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Abundance, Growth, and Interactions of Juvenile Steelhead Relative to Time of Emergence
Author(s) -
Chandler G. L.,
Bjornn T. C.
Publication year - 1988
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(1988)117<0432:agaioj>2.3.co;2
Subject(s) - juvenile , fish <actinopterygii> , biology , salmo , fishery , rainbow trout , juvenile fish , zoology , ecology
Growth, interactions, and final densities of juvenile steelhead, Oncorhynchus mykiss (formerly Salmo gairdneri ) emerging early versus later were compared in laboratory stream channels. When the two groups of juveniles were held together 1–2 months, early emerging fish generally outnumbered late fish about 2 to 1. On any given date and at the end of the experiment, early fish were significantly longer and heavier than late fish. At the end of the test, late fish were more abundant in channels they occupied alone than in channels shared with early fish. Densities were higher when early and late fish were stocked together than when either was stocked alone because fish of the two groups occupied different parts of the habitat. Aggressive interactions (charges, attacks, and nips) observed were mainly between early fish rather than between early and late fish.