acid. The fish used in this test were hatchery reared age 2+ Nipigon Lake strain brook trout raised for broodstock by the RCTFH.
Methods
The source of water at the RCTFH is groundwater and water chemistry parameters remain constant for long time periods. Dissolved oxygen (11.1 ppm) and temperature (7.2C) were measured in one raceway prior to initiating tests and were assumed to remain constant throughout the study.
A circular tub was filled with 30 liters of water from a raceway. The initial pH of the tub water was measured and recorded. The sodium bicarbonate was weighed to the nearest gram (g) and dissolved in one liter of tub water. The acetic acid was measured to the nearest milliliter (ml) in a graduated cylinder and mixed in another liter of tub water. Each bucket was then added to the 28 liters of water in the tub and thoroughly mixed. The pH of the tub water was also measured once during each trial.
Brook trout were placed into the tub and visually observed or periodically checked by hand for activity and movement. Three brook trout were used for each trial. No selection was made for specific fish and age of all fish used was 2+. Notes were kept on fish activity and length of time exposed to the anesthetic. Fish remained in the anesthetic until it appeared that no further anesthesia would occur. At the end of each trial the fish were measured, weighed, and isolated in the raceway of origin for 24 hours to check for mortality or incomplete recovery.
Results
The fish responded to the anesthesia after about 5 seconds in the tub. The fish become hyperactive for up to one minute, after which intermittent bursts of activity occurred for up to 8 minutes. Total time in anesthesia ranged from 8 minutes in trial 1 to 13 minutes in trial 6. Upon handling of the fish for length and weight measurement at the end of the trial we determined whether the level of anesthesia was sufficient for project purposes. In one of six trials (trial 5) the fish attained the level of anesthesia required for photographing. In trial 4 the fish were immobilized for brief periods that may or may not have been sufficient for the project. Fish in trials 1, 2, 3, and 5, did not reach the level of anesthesia necessary for project purposes.
As suggested by Prince et al. (1995), the amount of acetic acid will have to be modified to achieve a similar level of immobility if pH of the water is outside the range of their study (7.5 - 8.4). This also pertains to these trials in which pH ranged from 6.6 to 7.0.
Fish recovered to a normal swimming or resting position about 5-20 minutes after being returned to the raceway. For trials 3-6 there appeared to be a period of immobility for a few minutes after fish were returned to the raceway. After one week no fish mortality occurred.
We confirmed that this technique produced the level of immobility suitable for our purposes. The mixture of 60 g of sodium bicarbonate and 23 ml of acetic acid in 30 liters of water at a pH of 6.8 sufficiently anesthetized fish for protocol photography.
Comments
The process of preparing the anesthetic solution was simple and quick and is suitable for field application. Pre-weighed, packaged sodium bicarbonate could eliminate the need to weigh it in the field. The quantity of acetic acid will vary with differences in water pH. These differences will need to be addressed in the field.
Fry Culture Technique Successful
By: Dr. Gerald M. Ludwig, Research Information Bulletin, Fish Farming Experimental Laboratory, U.S. Fish and Wildlife Service, Stuttgart, AR 72160. (501) 673-4483
Culture of fishes including the striped bass and its hybrids, walleye, true basses, and many of the endangered or threatened fishes that begin as small fry or larvae require special production techniques and extremely small zooplankton organisms for food. Commonly, the culturist endeavors to produce these zooplankton when needed by a special regimen of pond filling and fertilization to make the desired number and sizes of zooplankton available when the larvae are ready to feed. More often than not, these organisms are not available when required resulting in 90 to 100% mortality of the fry, probably the result of starvation.
Many factors and conditions can affect the availability of the required food organisms. Water temperatures and changing weather conditions are the most obvious, but even altered shipping schedules or delayed spawning of the broodfish can make the best plans go awry. However, controlled production of the larvae in indoor troughs and offering the larvae cultured organisms of the particular sizes required can overcome many of the outdoor production variables.
We chose to grow the freshwater rotifer Branchionus calyciflorus as the food organism because of its small size, ready acceptance by larvae fishes, and potential for economical culture in large numbers. The sunshine bass (hybrid of the male striped bass and the white bass) was selected because of the extremely small size and fragility of the fry, and being commercially-produced the fry were readily available for our use. Thus successful growth of the sunshine bass in tanks and their being fed cultured rotifers would prove the suitability of this technique for the improved production of larvae fishes of the several species important to the nation's preservation and restoration programs.
Freshwater Rotifers Cultured With Micro Algae
Resting cysts of freshwater rotifers Brachionus calyciflorus were hatched in deionized water in small containers and then transferred to larger vessels as their populations increased. Upon hatching, the rotifers were fed microalgae, Nannocloris oculata, that had also been activated in deionized water, fertilized with Guillard's F/2 formulation, exposed to intense light, and progressively transferred to larger vessels. Rotorich (a yeast-based food fortified with a vitamin mixture, microalgae, and essential trace nutrients) was used in the larger cultures to supplement the microalgae. Average culture temperatures were 26C. Total ammonia levels in the rotifer cultures were kept below 5 mg/l by changing water and by using bags of zeolite to absorb the ammonia. The mean maximum daily standing crop of rotifers obtained in the largest cultures (70-l) was 380 rotifers/ml while the average daily concentration of microalga in 200-l vessels was 2.9 million cells/ml.
Survival and Growth of Fry Determined
The survival and growth of sunshine bass fry that were fed rotifers and later commercial fry starter meal was determined. Fifteen hundred 5-day-old fry, obtained from a commercial breeder, were stocked into each of five (round) tanks filled with well water and kept under dim light. Average daily water temperatures were 23C. Live rotifers were strained from their cultures and added to three of the tanks each morning to return the rotifer concentration to 20/ml (1.53 million/tank). Rotifers were offered from day 5 through day 27. On day 16 until day 27, the diet was supplemented by offering 3 times daily a 45% starter meal formulated for salmon. Frequency of the addition of salmon meal was increased to 8 times daily from day 27 until the study was concluded on day 41.
Rotifer Fed Fry Fare Well
The survival rate of the bass fry that were fed cultured freshwater rotifers averaged 21.2% at day 20 and 20.6% by day 41 compared to the 10% average in managed ponds. However, the trough-cultured fry grew slower and reached only about 33% of the size of the pond reared fish at the end of the 41 days. Possibly the slower growth rate was the result of a higher standing crop in the troughs due to the greater survival, and that this difference could be eliminated by additions of more rotifers and feed.
The high survival rates indicate that raising sunshine bass fry in tanks with cultured freshwater rotifers is a feasible alternative to growing the fry in ponds. Successful culture of the very tiny and fragile sunshine bass fry by the use of cultured freshwater rotifers suggests that this technique is applicable to endangered or other species where it is desirable to constantly monitor and protect the fry.
Cold Water Feeding of Trout
By: Aquaculture Magazine, January/February 1995
There are several things Dr. George W. Klontz, Professor-Emeritus of Fisheries at the University of Idaho, and other specialists recommend you do for cold water feeding. Some of the benefits of their recommendations are: better feed conversion, less wasted feed, more even growth, a higher quality product and more profits. The following tips are a summary of their recommendations:
Double Vitamins
Many nutritionists recommend using feed containing a "double vitamin pack" during periods of low feed intake due to cold water (below 45F) temperatures. This can usually be obtained upon request from your feed manufacturer.
Smaller Pellet Size
Since trout are feeding less aggressively during winter months, tests have shown that dropping back one pellet size is beneficial. The largest size feed for the larger fish should not exceed 1/8". This will insure that more fish get their share of feed which later results in less size variation.
Feed Slowly
Obviously, cold temperatures cause fish to feed more slowly. Watch the fish while you feed them to make sure no feed falls to the bottom. This ensures that less feed is wasted and that there is less accumulation of unwanted waste in the raceways.
Feed By Mid-Day
When water temperature will be dropping into the 30's at night, all feeding should be completed by mid-day. Feed when the water temperature is rising, not when it is dropping in the late afternoon. The feed will be utilized more efficiently because the initial digestion can take place before the digestive activity is greatly reduced by colder temperatures. Reduce or withhold feed the day before a strong cold front is forecast, which has the potential of dropping the water temperature ten or more degrees Fahrenheit within a few hours.
Alternate Feeding Days
When water temperatures remain in the 30's for several days or weeks, some specialists recommend feeding every other day in order to obtain a better feed conversion and to reduce labor. Feeding every day when the metabolism is so low pushes the feed through the digestive system too fast for maximum utilization.
Hatchery Tip
By: MTAN
Hatchery Supplies:
Looking for some rearing tanks, feeders of other hard to find equipment for your fish hatchery program? One of the references that the MTAN often looks to is the "Aquaculture Magazine." You can start your subscription by calling 704-254-7334 or reach them on the Internet at www.aquaculturemag.com.
Transport or Hatchery Tanks:
Peterson Fiberglass, 300 Stariha Dr., Shell Lake, WI 54871, 715-468-2306
Tubcraft, Baraga Industrial Park, Barage, MI, 906-353-7544
Reiff Manufacturing, Rt. 4-183, Walla Walla, WA 99362, 800-835-1081
Lance Industries, 4012 NC Hwy 304, Bayboro, NC 28515, 919-745-4146
Aquaneering, 619-296-5330.
Tank Water Heating System:
Cleveland Process Corp., Homestead, FL 33030, 800-241-0412.
Micro-Optics, 800-776-1771.
New Fish Feeder:
The MODEL 150 feeders by Water Management Technologies are designed to deliver various feeds from starter through d" pellets. The feeder quietly delivers feed in a 360 degree pattern, up to 30' diameter. It features an adjustable metering plate and speed control. The MODEL 2000 feeder features an adjustable speed control and is designed to deliver various feeds (starter through 3/8" pellets), medications, and treatment chemicals. The feeder delivers feed from just a few grams per day up to many pounds per hour. This unique feeder can be quickly converted from a drop delivery to a broadcast delivery with the optional MODEL 200 broadcast attachment. It is ideal for raceways, ponds, and tanks.
The MODEL 1000 timer offers 96 on/off switch actuators, controlling up to 96 (15 minute) feeding periods per day. It can control up to two Model 150 Maxi broadcast feeders or Model 2000 Accu-feed auger feeders. It features a fully adjustable repeat-cycle to provide precise control of feed and pause rate for intermittent feeding cycles. It features adjustable feeding periods from 1 to 60 seconds, and adjustable pause times from 1 to 60 minutes. For more information call 504-627-3930.
Feed Sizes for Trout
By: Skip Thompson
Feeding the correct feed size to trout is as important as feeding the right amount. Incorrect feed size results in poor feed conversion and substantial fish size variation. If the feed size is changed too soon, many of the smaller trout are left behind. If allowed to continue, this can potentially result in cannibalism as the larger trout reach a size where they can eat the smaller fish.
As trout fingerlings grow, the feed size which they can consume obviously increases (see table below). To make informed decisions of when to change feed sizes, sample counting is a necessity. Attempting to visually determine the size of the trout is often misleading, resulting in poor fish performance.
Converting the trout to a larger and cheaper feed size seems to make good sense. However, prematurely changing feed sizes based on the cost of the feed without consideration to performance is not a good business decision. Sample counting to check the size of the fish before making the feed change is good business.
If the sample count is close to the size specified for the next feed size, keep the trout on the smaller feed for another week or two. This will allow the smaller trout to grow to a suitable size for the next feed size. If there is already a large size variation in a group of trout, grading may be the best option. Remember to base your management decisions on what is best for the trout and not what is easiest for you.
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