Small-scale spatial variation in age and size at maturity of stream-dwelling brown trout, Salmo trutta

Authors: Olsen, E. M.; Vøllestad, L. A.

Source: Ecology of Freshwater Fish, Volume 14, Number 2, June 2005 , pp. 202-208(7)

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Abstract:

Olsen EM, Vøllestad LA. Small-scale spatial variation in age and size at maturity of stream-dwelling brown trout, Salmo trutta. Ecology of Freshwater Fish 2005: 14: 202–208. © Blackwell Munksgaard, 2005 Abstract –

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.

Keywords: age at maturity; brown trout; Salmo trutta; size at maturity; spatial variation

Document Type: Research article

DOI: http://dx.doi.org/10.1111/j.1600-0633.2005.00094.x

Publication date: 2005-06-01