Location: Warmwater Aquaculture Research Unit2013 Annual Report
1a. Objectives (from AD-416):
Develop feeds and feeding practices for optimal nutrition, increased production, and improved water quality of pond-raised catfish; Increase the reliability, efficiency, and cost-effectiveness of catfish fry production through the use of new and improved technologies; Apply engineering approaches to design new or modified live aquatic animal harvesting equipment; Increase the reliability, efficiency, and cost-effectiveness of catfish production through the use of new and improved culture system technologies.
1b. Approach (from AD-416):
All research conducted under this agreement addresses components of the USDA-ARS action plan for National Program 106-Aquaculture. Practical, production-related problems facing the farm-raised catfish industry in the southeastern United States will be addressed through a multidisciplinary approach focused on improving the efficiency of traditional cultural practices and developing new technologies to address inefficiencies associated with traditional pond culture technologies. Research projects will be conducted in the field using pond research facilities at the National Warmwater Aquaculture Center, Stoneville, Mississippi. Research will address the following broad subject areas: fish nutrition and feeding, nursery pond management, harvesting technologies, development of alternative culture systems, and managing the environmental impacts of pond aquaculture.
3. Progress Report:
This project addresses key production inefficiencies over a range of issues, including nutrition, production systems and product quality. During Fiscal Year 2013, a pond study was conducted to examine the use of hydrolyzed feather meal as a replacement for soybean meal in diets for pond-raised channel catfish. Four 28%-protein diets were evaluated that contained 0, 5, 10, or 15% hydrolyzed feather meal. No significant differences were observed for weight gain, feed conversion ratio, and survival among fish fed various levels of hydrolyzed feather meal. There were also no significant differences in net yield of fish fed diets containing 0, 5, and 10% hydrolyzed feather meal, but net yield of fish fed a diet containing 15% hydrolyzed feather meal was significantly lower than that of fish fed the control diet. Fish on diets containing 5% hydrolyzed feather meal and above were fed significantly less feed than fish fed the control diet. Results showed that with supplemental lysine hydrolyzed feather meal may be used at 5% of the diet without marked impact on performance of pond-raised catfish. However, fish fed diets containing hydrolyzed feather meal at 5% and above had reduced carcass and fillet yield. Studies on stocking different ages of fry have been completed. Stocking hatchery-fed fry resulted in 41.6% survival, stocking swim-up fry resulted in 7.1% survival, and stocking sac fry resulted in 4.5% survival. The final recommendation is to continue feeding fry in the hatchery before stocking to improve survival rates. Following stocking in nursery ponds, fry were shown to thrive without commercially processed feed for 6 weeks by feeding on naturally occurring zooplankton. This work showed that implementing a regimented fertilization program to optimize zooplankton levels can provide a sufficient source of food for fry during the first 4-6 weeks of fingerling production.Reducing or eliminating fry feedings during the initial stages of fingerling production can reduce feed costs by at least $236/acre. Adding threadfin shad to catfish ponds did not improve catfish growth but reduced algae-caused off-flavor in summer and caused fishy flavors in the winter. Presence of fathead minnows had no effect. In a second forage fish study, no differences were detected among treatments. Lack of forage fish effect was attributed to wild-spawning of catfish, confounding treatment effects. Hybrid catfish stocked at 37,000 fish/hectare (ha) in a 1.8-ha split pond grew to an average size of 0.73 kg in 210 days, for a gross yield of 23,600 kg/ha. Although total production was high, average fish size showed a density-dependant reduction compared to fish stocked at lower rates. The recommended stocking density is 24,700 fish/ha for fastest fish growth.