Fish Stories
Vol. 2 No. 1 March 17, 1995

Alabama Cooperative Extension Service
Department of Fisheries and Allied Aquacultures
Auburn University, Alabama

SLOW-RELEASE FERTILIZER UPDATE---Last year we reported on research underway at Auburn University to develop a slow-release pond fertilizer. Since the nutrients would be released slowly into the pond over the course of the year, the number of applications and the amount of fertilizer required to create and maintain an algae bloom would be dramatically reduced. We are pleased to report that the time-release fertilizer is now here!
      It comes in a small, pre-measured tray sufficient to fertilize a 1/2 acre pond for one year. Each tray contains five small bags of fertilizer. The first four bags have a formulation of 12-49-6 and are broadcast into the pond from the shore. The fifth bag is a time release fertilizer (10-47-0) and is poured onto the tray which is staked down in 18 to 24 inches of water.
      That's all the fertilizing the pond will need for the year! Each tray is priced at $49.90 and is available from the Alabama Farmers CO-OP Crop Stores. Approximate annual cost would $100/acre. There are 48 trays to a pallet.
     Remember, DO NOT FERTILIZE IF WEEDS ARE PRESENT and DO NOT FERTILIZE IF THE TOTAL ALKALINITY IS BELOW 20 ppm. Ponds low in alkalinity need to be limed. County agents, specialists and others can check approximate lime requirements from an alkalinity test of the water. The Soil Testing Laboratory can check the soils.
     For more information contact our office at (334) 844-3594, the
Alabama Farmers Coop. at (205) 353-6843 or the Alabama Farmers
Coop. in your area.

FIRE ANTS---Fire ants can be a problem around the pond to anyone who might get bit. They frequently build their nests next to posts and have been known to short-out aerator breakers and switches. There are several pesticides on the market which can be very effective in controlling fire ant colonies if used properly and have been suggested for use on top of dams and around electrical -poles or outlets.
     The following is a run down of three fire ant insecticides: Amdro, Logic, and Award. In each case the chemical bait is spread around the nest were it can be collected by the ant workers and distributed throughout the nest. In a few weeks it will kill the entire nest including the queen although follow-up applications may be required. The insecticides function as slow acting, hormonal baits and their toxicity to humans and fish is minimal. Mid- to late-day applications are the most effective as this is when the ants are actively foraging. Always follow the directions on the label for best results.

Amdro
     Amdro Fire Ant Insecticide is produced by American Cyanamid Company / Wayne, NJ 07470. They can be reached at 1-800-652-6013 for general information or at (201) 357-3100 in case of an emergency. Although it is "practically nontoxic by ingestion in single doses" (material safety data sheet, no. 2075-06), no antidote exists if overdose should occur. This product may be toxic to fish and should not be used where run-off could get into the water or near food crops or other animals intended for human consumption. Amdro is in the hydramethylnon chemical family and disrupts the ants' utilization of energy. It takes 2 to 4 weeks to kill colonies treated with hydramethylnon.

Logic
     Logic Insect Growth Regulator Bait Formulation is a product of Ciba-Geigy Corp./ 410 Swing Road / Greensboro, NC 27409. They can be reached at 1-800-334-9481. It is used to control fire ants and big-headed ants. Contamination from drift, run-off or improperly disposed wash water may be sufficient to kill aquatic invertebrates although a substantial amount is required to kill fish. It is unlawful to use near pasture or rangeland grazed by domestic animals. Logic is approved for use on horse farms (if horses are not used for human consumption) and certain non-bearing crops. It belongs to the fenoxycarb chemical family and disrupts the queens reproductivity. Although it takes up to 6 to 8 weeks to kill the colony the percentage killed is high.

Award
     Award is also produced by Ciba-Geigy Corp. It has the same formulation as Logic, the difference is that Award has been approved for use on turf and ornamentals while Logic is approved for use on horse farms and non-bearing crops.

Non-Chemical Control
     A non-chemical remedy is to pour boiling water on the mound, however, this may only be effective in causing the colony to relocate. Mixing the contents of two mounds or other forms of mound disturbance may also cause the relocation of the colony.

     For more information on fire ants and other treatments, refer to Extension Circular ANR-175, "Imported Fire Ants In Lawns, Turf, And Structures" available from the Alabama Cooperative Extension Service, Auburn University, Alabama 36849-5612.

SEAFOOD GAINING POPULARITY IN RESTAURANTS---A detailed menu analysis by the National Restaurant Association has revealed that the percentage of menu's carrying seafood items and the variety of seafood dishes have both been increasing for the past five years. Shrimp appetizers are the most popular items appearing on 75% of menus, up from 64% in 1988. The popularity of crab and squid have also been rising. Owing to decreased demand for raw dishes, oyster and clam appetizers were found on fewer menus.
     Although the number of offered soups has dropped, shellfish varieties appear on 39% of menus, "far out pacing the venerable chicken." Clam chowder is the single most popular soup offered.
     Although finfish soups have been slipping in popularity, finfish takes center stage as entrees, appearing on 90% of menus, with most menus offering three or four choices (up from one or two in 1988). Salmon remains the most popular, showing up on half of all menus. Red snapper, swordfish, tuna, halibut, catfish and other varieties are also on the rise. Shellfish are also popular entree items appearing on 80% of menus with shrimp as the best seller. Shrimp's popularity is due to its variety and year-round availability. It is also helped by restaurants successfully marketing shrimp dishes, such as popcorn shrimp, to children.
     Seafood-based salads, most notably tuna and shrimp, have also been gaining ground and are found on 27% of menus, up from 20% five years ago. Crab, squid and lobster salads are also popular.

SOURCE: Frozen Food Age, March 1995

CUSTOMERS, CONCERNS AND COMPLAINTS---Positive customer perception is difficult to gain and easy to lose. Seafood retail customers recently listed their major concerns and what they considered to be the greatest obstacles to increased sales.

	CONCERNS		OBSTACLES
1.	Quality	1.	Inconsistent Quality
2.	Price/How to Cook	2.	Consumer Education
3.	Taste	3.	Poorly Trained Counter Personnel
4.	Safety	4.	High Prices/Safety Concerns
5.	How to Store	5.	Consistent Availability

SOURCE: Maryland Aquafarmer, Summer 1994

USING BENTONITE TO SEAL LEAKING PONDS---Nothing is more frustrating to landowners than to find that their recently constructed pond leaks like a sieve. No matter how much planning and care is taken in building a pond there are no guarantees that it will hold water. Leaky ponds can sometimes be repaired but remedies are almost always costly.
     If you have a new pond that leaks, sometimes just simple settling of the soil in the dam over time may cure the problem. In many cases another core constructed to cut off seepage channels beneath the dam can be engineered to seal off the leak. Leaks along drain pipes can also be identified and repaired. Exposed sand and gravel seams in the pond bottom are common sources of leaks. Sometimes these areas can be found and covered with a layer of good quality clay.
     Bentonite clay is often recommended to help seal porous pond bottom soils. When wet, bentonite swells 12 to 15 times its original size, effectively sealing off the spaces between soil particles. We recommend that you work with your Soil Conservation Service, District Conservationist or qualified engineer to determine the problem and the likelihood that bentonite or any other remedy will seal the leak.
     Bentonite can be the solution to a leaky pond but it is almost always expensive and it doesn't work under all circumstances. The following is a review of bentonite and its use for sealing ponds.
     First off, don't confuse locally mined bentonite, called calcium bentonite, with the swelling type sodium bentonite from Wyoming. The local, Alabama bentonite lacks the swelling capacity of Wyoming bentonite and causes rapid changes in pH which can lead to fish kills following its use.
     Western swelling type sodium bentonite is sold under various trade names. It can be obtained in limited quantities from several local dealers. The price is about $7.50 per 100-pound bag. At a minimum application rate of one pound per square foot, a 100-pound bag would be applied to 100 square feet of pond soil. Therefore, about 20 tons, or 400 bags, would be needed to cover an acre of pond bottom. Bentonite may also be purchased in bulk directly from Wyoming at a cost of approximately $147 per ton ($67 per ton of product plus $80 per ton shipping). Either way, this works out to a minimum cost of about $3,000 per acre. Because of its high cost, bentonite use may be limited to patching leaky spots in ponds and not for lining an entire pond.
     There are three general methods for applying bentonite to ponds. They are the blanket method, the mixing method, and the sprinkle method. When the blanket method is used, the top 4 to 6 inches of the dry pond bottom needs to be removed. The freshly exposed surface is then smoothed and covered with a layer of bentonite. The bentonite layer is then covered with the previously removed soil and the whole thing is compacted by rolling or tamping. If possible, water flow into the pond should be controlled to prevent damage to the treated surface before the pond fills. It will take several days for the bentonite to become saturated and form an impermeable barrier to water seepage.
     When the mixing method is used, the bentonite is mixed with the soil. The pond bottom must be cleared of all rocks and vegetation before bentonite can be applied to the surface. The bentonite is spread evenly, and then tilled or disked 4 to 6 inches into the soil. The soil is then compacted by rolling or tamping. No topcoat of soil is required with the mixing method.
     Bentonite can be sprinkled on the water surface over a suspected leak. Although this is the least effective of the three methods, it eliminates the need to drain the pond.
     Application rates range from 1 to 8 pounds bentonite per square foot. The application rate is determined by the seepage rate.
     To best determine the minimum amount of bentonite required to prevent or reduce water seepage to an acceptable rate, perforate the bottom of a bucket and place 1 to 2 inches of gravel in the bottom. Cover the gravel with 6 to 8 inches of the pond soil you will be treating. Tamp down the soil, add water and observe to determine the seepage rate in your pond. Once you have determined the seepage rate you can test for the effectiveness of the three possible methods of bentonite application.
     If the blanket method is to be used, remove the top 3 to 6 inches of soil from the container, add 1/2 pound bentonite per square foot to the freshly exposed surface and then replace the soil that was removed. Tamp it down, add water and observe the results. If the mixing method is to be used, mix the top 3 to 4 inches of soil in the bucket with 1/2 pound bentonite per square foot. Tamp it down, add water and observe the results. If the sprinkle method is to be used, prepare the container with gravel, soil and water as before, then sprinkle the bentonite on the water surface and observe the results.
     Repeat the method you have chosen using progressively more bentonite until an acceptable minimum amount is reached that appears to control seepage. Finally, add 25 to 50 percent more bentonite to the actual pond soils than shown by the tests to allow for the greater water depth of the pond and the inefficiency of large-scale applications.
     Bentonite may be purchased in a coarse granular form or fine powder form. The cost per pound is the same for either form. The granular form is more effective when sprinkled on the water surface than the powdered form because the larger particles are able to sink quickly to the bottom before they are saturated with water and swell. Because the powder can create a lot of dust when it is spread out or disked into dry soil, the granular form may be easier to use than the powdered form when applied in this manner. However, the powdered may be more effective because it does a better job of filling in the spaces between soil particles and sealing leaks. Bentonite is only about 40% as effective at sealing leaks when it is applied to wet soils as when it is applied to dry soils.
     Patching leaks is almost always expensive and not always effective. Therefore, preventing leaks initially with properly designed and constructed ponds is essential. If a leak does develop, check with your Soil Conservation Service to determine if bentonite is an option.

This concludes another edition of online Fish Stories. Please direct questions and comments to:
Brandon Foster
(bfoster@acenet.auburn.edu)
202 Swingle Hall