The Effects of Male Dominance, Secondary Sexual Characteristics and Female Mate Choice on the Mating Success of Male Atlantic Salmon Salmo salar

Authors

  • Torbjörn Järvi

    Corresponding author
    1. Norwegian Institute for Nature Research, Ims, Sandnes
      Norwegian Institute for Nature Research, Research Station for Freshwater Fish, Ims, N-4300 Sandnes, Norway.
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    • 2

      Jarvi, T. 1990: The effects of male dominance, secondary sexual characteristics and female mate choice on the mating success of male Atlantic salmon Salmo salar. Ethology 84, 123–132.


Norwegian Institute for Nature Research, Research Station for Freshwater Fish, Ims, N-4300 Sandnes, Norway.

Abstract

The reproductive behaviour of male and female Salmo salar was studied in a specially constructed arena.

The Results showed that body size, cardiac-somatic index and relative kype size were all correlated with male dominance rank. Dominant males approached ripe females more frequently and ultimately mated more frequently than subordinates. Males repelled by females from the spawning beds had smaller adipose fins. No correlation was found between female aggression and male dominance, body size or cardiac-somatic index. The results suggest that male salmon establish a dominance hierarchy during the spawning period and that intra-sexual selection has favoured the evolution of a status signalling system, whereby males signal their dominance rank by their relative kype size. Dominant males having conspicuous secondary sexual characteristics are able to mate more frequently because they can occupy ripe females. As females seem to select their mates on grounds of the relative size of the adipose fin, inter-sexual selection is also presumed to have affected the evolution of male secondary sexual characteristics.

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