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Summer Survival and Growth of Brown Trout with and without Steelhead under Equal Total Salmonine Densities in an Artificial Stream
Author(s) -
Kocik John F.,
Taylor William W.
Publication year - 1994
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(1994)123<0931:ssagob>2.3.co;2
Subject(s) - brown trout , intraspecific competition , salmo , trout , interspecific competition , biology , rainbow trout , fishery , competition (biology) , ecology , zoology , fish <actinopterygii>
We studied the survival and growth of age‐0 brown trout Salmo trutta with and without age‐0 steelhead Oncorhynchus mykiss , under conditions of equal salmonine density (numbers per unit area), to compare the relative effects of intraspecific and interspecific competition. We conducted these experiments from June through September in an artificial stream with recirculating water and used a replicated, completely randomized design. The experiment was initiated with four allopatric treatments of 14 brown trout each and four sympatric treatments of 7 brown trout and 7 steelhead each. Mortality during the experiment resulted in variable densities among replicates. Interactions with steelhead did not have negative effects on brown trout survival or growth. A model comparing the effects of total salmonine, steelhead, and brown trout densities on brown trout length suggested that intraspecific interactions had the strongest influence. Our results indicate that the steelhead did not influence the brown trout survival or growth during the summer growth period to the same extent as an equivalent number of brown trout. However, we recommend caution in combining these two species until the implications of interactions at other life history stages are examined.