Studies on freshness of trawl catches. V. The influence of habitat water temperature on the relative thermostability of myofibrillar Ca2+-ATPase in fishes collected in the waters from tropical to frigid zones.

Abstract

The first order rate constants, KD, of thermal inactivation of myofibrillar Ca2+-ATPase were determined for a total of 79 fishes of 50 families caught from six waters covering from the tropical waters, 28°C in a bottom water temperature, to the cold waters, 2°C. The mean value of KD for fishes from a certain fishing ground tended to be lower with a higher habitat temperature; the value was lowest for the fishes from the Gulf of Thailand (28°C in the habitat temperature), followed by fishes from northern waters in the order of the adjacent waters of Amami-Oshima (25°C), Sakishima Islands (28°C), the East China Sea (17°C), the Yollow Sea (9°C), and off Kushiro (2°C). A significant, negative, logarithmic functional correlation was seen between the bottom water temperature of a fishing ground (t) and the mean value of KD for fishes inhabiting there (-KD); their rela-tion is formulated as below. ln KD=-0.1013t+5.611 Similar influences of habitat temperatures on KD were also seen for a fish from two areas of different habitat temperatures, though the degree of the influence was somewhat variable by fish species. Fishes with higher values of ΔK32, the increasing rate of K value, tended to show higher values of KD.