The influence of artificial selection on the spawning behaviour and reproductive success of male Atlantic salmon, Salmo salar

This thesis explores questions related to the genetic basis of, and the effect of artificial selection on, variation in reproductive behaviour of male Atlantic salmon, Salmo salar. Specifically, I compare and contrast spawning behaviour and reproductive success of Atlantic salmon of farmed and wild origin. Two distinct maturation phenotypes are expressed by male Atlantic salmon: some mature at a small size in fresh water without migrating to sea (mature male parr), and others mature at a considerably larger size following feeding periods in the ocean ( anadromous males). Anadromous males typically compete aggressively for females and form a behavioural dominance hierarchy, whereas mature male parr attempt to sneak fertilisations. In three experiments, males of farmed and wild origin competed for spawning opportunities in a simulated river environment. In addition to investigating individual behavioural differences within farmed and wild anadromous males, the primary experiment also examined direct competition among wild, F₁ hybrid, and 7th generation farmed mature male parr raised under similar hatchery conditions. (Abstract shortened by UMI.)...