Changes in Allochronic Breeding Populations of Pink Salmon (Oncorhynchus Gorbuscha) of Prince William Sound, Alaska

Abstract

Prince William Sound, Alaska is home to one of the largest pink salmon (Oncorhynchus gorbuscha) fisheries in the world. Salmon populations there have been fished commercially for over a century, and the State’s documentation of commercial fishing provides a valuable dataset in order to examine abundance trends of species in this region. For this thesis research, I analyzed the fluctuations in abundance and isolated even year and odd year breeding populations of pink salmon to assess whether there is a numerical discrepancy between pink salmon that spawn in odd years and the population that spawns in even years. Analysis of these two populations showed differences in the abundance of pink salmon in even breeding years when compared to odd years. This research also indicated that there is a growing difference in the rate of increase of the odd and even year populations over the fifty-year span, 1968-2018. Increasing instability and differences between the two breeding populations may be the result of factors such as changing ocean temperatures, human intervention by way of fishing and artificial stock enhancement, and instances of environmental disaster and pollution in the region. Future research should investigate factors that may be resulting in these population differences.