Alterations in the Blood Level of Lactic Acid in Certain Salmonoid Fishes Following Muscular Activity.: III. Sockeye Salmon,<i>Oncorhynchus nerka</i>

Abstract

The blood level of lactic acid in hatchery-raised sockeye salmon, Oncorhynchus nerka, was studied following 15 minutes of vigorous muscular activity. Yearling salmon acclimated and exercised in fresh water showed a sevenfold increase in blood lactic acid following activity, increasing still further during the first two hours of recovery, as in the Kamloops trout, Salmo gairdneri. Yearling salmon acclimated in sea water for two days and then exercised exhibited higher immediate increase in lactic acid and showed less fatigue. The sea water appeared to aid the yearling salmon in coping with fatigue products. However, two-year-old salmon that had been acclimated a year and a half in sea water showed the same change in lactic acid following exercise as the yearlings in fresh water. Five of 19 two-year-old salmon died following the exercise.