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Microhabitat Use and Behavior of Overwintering Juvenile Coho Salmon in a Lake Superior Tributary
Author(s) -
Healy Brian D.,
Lonzarich David G.
Publication year - 2000
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(2000)129<0866:muaboo>2.3.co;2
Subject(s) - oncorhynchus , overwintering , tributary , juvenile , streams , fishery , habitat , chinook wind , range (aeronautics) , ecology , environmental science , geography , fish <actinopterygii> , biology , computer network , materials science , cartography , computer science , composite material
Little is known about the behavior of coho salmon Oncorhynchus kisutch established in the Lake Superior drainage in the late 1960s. Unlike in their native range of the Pacific coast, Lake Superior coho salmon juveniles inhabit streams characterized by low winter flows and highly variable summer flows. Because high stream flows can profoundly affect fish behavior and distribution, we hypothesized that the winter ecology of coho salmon in Lake Superior streams would differ from patterns described for Pacific coast populations. Snorkeling surveys completed in winter 1998 examined the distribution and social organization of overwintering coho salmon in simple and complex pools of a Lake Superior tributary in Wisconsin. In both habitat types, coho salmon occupied focal positions in the main channel; however, fish were more tightly distributed and closer to the streambanks in simple pools. Aggressive interactions also were more common in simple pools. These results contrast sharply with research findings from Pacific coast streams, which generally show juvenile coho salmon moving to protected habitats and becoming less aggressive in winter. This study provides new insights into the behavioral plasticity of coho salmon and may aid in efforts to manage Great Lakes coho salmon populations.