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Small‐scale spatial variation in age and size at maturity of stream‐dwelling brown trout, Salmo trutta
Author(s) -
Olsen E. M.,
Vøllestad L. A.
Publication year - 2005
Publication title -
ecology of freshwater fish
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 55
eISSN - 1600-0633
pISSN - 0906-6691
DOI - 10.1111/j.1600-0633.2005.00094.x
Subject(s) - salmo , allopatric speciation , brown trout , sympatry , sympatric speciation , streams , sexual maturity , biology , ecology , spatial variability , fishery , population , demography , computer network , statistics , mathematics , sociology , fish <actinopterygii> , computer science
– This study documents substantial small‐scale spatial variation in age and size at maturity of brown trout ( Salmo trutta ) found either in allopatry (above major waterfalls) or in sympatry (below waterfalls) with the Alpine bullhead ( Cottus poecilopus ) in forest streams in south‐east Norway. Within two streams, female brown trout above waterfalls tended to delay the onset of sexual maturity, as compared with females from neighbouring sites below the waterfalls. Four additional streams were represented with either an allopatric or a sympatric site. There was considerable variation in age and size at maturity among these streams, but no consistent difference between allopatric and sympatric sites. It is suggested that the spatial variation in maturity responses is influenced by local opportunities for growth, and possibly also survival. Earlier studies in these streams have linked spatial variation in brown trout behaviour and demography to the presence or absence of the Alpine bullhead.