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Growth and Production of Sympatric Brook and Rainbow Trout in an Appalachian Stream
Author(s) -
Whitworth Wilbur E.,
Strange Richard J.
Publication year - 1983
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(1983)112<469:gaposb>2.0.co;2
Subject(s) - sympatric speciation , rainbow trout , fishery , sympatry , biology , ecology , fish <actinopterygii>
A small, second‐order stream in the southern Appalachians was sampled every 2 months from September 1978 to October 1979. The 1.5‐km study segment was divided into 50, 30‐m sections grouped into three areas: A downstream area with only rainbow trout Salmo gairdneri; a middle, mixed‐trout area; an upstream area with predominantly brook trout Salvelinus fontinalis. Although a few fish of both species exhibited substantial movements, the majority of fish moved less than 30 m either upstream or downstream. Growth rates of both species were approximately equal until the spring of their second year, when rainbow trout outgrew brook trout and thereafter maintained a size‐at‐age advantage. Rainbow trout, particularly the 1978 cohort, dominated trout production in the stream. Even in the brook trout area, where the density of 1978 cohort brook trout was twice that of 1978 cohort rainbow trout, rainbow trout outproduced brook trout by 1.20 g/m 2 to 1.14 g/m 2 . Declining mean biomass of older fish of both species indicates high winter mortality. This, accompanied by slow growth of older fish, resulted in very few fish of either species entering the legal fishery. Received November 27, 1981 Accepted April 24, 1983