Ashland NFWCO
Midwest Region

MTAN Home Page


Dedicated To The Tribal Aquaculture Program

June 1997 - Volume 20

 

Administrative Coordinator:

Frank G. Stone (715-682-6185) Ext.12
U.S. Fish and Wildlife Service

Email:
Frank_Stone@fws.gov

Edited By:

Elizabeth W. Greiff (715-349-2195)
St. Croix Tribal Nat. Res. Depart.

Email: 
bethg@stcroixtribalcenter.com


Topics Of Interest:

Tribal Fish Hatchery Programs Find ANew Home On The WWW

Fish Transportation Methods Usedon the Leech Lake Reservation

Coaster Brook Trout Eggs

Aeration May Consume More Than 50% OfYour Total Electrical Energy

Air Lift Systems Used To RecirculateWater

It Takes A Lot More Than A Few Bubbles ToDo It Right

Pure Oxygen or Aeration

Incubationof Walleye Eggs at Garrison Dam National Fish Hatchery

Arctic Char Culture in Wisconsin

The RightEquipment and Technology To Raise Fish for the Future

Hatchery Tip

Tribal Fish Hatchery Programs FindA New Home On The WWW

By: MTAN

Knowledge of Native American fish hatchery programs will soon be available to thepublic via the World Wide Web (WWW). Several months ago the MTAN posed the followingquestion to the Tribal hatchery programs who take our newsletter, "The MTAN wouldlike to request your consent to include information regarding your Tribal hatchery programon the Internet." The response we received was an overwhelming YES!

The MTAN has always believed that the more a person knows about any given issue, themore intelligent decisions and options they could choose from. This has been a majordriving point in the MTAN newsletters. People who have access to the Internet will now beable to read of the Tribal commitments to the resource and of the many accomplishmentsmade from Tribal fish hatchery programs.

A new Internet access link has been included in the Ashland Fishery Resources Office(FRO) Home Page. To access this information just add the following address on your URLaddress line and let your Internet provider do the rest.

Ashland FRO Home Page: http://www.fws.gov/midwest/ashland

Tribal Fish Hatchery Programs of the Northern Great Lakes Region - Giving SomethingBack to the Resource: http://www.fws.gov/midwest/ashland/tribal/

Previous issues of the MTAN and Tribal fish stocking accomplishments are two otheradditions that will soon be added to the Ashland FRO Home Page. If you have not had theopportunity, please visit this site and give the MTAN your feedback. If you would like tosee additional fish hatchery related information posted on the Internet, give a call toFrank Stone (715-682-6185) to discuss what you have in mind.

 

Fish Transportation Methods Usedon the Leech Lake Reservation

By: Steve Mortensen - Fish and Wildlife Biologist, Leech Lake Reservation, Rt. 3, Box100, Cass Lake, MN, 56633, 218-335-8240

Fish-rearing facilities across the country have made great strides in developingmethods of rearing high-quality fish for stocking. These efforts, and a great deal offinancial investment, are sometimes wasted if transportation methods do not deliver thesefish to their final destination in good condition. I have often wondered what percentageof the fish stocked each year arrives in such poor condition that they do not survive thestressful transition to their new environment. This has some serious implications,especially when we try to make objective evaluations of the success of our stockingefforts.

When you get a poor return on a stocking program is it because of poor rearing methods,poor genetics, inability of hatchery fish to adapt to the wild, or poor transportationmethods? I would be willing to bet that in more cases than we care to admit, it is due topoor transportation methods resulting in the fish being half-dead before they ever hit thewater. Over the past 14 years that the Leech Lake Reservation hatchery has been inoperation, we have tried a variety of methods of transporting fish and have come to theconclusion that the methods outlined below are the best for the species we normallytransport. For fingerling transport we use insulated fiberglass tanks, mounted on aone-ton truck, that have provisions for mechanical agitators and supplemental bottledoxygen. It only took one or two trips to realize that the agitators in the tanks werecausing far too much turbulence, which frequently resulted in pinning fish to the dividerscreen in the tank. Although agitators may work fine for strong-swimming species liketrout and salmon, the fish we normally haul (lake whitefish, walleye, lake herring, bass,panfish, and white suckers) do not fare very well under these conditions. Agitators alsocause a great deal of foaming in the tanks, which may contribute to rapid water-qualitydegradation. For these reasons we no longer use agitators while transporting fish.

Ideally the size of the bubbles being diffused into the water should be as small aspossible, as this greatly increases the amount of oxygen retained in the water. To providethe aeration the fish need during transportation we now use only bottled oxygen. Oxygen isdelivered to the fish tanks from a commercial oxygen bottle available from any weldingsupply store. It is passed from the regulator on the bottle through flow meters todiffusers in each compartment in the tank. A wide variety of diffusers are available onthe market and their efficiency, life expectancy, and cost varies considerably. The fusedglass diffusers are some of the least expensive, but many of them are designed forapplications with low pressure, high volume air flow. As a consequence, they do a poor jobof diffusing bottled oxygen into the water.

There are some very good diffusers on the market designed for use with oxygen, but theyare very expensive--up to several hundred dollars--and some of them are very fragile. Inaddition, all diffusers seem to have the problem of getting clogged with slime and algae;this decreases their efficiency and necessitates frequent cleaning or replacement. Thereis, however, a rugged, cheap, and efficient material that you can use for diffusion, andit is probably available at your local hardware store. It's soaker hose, designed to allowwater to slowly ooze through it for watering your garden. This material produces a finemist of oxygen bubbles almost as fine as the expensive diffuser stones. When the soakerhose becomes damaged or clogged we simply replace it.

The transport tanks we use are about 4 feet long and in the bottom of each we put 2lengths of hose, each about 3 feet long. This hose readily floats, so you have to weightit down or attach it to the bottom. We place a length of 3/8-inch metal rod inside eachhose to keep it on the bottom of the tank. Stainless steel is the best material to use forweight as it will resist the corrosion and oxidation conditions from the combination ofwater and pure oxygen inside the soaker hose.

By weighting the diffusers rather than permanently attaching them they can be liftedout of the tank during fish removal, which reduces damage to the diffusers, your dip netsand, most importantly, your fish.

When harvesting natural ponds, fish must be removed from the fyke net and hauled byboat back to the transport truck. For this situation we carry a small oxygen bottle withdiffuser in the boat. A small livestock watering tank in the boat is used to transportfish from the pond to the transport truck. This increases the efficiency of pond harvestby reducing the number of trips you need to make back to the truck and keeps the fish inbetter condition.

Something else we do anytime we handle or transport fish is to do so in a weak saltsolution. We think this is very important and won't handle fish without it. A saltsolution of 0.5% by weight (about 19 grams of salt per gallon of water, or 4 lbs. of saltper 100 gallons of water ) works well for us. This should be un-ionized salt; we buy agood grade of cattle salt in 50 lb. bags for this purpose.

One more method we use, for transporting fry or small fingerlings, is to place them inlarge, heavy-duty plastic bags with water and oxygen in them. We use flat-bottomed, clearplastic bags that will hold about 15 gallons of liquid. Using this method, one plastic bagis placed inside another to give us backup should the inner bag rupture. This double bagis placed inside a Styrofoam cooler and about 2 liters of water added. This may not seemlike much water, but for fry or small fingerlings you don't need much. The water onlyfunctions to keep the fish wet and transfer oxygen to their gills. Next, the fry or smallfish are added to the bag. We transport up to 1 liter of fry per bag using this method.Once the fry are added, the top of the bag is gathered up and pushed down to force all theair out. The oxygen hose is inserted into the top of the bag and the bag is filled untilunder slight pressure or until it fills the volume of the cooler. The top of the inner bagis then twisted shut, folded over, and an "elastrator" ring placed around it.The second bag is twisted shut and a second ring placed on it. Elastrator rings and thetool to install them are available at most farm supply stores. These rings are quick toinstall, give a good seal, and are easy to remove. Rubber bands can also be used. Once theouter bag is sealed the cooler is closed and the cover secured for transport. These arethe methods we most frequently use for transporting fish. They have worked well for thespecies we deal with, and we hope that you will be able to apply some of them at yourfacility.

 

Coaster Brook Trout Eggs

By: Gregory J. Fischer, Tribal Hatchery Manager, Red Cliff Band of Lake Superior,Chippewa Indians, P.O. Box 529, Bayfield, WI 54814

The Red Cliff Tribal Fish Hatchery has developed a broodstock line from three yearclasses of Nipigon Lake strain brook trout, commonly referred to as "coasters".This broodstock was developed with the cooperation of the Dorian Fish Culture Station inOntario, Canada. Presently, this is the only broodstock of Nipigon Lake strain brook troutavailable in the United States. We are expecting that the Red Cliff broodstock will becapable of producing eggs this fall to assist with any restoration or stocking plans of"coaster" brook trout in Lake Superior. For more information contact Gregory J.Fischer at the Red Cliff Fish Hatchery (715/779-3728).

 

Aeration May Consume More Than 50% OfYour Total Electrical Energy

By: Aquatic Eco-Systems, Inc., 1767 Benbow Court, Apopka, FL 32703, http://www.aquatic-eco.com, 800-422-3939

Aeration can be accomplished by mechanical aerators or underwater air diffusers.Mechanical aerators agitate water to produce liquid/air contact, while underwaterdiffusers introduce bubbles from a depth to achieve oxygen transfer and mixing. Bubbletype aeration systems are replacing many mechanical aerators because of their lowmaintenance, reliability, safety, flexibility and overall efficiency. They excel in manylocations where small amounts of aeration are needed. Bubble aerators are also better atremoving gases such as ammonia and carbon dioxide. Diffusers are made to deliver eithercoarse (approximately 6 mm), medium (approximately 3 mm), or fine (approximately 1 mm) airbubbles.

Coarse-bubble systems require the lowest air pressure and are very resistant toclogging, but are about a third as efficient as medium bubble systems in transferringoxygen to the water. The medium bubble diffuser requires only slightly higher airpressure, but its superior oxygen transfer more than compensates for the increase inmaintenance due to occasional clogging. The fine-bubble diffuser's superior oxygentransfer usually does not compensate for its higher pressure requirement and much morefrequent clogging. Fine-bubble diffusers therefore are typically chosen for pure oxygen orozone systems where pressure requirements are usually less important than transferefficiency. Overall, however, medium-bubble diffusers are the most popular amongaquaculturists.

Diffuser clogging often occurs from the inside. It's caused by dust and dirt particlescarried in by the air supply or by impurities in the water. Calcium carbonate often formsa deposit which clogs the pore outlet. (This source of plugging is prevalent in hard waterand salt water.) Another source of plugging is bacterial slime which forms on the externalsurface of the diffuser. Replacing medium and fine-bubble diffusers with coarse-bubbletypes might seem like a good way to avoid periodic cleaning, but it's not very costeffective. Let's work out the economics on a 10 horsepower system:

If a 10-horsepower medium-bubble aeration system can support 40,000 pounds of fish, acoarse-bubble system would require 30 horsepower under the same conditions. Assuming thatelectricity costs about $60 per horsepower per month. This would make the utility costrise from $600 a month to $1,800. That's an extra $14,400 per year paid to the powercompany. An additional 20 horsepower in blowers would need to be purchased as well as alarger diameter air distribution pipe if coarse-bubble diffusers were chosen over mediumbubble diffusers. Diffuser placement should allow for easy removal and time should beallotted to clean all the diffusers in one section at one time. This not only reduces theaggravation created by multiple individual cleanings, but it also suggests when toschedule the next cleaning.

 

Air Lift Systems Used ToRecirculate Water

By: Aquatic Eco-Systems, Inc., 1767 Benbow Court, Apopka, FL 32703, http://www.aquatic-eco.com, 800-422-3939

Air lifts are most efficient when moving water from one place to another within a watercolumn. They become less efficient as the water is lifted higher above the surface. Forour purpose here we will split them into two categories:

  • water moving air lifts and
  • water lifting air lifts.

Water is heavy when it is in the air but it weights no more than the water around itwhen it is in the water. A water moving air lift will then transfer water within the pondor series of tanks with very little compressed air (energy). lt just needs energy toaccelerate and overcome friction. The more air that is injected, the more water will bemoved. In an unconfined air lift, you don't even need a pipe. Even a simple airstone withits mass of rising bubbles circulates a lot of water.

When trying to lift water very high with a water lifting air lift, you'll discover thata water pump soon becomes simpler and more efficient than an air lift in terms of energyconsumption. However, raising water only slightly above the surface can be done easily andeconomically with only a small amount of compressed air.

Water Lifting Guidelines:

1. Do not use an air diffuser. Large bubbles work best as they reduce water slippage.Air injecting collars can improve the performance as much as 10% on short pipes, but theytypically are not worth the installation and maintenance difficulty. Inject the air 28-30inches below the water surface.

2. Smaller pipe diameters work best. If more water is needed use multiples of smalldiameter pipes. A sweep type extension works better than an elbow.

3. Tie a float device to the top of the outlet pipe. If additional stability isrequired, tie the top of the pipe to the shoreline. A 20 acre pond would require a 1HPcompressor.

How Does It Work?

1. The water volume (in the pipe) is displaced with the rising air bubbles, making thewater lighter. The total weight (pressure) within the pipe is less than the weight ofwater (pressure) outside the pipe.

2. Since water seeks its own level by virtue of its weight (and its fluid nature), itwill rush up an air lift pipe because there the weight is less.

3. Ever hear the phrase, 'Wind doesn't blow, it sucks"? It's true. The directionof flow (air or water) is from an area of high pressure to low.

 

It Takes A Lot More Than A Few Bubbles ToDo It Right

By: Aquatic Eco-Systems, Inc., 1767 Benbow Court, Apopka, FL 32703, http://www.aquatic-eco.com, 800-422-3939

Most lakes cover vast areas and contain millions of gallons of water. So a few randomair bubbles rising from the bottom just isn't enough to satisfy the average lake's needfor oxygen. But use that same small volume of air to induce a significant rising currentand the air becomes the driving force for an extremely efficient lake circulator aerator.One method to induce water to turn over within a lake is with the use of SynergisticDiffusers. This unique diffuser is specifically configured to allow bottom water to enterthe upwelling current with no turbulence or bottom erosion.

The 4 square foot diffuser assembly creates a vertical current using the rising forceof air, moving low oxygen water up from the bottom and eliminating any stratification. Thesystem is simple and maintenance free. As little as horsepower can be used to aerateand destratify a eutrophic 10 acre lake.

Technically Speaking:

When oxygen levels are low, you can expect transfer performance of more than 10 poundsof dissolved oxygen per horsepower. Pumps, fountains and "bubblers" aretypically less than 2 pounds per horsepower.

Bubbles expand and spread out as they rise. The column of water entrained within thebubbles from a synergistic diffuser rises at about a foot per second, moving 2,000 gpmfrom the area above the diffuser. (A drilled pipe diffuser with the same air volume wouldonly move 200 gpm.

The surface boil - created by the kinetic energy, rises approximately two inches abovethe surrounding water level. From there, the water rushes outward until its energy hasdissipated, sometimes traveling more than 100 feet, depending on temperature, surfacetension and wind.

The lake surface tension is ruptured in this boil area. Supersaturated gases from thelake bottom escape, including carbon dioxide, hydrogen sulfide, ammonia, while oxygen isabsorbed. There's no danger to swimmers, boaters or aquatic life - even a marking buoy isunnecessary. It's best to install the system prior to stratification.

 

Pure Oxygen or Aeration ?

By: Aquatic Eco-Systems, Inc., 1767 Benbow Court, Apopka, FL 32703, http://www.aquatic-eco.com, 800-422-3939

Aerators that spray water through the air or put bubbles in the water can economicallyraise the oxygen content to 75 percent of saturation. Pure oxygen becomes moreeconomical if your aquaculture program requires raising oxygen levels to saturation orsupersaturation.

Pure oxygen can be a very cost-effective tool for raising fish. It can unclutter theculture tank, reduce suspended solids, improve feed-conversion ratios and reduce stress.When used in large intensive culture systems, liquid oxygen can be purchased at a lowprice. It's especially cost effective when used to raise the ambient dissolved oxygenabove the normal saturation level.

But, you don't have to use a high-tech approach if a low-tech one will do. Simple oldfashioned aeration (done correctly) will give you one pound of dissolved oxygen (at 75% ofsaturation) for about one kilowatt of energy. That's about 8 cents per pound. Can you buypure oxygen that cheap? If you can, will 100 percent of it be absorbed, or will you losesome through escaping bubbles, leaks? Is a water pump or other energy source required?

A 1 horsepower water pump just by itself can burn another 8 cents per hour. However, ifyour operation is large enough or intensive enough to warrant aerating with pure oxygen,it can be a great tool when used wisely. Here are a few tips:

Be sure to total all your pure oxygen costs when figuring cost effectiveness, includingstorage vessel rent, water pumping cost and oxygen loss. If you're thinking about makingyour own oxygen, include the actual cost of compressed air and amortized equipment costplus repairs.

Use a saturation technique that is 80 to 100 percent efficient.

Inject supersaturated water over a wide area to prevent large oxygen gradients in thefish tank.

In a recirculating system you will still need to aerate or degas to lower carbondioxide levels.

 

How to Clean Diffusers

By: Aquatic Eco-Systems, Inc., 1767 Benbow Court, Apopka, FL 32703, http://www.aquatic-eco.com, 800-422-3939

The Sweetwater air diffusers, made of glass bonded silica, are virtually indestructibleand will give many years of service. The only maintenance normally required is periodiccleaning. The frequency of cleaning will be determined by the mineral and organic contentof the water in which the air diffusers are used. In clean, cold, soft water conditions,cleaning may only be necessary every 2 or 3 years. In very hard water or water high inorganics, cleaning may be required every two months.

The Diffusers Are Normally Cleaned in the Following Manner:

1. Remove from service and blow out excess water. If fouled with barnacles or othergross foreign material, scrape or hose them off.

2. Immerse completely in undiluted muriatic acid for a sufficient time to dissolve theclogging material. This may take from one minute to eight hours in the most extreme cases.Be very careful when using acid! Wear eye, face and hand protection and have clean wateravailable for rinsing and acid diluting in the case of an acid splash or spill.

3. After the clogging material has been dissolved, rinse thoroughly before reuse.

4. Discard the used acid by first diluting with at least four times as much water asacid there by reducing its strength to a neutral pH.

 

IncubationOf Walleye Eggs At Garrison Dam National Fish Hatchery

By: David Paddock, U.S. Fish and Wildlife Service, Garrison Dam Fish Hatchery, P.O.Box 530, Riverdale, ND, 58565

Garrison Dam National Fish Hatchery is located in central North Dakota and has beenoperated by the U.S. Fish and Wildlife Service since 1964. Currently the hatchery hasthree buildings used for the production of cold water species and 64, 1 acre (0.6 ha)earthen ponds used for the production of warm and cool water species. The hatcheryincubates about 48 million walleye eggs a year that are collected from wild stocks,primarily from Lake Sakakawea and Devils Lake, North Dakota. Survival to the eye stageaverages 47%, but varies, depending upon the source of the eggs.

Because not all ponds can be stocked at once due to the number of ponds that can befilled or drained at a time, it is necessary to stagger the hatching of the eggs tocoincide with pond filling. Controlling the incubating water temperature allows thehatchery to prolong the incubation of some walleye eggs, allowing a crop of northern pikefingerlings to be raised in a particular pond in May, followed by walleye fingerlings inJune. Prolonging incubation is also used to time hatching until the weather and watertemperatures are favorable and zooplankton production is sufficient to support the walleyefry.

Methods

Before spawning starts, an incubation plan is developed to project how many green eggsare needed, based on the requests made by fishery biologists. This information, along withthe number of ponds that will be used and the date that they will be ready for stocking,determines how the eggs will be divided among the incubators.

Each incubation jar has been calibrated and marked in 0.5 qt (0.47 L) increments toallow for easy inventory. Four qt (3.8 L) of eggs are ladled from the cooler into eachjar, and the water flow is adjusted until the eggs roll uniformly.

Spawning begins in early April. Fertilized eggs are transported from the spawning areasto the hatchery in coolers. The eggs are tempered if there is more than 8F (13.3C)difference between the water temperature in the incubator and the water temperature usedto transport the eggs.

Because the hatchery's water supply comes from Lake Sakakawea, fungus infestationswould be a problem unless kept under control during incubation by treating the eggs withformalin (1,667 ppm for 15 min every other day). Because the lake temperature isapproximately 35F (1.7C) when spawning starts, some of the water is heated by electricboilers to provide warmer water for incubation. Each incubator is supplied with heated andunheated water and the flow of each is controlled to produce the desired watertemperature.

The eggs are hatched in nine incubation units. Each unit contains 28-40 incubationjars. Heated water is degassed by flowing through a packed column and is mixed withunheated water before it enters the upper trough if a cooler temperature is desired. Bymixing the water in this way, the water temperature of each incubator can be different andadjusted to within 0.5F (0.28C) of a desired temperature. Water temperatures are recordeddaily for each lot of eggs and adjusted if necessary. As the hatching date approaches, theeyed eggs are inventoried using the increments on the jars and monitored so that thehatching date can be recorded. Past records have been used to generate a computer programthat determines what temperature the eggs should be incubated to obtain hatching at apredicted date.

When an extended incubation period is desired, the eggs are incubated at a minimum of46F (7.8C) for the first 5 d to allow for initial embryo development. The temperature canbe lowered after this 5 d period until the eggs are close to hatching. A day beforehatching, the temperature is increased to a minimum temperature of 56F (13.3C) so the frywill be active enough to escape their egg shells. This procedure has allowed theincubation period to be extended to 42 d. There has not been a noticeable reduction in thepercent eye up in eggs that were incubated using this procedure, but an increase in frymortality has been observed. It is not yet known if this is due to the low incubationtemperatures or because the water temperatures were not increased before the fry startedto hatch. A comparison of the survival rate of these fry in ponds has not been made withfish whose incubation period has not been prolonged.

When hatching starts, the water flow from the incubator is redirected from the drainline into a "catch tank". The water flow through the incubator directs the fryout of the jars, through the troughs, and into the tank.

The catch tank has a wire screen that is covered with polypropylene filter cloth (1,024openings/inch2) to prevent the fry from escaping. To help keep the screen frombecoming clogged with egg shells and other debris, a in (0.6 cm) perforated rubber hoseis attached to the bottom, upstream side of the screen and connected to an air supply. Theagitation from the air bubbles keeps the screen relatively free of debris. Debris is alsosiphoned from the bottom of the tank periodically using a in (1.9 cm) hose when thetank has relatively few fry.

Fry are concentrated into one area of the tank for harvest. The tank is covered exceptfor a small area which is illuminated by a 150-watt flood light hung about 3 in (7.6 cm)above the water. Fry are attracted to the light and congregate in the immediate area,which keeps them away from the screen and makes their removal easier. Fry are removed fromthe catch tank when they are 1-4 d old. Fry are captured using a dip net made of Dacroncloth. Fry are enumerated using the volumetric displacement method and placed intobuckets. Oxygen is supplied to the buckets by small air stones that are hooked up to anoxygen bottle. Fry are then quickly transported to the ponds and stocked.

 

Arctic Char Culture in WisconsinSponsored by The Wisconsin Department of Agriculture, Trade and Consumer Protection

By: Dave Mueller, Rushing Waters Fisheries Inc., P.O. Box H, Palmyra, WI 53156,800-378-7088

This project is an attempt to diversify aquaculture opportunities for Wisconsin troutgrowers. The main goal of the project is to find an alternative cold water fish speciesthat can be raised in much the same way as trout, yet perform or sell at least as well asour present selection, mainly rainbow trout.

Inquiries into the best candidate species led to the Arctic Char (Salvelinus alpinus).This species is being farmed in increasing numbers across Canada and northern Europe. Itis just now starting to grow in popularity with American producers. The taste of Arcticchar is described to be slightly more flavorful than trout but not as flavorful as salmon.Farmed Arctic char sells at a slightly higher price than farmed rainbows of the same size.Char growth is said to be better than rainbows, especially in very cold water and duringwinter months. A survey of our customers revealed good interest and a willingness to buyWisconsin grown Arctic char.

We do not expect all trout farms (or growers) to be suited for Arctic char production.Each farm has different physical and design characteristics that play a major role whendetermining suitability. Dealing with regulatory agencies can be intimidating. The earlylife stages are unpredictable and the cost of char eggs is much higher than rainbow eggs.Despite the drawbacks, char culture can be an alternative to raising traditional coldwater species.

During the winter of 1994 we initiated the process of getting Arctic Char on ourhatchery license. The main obstacle to clear for this problem was to submit to the WDNR anEnvironmental Assessment. In our case, escapement and the introduction of disease were themost obvious risks. To satisfy the escapement question, we planned to keep the fishsecured at the farm by using screens, bars, and by keeping the fish in upstream raceways.We also pointed out that since our farm discharges into the warm waters of the Rock riverwatershed, any escapees would be unlikely to survive summer temperatures. Disease worrieswere eliminated by agreeing to import eggs certified disease free by the CanadianDepartment of Fisheries and Oceans.

Understandably, the WDNR is not enthusiastic about bringing exotic species into thestate. Nevertheless, they were cooperative and helpful as they realized we were not doingthis on a whim and intended to proceed openly and legally.

By using the "Aquaculture Buyer's Guide", I found a few char egg suppliers(all located in Canada) and phoned them regarding the availability of eggs and discussedwith them char culture techniques. With few exceptions, I found that they were extremelycooperative and talking with them was very easy. I believe all of them said that if Icould raise brook trout, I could assume Arctic char would be no different. This made sensesince they are close relatives.

The price and terms of the eggs' sale varied widely and all required a deposit,sometimes months in advance, to reserve eggs. No supplier could guarantee he would haveeggs available for sale. They all complained about the fickle nature of their Arctic charbroodstock. Some told me that the females do not spawn every year and unpredictableweather disturbs the process. Prices vary from $80 to $190 (Canadian dollars) per thousandeggs.

After getting the char put on our license and finding a supplier who met our criteria,the Importation Phase had begun. We arranged for a delivery in late February 1995. Ilearned too late that there is such a thing as a customs broker who would have streamlinedthe process. All agencies were helpful and cooperative. US Customs and US Fish andWildlife Service went the extra mile for us as complications arose when the eggs arrivedat the airport.

The eyed eggs were about the same size or slightly smaller than typical rainbow eggs.The Von Bayer count was 63 (4.8mm). We incubated the eggs in a Heath hatching cabinet.Water chillers kept temperatures at 43 F, which the Canadians said was best. The chargrowers told me that it is important to incubate the eggs in water no warmer than 45 F andpreferably 43 F. Therefore, we had to plan a chilling system for our 50 F water supply.Later on in the project we found the chilling system to be unnecessary.

The performance of our eggs was very disappointing. Upon arrival, viability was about81%. Hatching started in 5 days and proceeded for an agonizing 15 more. We picked 5,820morts (out of 19,600 shipped) during the hatch. The supplier acknowledged he was havingthe same problem with the eggs he kept and he reimbursed us for the high mortality.Parental health and/or genetics was brought into question as we started to notice hundredsof two-headed sac fry along with many other deformities.

We began to introduce starter mash when the yolk sacs were about half absorbed. Thechar did not swim up the same way the rainbows do. They progressed from sluggish sac fryto first- feeders that are bottom oriented for a few weeks. We verified feeding bychecking backlighted samples for full guts. Mortality remained high as the deformed sacfry used up the last of their reserves and died. We raised temperatures to 50F (ambient),after swim up. Feeding and growth then resembled rainbows. By that point mortality waswell over 50%. Gradually mortality diminished and the remaining fish grew very well. Theyfed eagerly from both belt feeders and thrown feed.

After 180 days the char's growth surpassed our rainbow's rate. Keep in mind the charwere less crowded than our high production rainbows and we may have tended to give thechar better care because of the novelty of the project.

The char were stocked into a raceway pond after 9 months. Total number stocked was5,500 fish. They immediately started to use the demand feeder and took thrown feed.

The pond performance of the char was excellent. Their growth was good and mortality wasnegligible. The char tended to distribute themselves more or less evenly throughout theraceway. No tight schooling as the rainbows do. They were more sensitive to nearbymovement but still took thrown feed.

The char took moving and grading very well with one exception. While transferring thechar into a raceway about a dozen were dropped onto dry grass, which is common whenhandling many netfulls of fish. As we do with rainbows, the dropped char were flipped intothe raceway. Those fish quickly developed skin infections. Some recovered, some did not.We concluded the char have a much more sensitive slime layer than rainbows. Except forthose mortalities, death from moving episodes were non-existent.

Grading char for market is almost a pleasure when compared to rainbows. We use an openbottom grading box with bars spaced at 1 inch intervals. Lifting the box out of the waterto "shake out" the smaller fish usually results in workers being covered with acombination of water, fish, slime and feces. Not so with the char, which squirm in the boxin a snake-like manner , splashing very little. As with rainbows, mortality is very lowand usually the result of being stepped on by workers or trapped under the seine net.

We found the char took much longer than rainbows to deposit pigment in their flesh. Ittook the char almost 4 months on feed laced with pigment (canthaxanthin) to start turningred. The males tended to deposit pigment in their skin, turning their lower flanks abright orange-red. The females retained their purple-violet color and the flesh tookpigment faster than the males.

At 15 months the largest char in the raceway were 13 inches long which yielded a 10-12oz. product (head on, boned). Our restaurant customers were eager to put char on the menubut after an initial flurry, sales dropped off sharply. Customers reported slow sales dueto trout-like appearance and taste, but at a much higher price. Others cited therelatively unknown status of the arctic char to the general public.

Our '96 group of Arctic char started much better than the '95 group. The '96s were froma supplier in British Columbia who was a far better source. Viability upon arrival was98%. This group was split and incubated at 50F and 43 F. As the hatch started andprogressed, it became apparent that the 50 F eggs were hatching quickly and with fewermorts than their colder counterparts. We decided to disconnect the chillers after itbecame apparent incubation at 50 F was resulting in less mortality and a quick hatch (thishatch took 7 days - mortality was 7%).

This group progressed into swim-up stage without problems. Shortly after though, westarted noticing there were many emaciated fish and they started dying off. We did nothave a problem at this stage with the previous group. We were giving this group ZeiglerSalmon starter mash while the previous group received Biodiet. There were no flared gillsor lethargic behavior indicating problems other than starvation. Feed was always availableto the fish. Mortality stayed high for several weeks and subsided after we lost about 60%.

The survivors performed well as the previous group did. We are expecting harvest tostart at 15 to 16 months (1 lb. fish).

A third group has been started this year. They are now at swim-up and are showing nosigns of feeding problems (they are being fed Biodiet). Mortality to date is probably lessthan 5%.

As previously stated, customers who initially showed much interest in the product werereluctant to reorder. Reports came back saying the char tasted too much like trout tojustify a higher price. They also said arctic char is not well known to the generalpublic. We have since realized some errors in our marketing strategy.

With great demand for the first char sales, we priced the fish higher than we shouldhave. Later, lowering prices brought in a few customers, but many were probably lost forgood. Low initial prices would have most likely resulted in more return business and giventhe char greater exposure.

Recently, two Chicago-area seafood distributors started buying our char in amountssufficient to sell us out of our production in three months. Char prices to wholesalersare lower than they would be to restaurants, however they remain higher than our price forrainbows of the same size. It is to be hoped that demand will increase as a result ofthese sales.

There are plans to increase demand for Wisconsin raised arctic char through variouspromotional venues, such as trade shows and advertisements. We have also startedconducting a feed trial to see if taste and pigmentation problems can be solved with highfat feeds.

Please feel free to contact me if you have questions regarding Arctic char or thisproject.


The RightEquipment And Technology to Raise Fish For The Future

By: Richard Johnson, AQUAFARMS 2000, INC., 8896 Lake Jane Trail, Lake Elmo, MN 55042,800-293-2963, E-Mail: richardej@worldnet.att.net

There was a new face at the exhibitor booth during the recent Wisconsin AquacultureConference in Stevens Point, Wisconsin, March 14 & 15. Dick Johnson of Aquafarms 2000,Inc. braved the snowstorm opening day to set up a display of the products they have tooffer to the fish rearing industry. The company may have been a first time exhibitor atthe Wisconsin Conference, but they have been around 22 years making fine fiberglass fishtanks. They have supplied tanks and other equipment to U.S. Fish and Wildlife Servicefacilities all over the country, as well as many State DNR's, and private aquaculturefacilities. Their motto is to supply the right equipment and technology to raise fish inthe next century or should they say the next millennium?

The U.S. office of Aquafarms 2000, Inc. is in Lake Elmo, Minnesota. The company wasstarted in Ontario, Canada by aquaculture pioneer Alex Plomp in 1975. The tank buildingoperation was started along with a successful aquaculture project that supplied highquality trout to the "white table cloth" restaurants in Toronto. Alex's daughteris continuing the fish farm operation today. With Alex's knowledge of fish rearing, heknew what equipment the industry needed to raise healthy fish, and he set out to supplyhatcheries all over North America.

The main high quality characteristics of tanks manufactured by Aquafarms 2000 are:

  • Light weight, sturdy tanks constructed by hand-layup for increased strength and durability. The tanks have alternate layers of 1 oz. mat and 18 oz. woven roving.
  • No glass "chop spray" techniques are allowed. Spray layup is cheaper but produces a weaker sidewall.
  • Smooth Gelcoat interior finish for easy maintenance, better sanitation, and high production per unit.
  • Unobstructed open area for the rearing of fish.
  • Telescopic exterior standpipe for the adjustment of water levels.
  • High water capacity.
  • Special design for easier shipment. Most larger orders are delivered by Aquafarms trucks.
  • And most important, competitive pricing.

The company also supplies hatching troughs, biofilters, mechanical filters, fishfeeders for all applications, pumps and instrumentation. Alex and Dick will also provideengineering services to design a successful hatchery or fish rearing facilities, whetherit's a small hatchery or a high tech high water reuse fish farm.

 

Hatchery Tip

Watertight Sealant: The Adhesive/Sealant Fast Cure 4200 from 3M Marine is a one-part,all purpose marine polyurethane formulation that chemically reacts with moisture. Itdelivers a flexible bond with good adhesive to all water surfaces including wood,fiberglass, gelcoat, plastics and metals. It is well suited for sanding or painting. 4200also forms a watertight, weather resistant seat on joints and hardware above or below thewater line. Available in white or black, Fast Cure 4200 becomes tack-free in I to 2 hours,then fully cures in 24 hours.

Rust Converter: All ferrous metals will rust when left unprotected from moisture andoxygen and the presence of salts and acids just speeds up the process. Once corrosion hasbegun, the most common method of combating it has been to sand, scrape or blast down tobare metal, then add a primer coat, over coat and perhaps even reseal. Neutra Rust 661however, is a quick and economical way to eliminate rust. It is applied directly to therusted surface where it immediately converts rust, and any water and oxygen, into animpermeable coating, which will serve as an excellent primer for most standard orsynthetic coatings.

NeutraRust is non-toxic, biodegradable, non-flammable, has very low VOC's and containsno lead or phosphoric acid.

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.

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Last updated: November 19, 2008