TEMPERATURE-INDUCED AND DEVELOPMENTALLY-INDUCED VARIATION IN THE HISTOCHEMICAL PROFILE OF MYOFIBRILLAR ATPASE ACTIVITY IN CARP

The histochemical profile of calcium activated acid stable myofibrillar ATPase (mATPase) activity in developing larval and juvenile carp was investigated. In the larval fish, differentiation of pink muscle fibres occurred after metamorphosis which was delayed by a week at 17 degrees C compared to larvae grown at 27 degrees C. After metamorphosis the 27 degrees C group exhibited some small myofibres with acid stable mATPase activity in the deep white muscle. This was similar for the juvenile carp which were acclimated for more than a month at 25 degrees C. In contrast, the cold (12 degrees C) acclimated juvenile fish, contained very few small white muscle fibres with acid stable mATPase activity. It was also noted that the cold acclimated fish had lower background acid stable mATPase activity than the warm acclimated fish. Results indicate that after metamorphosis and more evidently in juveniles, temperature can influence the rate of myofibre hyperplasia. (C) 1995 The Fisheries Society of the British Isles.