The signature of fine scale local adaptation in Atlantic salmon revealed from common garden experiments in nature

摘要: Understanding the extent, scale and genetic basis of local adaptation (LA) is important for conservation management. Its relevance in salmonids at microgeographic scales, where dispersal (and hence potential gene flow) can be substantial, has however been questioned. Here, we compare fitness communally reared offspring foreign Atlantic salmon Salmo salar from adjacent Irish rivers reciprocal F1 hybrid crosses between them, wild ‘home’ environment population. Experimental groups did not differ smolt output but a catastrophic flood event may have limited our ability to detect freshwater performance differences, which were evident previous study. Foreign parr exhibited higher, hybrids intermediate, emigration rates natal stream relative parr, consistent with genetically based behavioural differences. Adult return lower compared group. Overall lifetime success foreigners locals was estimated 31% 40% (mean both groups), respectively. The results imply differences among populations separated by only 50 km, driven largely variation adult rates. Hence even if supplementary stocking programs obtain broodstock neighbouring rivers, risk extrinsic outbreeding depression high.