Genome-wide analysis reveals demographic and life history patterns associated with habitat modification in land-locked, deep-spawning sockeye salmon (Oncorhynchus nerka)

Human-mediated habitat fragmentation in freshwater ecosystems can negatively impact genetic diversity, demography and life history of native biota, while disrupting the behaviour of species that are dependent on spatial connectivity to complete their life cycles. In the Alouette River system (British Columbia, Canada), dam construction in 1928 impacted passage of anadromous sockeye salmon (Oncorhynchus nerka), with the last records of migrants occurring in the 1930’s. Since that time, O. nerka persisted as a resident population in Alouette Reservoir until experimental water releases beginning in 2005 created conditions for migration; two years later, returning migrants were observed for the first time in ~70 years, raising important basic and applied questions regarding life history variation and population structure in this system. Here, we investigated the genetic distinctiveness and population history of Alouette Reservoir O. nerka using genome-wide SNP data (n=7,709 loci) collected ...