Effect of Stocking Density on Growth, Yield, and Costs of Producing Rainbow Trout, Oncorhvnchus mykiss, in Cages

摘要

Rainbow trout, oncorhynchus mykiss, were raised in culture cages (1 m~3) to determine the effect of stocking density on growth, survival, and percentage of market-size fish. Large fingerling rainbow trout (20-25 cm. 232 g average weight) were stockedinto six cages located in a 0.4-ha pond. Two stocking densities (100 or 200 fish/cage) were used, and fish were grown for 140 days (November 2000-April 2001). Average total harvest weight (35.0 kg) in the low-density cages was approximately one-half theaverage total harvest weight (61.2 kg) in the high-density cages. Average weight gain (11.7 kg to 15.1 kg) and feed conversion (1.2 to 1.5) were also smaller for the low-density cages. Average survival was 96.7% for the low-density cages and 94.2% for the high-density cages, with the percentage of market-size fish (> 29 cm) averaging 50.3% and 52.0%, respectively. Production costs for the actual experiment and the revenues from fish sold at the end of the study were collected. An enterprise budget basedon the experimental results for the two densities was developed to determine if a culture operation of this size would produce a net return. Production costs and revenues from (he experiment resulted in a large negative return (-3,124 dollar) and high breakeven price (13.53 dollar/kg).