Seasonal changes in the rigor of scallop adductor muscle

Changes in the frequency of specimens in rigor, ATP related compounds, L-ar ginine and octopine were examined in the adductor muscle of the scallop Pat inopecten yessoensis during storage at 0 degreesC. The scallop was caught i n June, September, November 1997 and April 1998 at Monbetsu. The scallop of September decreased in ATP concentration and pH, development of rigor, and increased in octopine, compared with the scallop of April. The development of rigor was different according to the seasons, affecting scallop quality . Sea water temperature was around harvesting areas 18.8 degreesC in Septem ber 1997 and 4.4 degreesC in April 1998. It is presumed that rigor of adduc tor muscle was induced by difference between sea water temperature of the h abitat of scallop and storage temperature.