Growth of Fishes in Different Salinities

Abstract

Sizes attained by several species of fish inhabiting both sea and fresh waters suggest that the larger size of the marine form is due to the higher osmotic content of the medium. This theory was tested experimentally by comparing fresh and saltwater growth of juvenile coho, sockeye and chum salmon and adult goldfish. Such factors as temperature and food were rigidly controlled. In general, the salmonids (coho, chum or sockeye underyearlings) grew more rapidly in saline than in fresh water. Adult goldfish did not show any significant difference in weight increase.