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Divergent trends in life‐history traits between Atlantic salmon Salmo salar of wild and hatchery origin in the Baltic Sea
Author(s) -
Vainikka A.,
KallioNyberg I.,
Heino M.,
Koljonen M.L.
Publication year - 2010
Publication title -
journal of fish biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.672
H-Index - 115
eISSN - 1095-8649
pISSN - 0022-1112
DOI - 10.1111/j.1095-8649.2009.02520.x
Subject(s) - salmo , biology , broodstock , hatchery , life history theory , fishery , life history , genetic divergence , salmonidae , smoltification , zoology , ecology , fish <actinopterygii> , aquaculture , demography , genetic diversity , population , sociology
Four Atlantic salmon Salmo salar stocks in the Baltic Sea, varying in their breeding history, were studied for changes in life‐history traits over the years 1972–1995. Total length ( L T ) at age of captured ( L TC ) fish had increased throughout the study period, partly due to increased temperature and increased L T at release, ( L TR ) but also due to remaining cohort effects that could represent unaccounted environmental or genetic change. Simultaneously, maturation probabilities controlled for water temperature, L TC and L TR had increased in all stocks. The least change was observed in the River Tornionjoki S. salar that was subject only to supportive stockings originating from wild parents. These results suggest a long‐term divergence between semi‐natural and broodstock‐based S. salar stocks. Increased L T at age explained advanced maturation only marginally, and it remains an open question to what extent the generally increased probabilities to mature at early age reflected underlying genetic changes.