Grass Carp Production in LVHD Cages with A Soy-Based Feed: Guangxi Province
A feeding trail was conducted in Li Yu Tang Reservoir in Guangxi Province to evaluate production of grass carp in LVHD cages with a soy-based, all-plant protein feed formulated by the American Soybean Association. Grass carp were stocked in three, 4.0-m3 cages at a density of 100 fish per m3. Grass carp grew from 198 g to an average weight of 700 g per fish in 109 days of feeding. Gross production averaged 66.8 kg/m3. Average survival rate for grass carp was 95.3%. Average FCR was 1.83:1. Grass carp growth was erratic in the 4-m3 LVHD cages. This erratic growth resulted from frequent halting of feeding in response to a combination of storm conditions and local electro-fishing operations that were conducted immediately adjacent to the cages by local fishermen. The grass carp were fed only 109 of 139 days during the culture period. Despite the variable feeding response, grass carp were 17% larger at harvest than the 600-g target size. The average fish biomass of 67.8 kg/m3 at harvest was nearly 40% higher than with traditional practices. Results from the trial indicate potential for LVHD cage culture of grass carp, but a follow-on evaluation is needed to fully assess the feasibility of the LVHD technology for culturing grass carp in cages with the ASA soy-based diet.