Aquaculture Virginia 2006

Non-Technical Summary: In terms of market opportunity, yellow perch has been identified as an attractive species for aquacultural production. However, the aquaculture potential of this species is dependent upon the development of domesticated stocks of yellow perch, and a better understanding of the economics of producing this species in recirculating aquaculture systems. The purpose of this project is to improve technology needed for closing the life cycle of yellow perch, a necessary requirement for domestication of the species. The project will also improve our understanding of the economics of production of yellow perch in recirculating systems, which will help project planners optimize the design and scale of yellow perch production systems. <P> Approach: We will examine the effect of annual photothermal regimes during the broodstock rearing period on spawning success of yellow perch. Broodstock will be divided into two treatment groups. Treatment Group 1 will experience annual photothermal regimes similar to those experienced by wild fish in eastern Virginia for each of the two years before spawning. Treatment Group 2 will experience constant daylength (12 hrs) and temperature (22 deg. C) up until 5 months before spawning. For the last 5 months before spawning Group 2 will experience the same photothermal regime as Group 1. Half of the fish from each treatment group will be induced to spawn with injections of LH-RHa, while the other half will be left to spawn naturally. Data will be recorded for each treatment group on the number of spawns, average number of eggs per spawn, fertilization rate and hatch rate. A computer production model will be used to examine the economic viability of yellow perch production in recirculating aquaculture systems. The model will be based on a modular, scaleable system design and will utilize production and cost data gathered on existing systems. We will examine how scale of investment affects profitability. The model will use pro forma cash flow analyses, income statements and balance sheets to calculate a variety of measures of economic profitability, including initial capital investment requirements, NPV, IRR, breakeven costs, breakeven production levels, and investment payback periods. Sensitivity analyses will be performed to determine the sensitivity of profitability to changes in key variables. The feasibility of producing vegetables utilizing waste effluent from intensive fish culture will be investigated by installing a fiberglass raceway (8,000L) containing 1500 koi in a greenhouse. A crop of bibb lettuce (Lactuca sativa L.) will be grown aquaponically over the raceway. Two separate systems utilizing different aquaponics techniques have been designed and are being constructed for this research. The first system will use 4 in round PVC pipe, which has been filled with rockwool for the growing media and will be installed over the raceway. The second system consists of an A-frame structure mounted over the raceway where plants will be transplanted to net baskets fixed to a flat sheet of PVC. A misting system will mist the roots and growing media with aquaculture waste water. These two systems will allow a comparison study of the growth of plants using two distinctly different aquaponics methods. To identify food safety issues associated with use of fish effluent to produce vegetables, aquaponically-produced lettuce will be tested for total microbial populations and selected human pathogens. Microbial analyses will include Total Plate Count, Fecal Coliforms, Total Vibrio, Listeria, Salmonella, and Mycobacterium. If the fecal coliform counts are greater than 14/100 ml MPN, an assay for Escherichia coli 0157:H7 will be performed. If the analysis for Total Vibrio organisms is positive, specific tests will be performed for both Vibrio parahaemolyticus and Vibrio vulnificus.