水産養殖研究開発ジャーナル

概要

The Effect of Packing on Water Quality Parameters, Survival and NNV Load of Epinephelus coioides Fry after Simulated Transport

Cheng AC, Lee CF, Chen YY and Chen JC

Water quality parameters, survival rates, and nervous necrosis virus (NNV) loadings of Epinephelus coioides grouper fry packed in 50 L bags after 24 h of simulated transport were examined. All fry packed at 300/bag and with water/oxygen ratios of 10 L/40 L, 12.5 L/37.5 L, and 15 L/35 L at 20°C survived with NNV loads of 4.1~7.9×104 at 7 d post-release in seawater. All fish packed at 300/bag and a water/oxygen ratio of 12.5 L/37.5 L at 20°C survived with an NNV load of 4.1×103, but fish packed at 25°C and 30°C survived 100% and 67.4%, and had NNV loads of 1.6×105 and 1.8×106, respectively at 7 d post-release. All fish packed at 200, 300, and 400/bag with a water/oxygen ratio of 12.5 L/37.5 L at 20°C survived with DO >5.0 mg/L, CO2 <95 mg/L, pH >5.8, and ammonia-N <11 mg/L, after 24 h. All fish packed at 200 and 300/bag survived with an NNV load of 1.7×103, whereas fish packed at 400 and 500/bag survived only 60.8% and 42.6% with NNV loads of 2.4×107 and 3.7×107, respectively at 7 d post-release. We concluded that grouper fry packed at 300/bag and a water/oxygen ratio of 12.5 L/37.5 L at 20 and 25°C were optimal for maintaining high DO (>5.8 mg/L) and pH (>5.6) and low CO2 (<89 mg/L), ammonia-N (<10.2 mg/L), and NNV loads (<4.9×103) after 24 h of simulated transport. The addition of zeolite increased DO and pH while lowering carbon dioxide and ammonia-N as well as lower NNV loads (2.3×103) during simulated transport.