The effect of packing on water quality parameters, survival and NNV load of Epinephelus coioides fry after simulated transport

Abstract

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 5.8, and ammonia-N 5.8 mg/L) and pH (>5.6) and low CO2 (<89 mg/L), ammonia-N (<10.2 mg/L), andNNV loads (<4.9×103) after 24 h of simulated transport. The addition of zeolite increased DO and pH while loweringcarbon dioxide and ammonia-N as well as lower NNV loads (2.3×103) during simulated transport.