The Growth of Brown Trout (<i>Salmo Trutta</i> Linn.)

Abstract

ABSTRACT Since fish form an important source of human food, a considerable amount of data is available concerning their distribution and size under natural conditions. This is especially true for the Salmonidae because of their popularity with sporting fishermen. With the development of commercial hatcheries, there has been a certain amount of experimental work concerning the effect of various factors on the growth and life history, particularly of ‘trout’—Salmo trutta, S. irideus and Salvelinus fontinalis. However, it is impossible to define the effect of any particular factor on trout growth, since several environmental factors varied at the same time, without being measured accurately. In some experiments (Surber, 1935; Pentelow, 1939) individual trout were isolated and their growth recorded, while in others (McCay &amp; Tunison, 1935, 1937; Wingfield, 1940) the fish were kept in groups and their average sizes recorded at intervals. There is thus no record of the effect of intraspecific relationships on the growth of individuals.