Alternative male life-history tactics as potential vehicles for speeding introgression of farm salmon traits into wild populations

Dany Garant,* Ian A. Fleming,* Sigurd Einum* and Louis Bernatchez Département de Biologie, Université Laval, Ste-Foy, Québec, Canada Coastal Oregon Marine Experiment Station and Department of Fisheries and Wildlife, Oregon State University, Hatfield Marine Science Center, Newport, OR, USA Norwegian Institute for Nature Research (NINA), Trondheim, Norway Correspondence and present address: Dany Garant, Department of Zoology, Edward Grey Institute, University of Oxford, South Parks Road, Oxford, UK E-mail: dany.garant@ zoology.oxford.ac.uk *These authors contributed equally to this work. Abstract Releases of cultured organisms, such as farm Atlantic salmon (Salmo salar L.), threaten native biodiversity and the integrity of natural communities. Salmon escaping from sea farms, however, have relatively poor reproductive success, suggesting that the rate of spread of domesticated traits may be reduced. We now compare the relative reproductive success of males that mature precociously in freshwater (parr) and find that those of farm origin have higher breeding and fertilization success than wild and hybrid individuals. Specifically, hybrid parr had 57% and wild parr 25% the success of farm parr. Early maturing males could thus be important vehicles promoting introgression of domesticated and/or non-native traits into wild populations and ultimately have longterm impact on the genetic integrity of native populations.