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Growth of Brown Trout in Selected Pennsylvania Streams
Author(s) -
Beyerle George B.,
Cooper Edwin L.
Publication year - 1960
Publication title -
transactions of the american fisheries society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.696
H-Index - 86
eISSN - 1548-8659
pISSN - 0002-8487
DOI - 10.1577/1548-8659(1960)89[255:gobtis]2.0.co;2
Subject(s) - salmo , brown trout , trout , streams , zoology , biology , population , growth rate , body weight , fish <actinopterygii> , fishery , ecology , demography , mathematics , computer network , sociology , computer science , geometry , endocrinology
Samples of age‐groups O and I fish from wild populations of brown trout (Salmo trutta Linnaeus) indicated a similarity in the periodicity of growth in three streams in Pennsylvania. Growth in length of trout of both age groups followed a similar pattern in the three streams, with the most rapid growth occurring in the spring and very little growth occurring in the winter months. Estimates of the mean total length at the end of two complete growing seasons were 7.0, 7.8, and 8.5 inches, respectively, for the three streams. Values of the exponent b of the customary length‐weight formula were similar among the three populations, varying from 2.94 to 3.01. Annual variations in condition of the trout were also similar in the three streams. An increase in condition in the spring coincided with an increase in growth rate; a drop in condition in fall and winter was accompanied by slower growth. The trout population in Spruce Creek had the highest average condition throughout the year. This population also had a significantly greater mean length than the other two at the end of the 2‐year period. The specific growth rate in weight of age‐group O trout in Spruce Creek declined from a high of 5.6 percent of their body weight per day in early June to negative values in November and December. During the second summer of life the specific growth rate increased to a high of 3.1 percent per day in April and subsequently decreased to a very low value in fall and winter.