Migration effort and wild population size influence the prevalence of hybridization between escaped farmed and wild Atlantic salmon

EVA Sylvester,LC Hamilton,SJ Duffy,IA Fleming,BF Wringe,IR Bradbury

doi:10.3354/aei00277

Abstract

Migration effort and wild population size influence the prevalence of hybridization between escaped farmed and wild Atlantic salmon

Highlights

Farmed Atlantic salmon Salmo salar differ both genetically and phenotypically from their wild counterparts due to breeding practices, domestication selection, random drift during domestication, and© I
Regardless of the mechanism involved within-river variation observed in the present study demonstrates that sampling from multiple sites within rivers is likely to improve estimates in future work of the frequency of hybridization and introgression between wild Atlantic salmon and farmed escapees
We have demonstrated that smaller wild populations are most at risk of detrimental genetic effects from farmed introgression due to increased presence of hybrid and feral parr in smaller rivers

Summary

INTRODUCTION

Farmed Atlantic salmon Salmo salar differ both genetically and phenotypically from their wild counterparts due to breeding practices, domestication selection, random drift during domestication, and. Estimates suggest that the number of escaped individuals may outnumber that of wild salmon annually in the North Atlantic (Glover et al 2017), with reports of interactions with native populations (Hindar et al 2006, Glover et al 2013, Karlsson et al 2016). Possible consequences of these interactions include increased competition for resources (Skaala et al 2012), exposure to introduced disease and pathogens, and outbreeding depression (McGinnity et al 2003). We extended this previous research with a novel investigation of potential fine-scale landscape influences on hybridization in the region following this escape event and subsequent trickle escapes

MATERIALS AND METHODS

RESULTS

DISCUSSION