1Kagoshima Prefecture Fisheries Technology and Development Center, Ibusuki, Kagoshima 891-0315, 2National Research Institute of Aquaculture, Minami-Ise, Mie 516-0193, 3National Fisheries University, Shimonoseki, Yamaguchi 759-6595, 4Faculty of Fisheries, Kagoshima University, Shimoarata, Kagoshima 890-0056, Japan.
Instantaneously-killed spotted mackerel Scomber australasicus which had rested in a fish cage for a few days before being killed maintained a higher flesh quality for a longer time postmortem, and contained a high content of ATP in muscle after cooling in ice for 9 h.
To elucidate the effects of resting in a fish cage on the flesh quality of spotted mackerel caught by a purse seine, the muscle, blood and liver metabolites after exhaustive exercise for 20 min by hauling with a net using fish that had previously rested well in a fish cage were monitored over a 72-h period. The concentrations of plasma cortisol in blood and lactate in muscle increased with the exercise, and then decreased during resting for 72 h. The glycogen content in liver also recovered during resting. The ATP content in muscle immediately after the exercise was, however, elevated.