Premium
Differences in the time of river entry of Atlantic salmon, Salmo salar L., spawning in different parts of the River North Esk
Author(s) -
SUMMERS D. W.
Publication year - 1996
Publication title -
fisheries management and ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.693
H-Index - 55
eISSN - 1365-2400
pISSN - 0969-997X
DOI - 10.1111/j.1365-2400.1996.tb00148.x
Subject(s) - salmo , tributary , fishery , fish <actinopterygii> , fish migration , biology , geography , cartography
Spawning adult Atlantic salmon, Salmo salar L., were sampled in five tributaries of the River North Esk, Scotland, during the winters 1989/90 and 1990/91. The fish furthest upriver had higher sea‐ and smolt‐ages and the one‐sea‐winter fish were smaller and more coloured than those spawning further downstream. These differences indicate that the uppermost tributaries are populated by fish which enter the river early in the year and the lowest tributaries by fish entering late in the year. Exactly why such a structure exists is not clear, but it is suggested that these differences may be adaptive and that selection effects may continually be modifying these populations.