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Physiological seawater adaptation in juvenile Atlantic salmon ( Salmo salar) autumn migrants
Author(s) -
RILEY W. D.,
IBBOTSON A. T.,
LOWER N.,
COOK A. C.,
MOORE A.,
MIZUNO S.,
PINDER A. C.,
BEAUMONT W. R. C.,
PRIVITERA L.
Publication year - 2008
Publication title -
freshwater biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.297
H-Index - 156
eISSN - 1365-2427
pISSN - 0046-5070
DOI - 10.1111/j.1365-2427.2007.01933.x
Subject(s) - salmo , spawn (biology) , juvenile , fishery , smoltification , biology , juvenile fish , habitat , fish migration , fish measurement , salmonidae , ecology , fish <actinopterygii>
Summary1 About 25 % of juvenile Atlantic salmon ( Salmo salar ) migrating downstream in the River Frome in southern England do so in the autumn rather than in the spring. Here, we examine the physiological status of these fish with regard to those features that adapt them to sea water during the parr–smolt transformation (i.e. gill Na + K + ATPase activity; the number, size and type of chloride cells on the gill lamellae; salinity tolerance and relative plasma thyroid levels). 2 Autumn migrants, and those fish which subsequently reside in the tidal reaches during the winter, are not sufficiently physiologically adapted to permit permanent or early, entry into the marine environment. 3 It is not known what proportion of autumn migrating fish survive and return to spawn as adults. If significant numbers do return, however, the production from tidal reach habitats must be taken into account in the development of salmon stock management strategies, especially monitoring and assessment programmes, and in the evaluation of factors affecting stocks.