<OL> <LI> To improve crawfish production through investigation of factors affecting reproduction and through development of early- and out-of-season production strategies. <LI>To develop technologies for the intensive production of coppernose bluegill and for the propagation of two species of marine baitfish. <LI> To refine technologies to facilitate use of high-throughput cryopreservation for selective breeding and hybridization of catfish. <LI>To develop extraction and purification methods for the recovery of oil from alligator fat and to charaterize its physical and chemical properties. <LI> To produce edible films from catfish skin hydrolysates and evaluate uses of these coatings with frozen shrimp. <LI>To determine the molecular epidemiology of Vibrio vulnificus strains isolated from Louisiana raw oysters.
NON-TECHNICAL SUMMARY: Louisiana supports one of the most diverse aquaculture industries in the nation. Numerous challenges require development of new technologies to ensure that the state's aquaculture industries remain viable and profitable. Crawfish production, the leading aquacultural enterprise, depends on natural reproduction and recruitment and the factors affecting the success of these biological processes must be better understood to allow for proper management. Also, the ability to produce crawfish earlier in the season would greatly enhance economic returns. Opportunities exist to stimulate the growth and viability of a marine baitfish industry. The greatest impediment to success is the need to demonstrate that culture techniques are economically feasible. The catfish industry is in decline and different species need to be investigated as possible alternatives for pond culture of food fish. The coppernose bluebill is one such species. In addition, development of technologies to facilitate genetic improvement through selection and hybridization might serve to re-invigorate the catfish industry. Also, value-added uses for catfish wastes could offer alternative income sources as well as improved health and food safety. Louisiana leads the nation in alligator production and oil fat from trimmed from alligator meat during processing is a good source of omega-3 fatty acids and relatively low in cholesterol. Methods to extract and purify this oil are needed. Finally, oysters are very important to Louisiana's economy and epidemiological data is largely lacking on the percentage of environmental Vibrio vulnificus that are virulent.
APPROACH: This proposal contains nine component projects, each with the goal of enhancing the Louisiana aquaculture industry through improvements in existing enterprises as well as investigating the possibilities of creating new ones. These nine projects vary in scope and will generally address enhancements in the production efficiencies of several aquaculture species, the food safety of aquacultural products, and the development of new uses for aquacultural by-products. Crawfish farming, depends on natural recruitment of broodstock to generate each years new crop, which results in highly variable and unpredictable crops. Research will investigate key aspects of crawfish reproduction and recruitment related to crawfish aquaculture production. In addition, crawfish producers need management guidelines and alternatives to increase production efficiency and profitability. Research will also evaluate management strategies to produce early-and out-of-season crawfish and determine movement patterns to traps and subsequent capture efficiency, as influenced by bait type and water temperature. A third project will continue development of methods for the intensive production of coppernose bluegill as a food fish in Louisiana. Feeding trials with a number of fish species indicate that daily feeding may not be required to optimize production yield and feed cost. These concepts will be applied to develop feeding strategies that optimize fish yield and production cost. The development of an aquaculture industry centered on the culture of marine baitfish represents a potential new economic market within Louisiana. Research on economic potential coupled with the feasibility of culture techniques is needed. These areas will be addressed for Atlantic croaker and the fat sleeper in two component projects. A sixth project will expand research to improve spawning efficiency and utilization of genetic resources for catfish aquaculture via high-throughput (commercial-scale) application of cryopreservation. Vibrio vulnificus is a naturally occurring estuarine pathogen frequently transmitted via raw oysters. A collection of 370 V. vulnificus strains previously recovered from Louisiana Gulf and retail raw oysters will be used to study whether V. vulnificus strains isolated from Louisiana raw oysters are predominately virulent type or non-virulent. Louisiana has the highest alligator population in the U.S., and numbers of farm-raised alligators are increasing. Alligator fat is a good source of omega 3 fatty acids and is relatively low in cholesterol. Therefore, efficient extraction and purification processes are needed and will be explored in this component project. Finally, catfish skin is an underutilized resource that can be used as a unique protein source to make fish skin hydrolysates. Its natural antioxidant and film-forming properties make it ideal for coating and edible film material to suppress lipid oxidation of food products. This project will evaluate uses of films and coatings made from catfish skin hydrolysates with frozen shrimp over time for moisture retention, changes in texture, and quality attributes.