Finding Evidence for Local Adaptation In Atlantic Salmon and Brown Trout: Using a Common Garden Experimental Approach In the Wild

Finding evidence for local adaptation in Atlantic salmon (Salmo salar) and brown trout (Salmo trutta) using a common garden experimental approach in the wild.

 

Philip McGinnity, Paulo Prodohl, Andy Ferguson, Ciar O’Toole, Deirdre Cotter, Jamie Coughlan & Tom Cross.

 

Direct experimental evidence of local adaptation and the scale at which it is evolutionarily and biologically significant is difficult to obtain. Yet, if the considerable logistical difficulties and costs associated can be surmounted, with perseverance such experiments (e.g. common garden experiments) provide the most parsimonious way of measuring and providing convincing evidence for local adaptation.  Here we report on progress in three new and ongoing large scale common garden experiments being undertaken in the wild, using genetic markers, for Atlantic salmon (Salmo salar) and the brown trout (Salmo trutta).  One of these experiments is a full reciprocal transfer experiment of the progeny of two salmon populations, originating from two rivers, located within a small geographical area (50Km²) and their respective hybrid progeny. In addition we will also review previously reported common garden experiments, insights garnered from the long-term monitoring of a single salmon population and the use of a genetic stock identification (GSI) approach for elucidating the links between qualitative genetic structure as defined by neutral genetic markers and quantitative (possibly adaptive) differences between salmon populations in a large river system. These investigations should go some way to furthering the dialogue on how research on local adaptation and life history ecology may play a role in the conservation of salmonid populations.