Location: Warmwater Aquaculture Research Unit2010 Annual Report
1a. Objectives (from AD-416)
The overall objective of this project is to improve the profitability of channel catfish by improving farm-level production efficiency. This will be accomplished by addressing key production inefficiencies over a broad range of issues (nutrition, production system design, and product quality) affecting production in all post-hatchery production phases (fingerling production, foodfish production, and post-harvest). Over the next 5 years, we will accomplish the following objectives: Objective 1: Explore alternative feed ingredients to reduce production costs of catfish. Objective 2: Improve culture methods for fry and fingerling production. Objective 3: Develop new and improve existing production strategies for large catfish. Objective 4: Determine the relationship between pre-harvest, harvest, and post-harvest practices and product quality.
1b. Approach (from AD-416)
Catfish aquaculture was a profitable and rapidly growing industry in the southeastern United States prior to 2003. Since that time, profitability has declined due primarily to competition from imports and increased feed prices. Although these macroeconomic issues are difficult to address, new technologies can improve farm production efficiency and help restore profitability. This project addresses key production inefficiencies in fish nutrition, production system design, and product quality. Objective 1 will address the rising cost of catfish feed by finding suitable replacements for traditional feed ingredients that have recently increased dramatically in price. Objective 2 will evaluate the use of natural feeds and different stocking densities on growth and survival of catfish fry, with the goal of reducing feed costs and improving growth of fish from fry to fingerling stage. Objective 3 will evaluate ways to reduce feed-input costs by providing food-sized catfish with forage fish as a secondary source of food. A second subobjective proposes to alter pond design to overcome production limitations related to loading limitations of traditional earthen ponds. Objective 4 will address the large number of fish rejected for processing due to product-quality issues. Fish rejected for processing has become an important inefficiency for foodfish producers. The benefits of this project will be development of techniques to enhance economic performance, improve global competitiveness, and allow domestic aquaculture to reduce dependence on imports to meet the U.S. demand for seafood.
3. Progress Report
Nutrition and Feeding: 1) A catfish fecal collecting system consisting seven 3–gallon digestibility tanks have been built. Preliminary tests show the digestibility coefficients for protein and dry matter were comparable to results previously reported for practical catfish diets. A digestibility trial was initiated in June 2010 to determine apparent nutrient and energy digestibility coefficients for several alternative protein sources including corn gluten feed, distillers dried grains with soluble, canola meal, poultry by-product meal, and hydrolyzed feather meal. Fish are currently being fed and fecal samples being collected. 2) A pond study was initiated in March 2010 to evaluate the use of corn gluten feed and cottonseed meal to partially replace soybean meal and corn in catfish feeds. The study tests five isonitrogenous (28% protein) diets with corn gluten feed and cottonseed meal (approximately 1:1 ratio) replacing 0, 25, 50, 75, and 100% soybean meal in the diet. Fish are currently being fed the experimental diets. Data to be collected include the total amount of feed fed, weight gain, survival, feed conversion ratio, carcass and fillet yields, and fillet proximate nutrient composition. Improved Culture Methods: Fry of different ages have been stocked into research ponds and are in the process of being cultured through the growing season. New Production Strategies for Large Catfish: 2) To test the effects of co-culturing catfish with forage fish, thirty ponds have been stocked with catfish stockers at 6,000/acre. Three forage-fish treatments (10 ponds each) were assigned to receive stocking of threadfin shad, fathead minnows, or no forage fish. The fish are currently being cultured through the growing season. 2) An existing 5-acre pond has been divided into a 1-acre fish-holding basin and a 3.5-acre waste-treatment basin. The two basins have been connected with two sluiceways: one sluiceway has a 12-foot-wide, 8-feet-diameter paddlewheel that recirculates approximately 15,000 gallon of water per minute between the basins when operated at 2.5 rpm. An automated oxygen monitoring system has been installed that initiates either circulation or aeration depending on dissolved oxygen conditions. Hybrid channel catfish (45,000 fish of approximately 0.1 pounds apiece) have been stocked into the fish basin and have been fed for approximately 3 months. Fish will be harvested in October, 2010.
5. Significant Activities that Support Special Target Populations
Production inefficiencies related to feeding practices, nursery pond management, and harvesting in commercial catfish culture reduce profits and more efficient practices will benefit operators of small farms. The USDA Census of Aquaculture conducted in 2000 classified 84% of catfish farms as small businesses, with annual sales of less than $500,000. Of the 1,370 catfish farms in the United States, 38% (515) reported annual revenues of less than $25,000. Production inefficiencies disproportionately affect small farms because they are more susceptible to economic impacts related to interruption of cash flows.