Farmed-Wild Atlantic Salmon Interactions: Synopsis
Unprecedented declines in Atlantic salmon in eastern North America, coupled with ever-increasing production of salmon in aquaculture farms, has raised questions concerning the degree to which interbreeding between farmed salmon escapees and their wild counterparts affects individual fitness and the probability of persistence of wild salmon populations. For example, gene flow from artificially-selected organisms to wild relatives may lead to outbreeding depression, such that the fitness of the hybrid offspring, or subsequent-generation offspring, is reduced, the consequences of which could include population reduction or extinction. If the rate of gene flow is sufficiently high, introgression of genetic material into wild relatives could lead to the permanent alteration of original genotypes of wild individuals. Using offspring produced from multiple pure and hybrid crosses, after one and two generations of interbreeding, common-garden experiments are employed to study the fitness consequences of interbreeding between wild and farmed Atlantic salmon.