Gulf of Alaska | Fishes and Fish Habitats
A possible cryptic ecotype in wild Alaskan pink salmon ( O. gorbuscha ): Fine-scale homing to intertidal or upstream habitats Presenter: Samuel May , samay3@alaska.edu, University of Alaska Fairbanks Peter Westley , pwestley@alaska.edu, UAF The homing ability of salmonids facilitates local adaptation, shapes the ecology and evolution of populations, and can complicate fisheries management across large spatial areas. However, the fine-scale resolution at which homing occurs remains largely unknown. Addressing the scale of homing has important implications for rates of inbreeding, the extent of local adaptation, and the amount of gene flow within populations. There is growing evidence in some species of salmon that individuals may return within short distances from where they hatched, yet pink salmon populations are often considered the most genetically homogenous salmonid species due to high dispersal rates. Pink salmon are also the only species of salmonid known to frequently spawn in intertidal (saline) environments. Here we examine several populations of pink salmon in Prince William Sound, Alaska to determine if individuals are returning to natal sites based on salinity barriers. We compared the spawning locations of offspring to the spawning location of parents using mixed effect models on pedigree datasets of returning adult spawners, while accounting for life-history variation such as sex, size, and return timing. We found that individuals reared in intertidal environments tended to return to intertidal environments, whereas individuals reared in freshwater tended to return upstream. We believe these results particularly relevant given the high incidence of hatchery-origin pink salmon, reared in freshwater hatchery environments, that stray into wild populations in Prince William Sound. Here, we discuss these results in the context of implications for gene flow, local adaptation, and hatchery-wild interactions within populations.
Alaska Marine Science Symposium 2023 183
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