News Release

Sneak copulations and the demise of the integrity of wild salmon populations

Peer-Reviewed Publication

Blackwell Publishing Ltd.

Releases of cultured organisms threaten native biodiversity and the integrity of natural communities. In species such as farm Atlantic salmon (Salmo salar L.) though, it was believed that the threat from the spread of domesticated traits in the wild was reduced by the relatively poor reproductive success of males escaping from marine netpens.

Recent evidence in a paper soon to appear in Ecology Letters by Garant, Fleming, Einum & Bernatchez, however, indicates that, similarly to wild salmon, the male offspring of farm spawners may mature precociously in freshwater, and use their small size to sneak copulations, darting in next to the female's ovipositor at spawning and fertilizing large numbers of eggs.

In fact, such farm males are more successful at sneaking copulations, participating in more spawning events and having higher fertilization success than wild males. The rapid maturity, combined with higher growth rates and reproductive performance of male offspring of farm origin, will thus not only perpetuate, but speed the gene flow from farm fish into native salmon populations.

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