Influence of Size Upon the Adaptation of Steelhead Trout (Salmo gairdneri) and Chum Salmon (Oncorhynchus keta) to Sea Water

Abstract

Steelhead trout in the smolt phase of development adapted to sea water (salinity 22-24 parts per thousand) more rapidly and with less extensive departures from regulated conditions of water-electrolyte balance than did the larger post-smolts. By contrast, the extent and duration of the corresponding changes accompanying adaptation of juvenile chum salmon to sea water varied inversely with size. The data are discussed in relation to the distinction between smolting and non-smolting salmonid species.