Response of Pink salmon to climate warming in the northern Bering Sea

Abstract

Life-history and life-cycle models of Pink salmon (Oncorhynchus gorbuscha) are developed to provide insight into production dynamics of northern Bering Sea Pink salmon. Arctic ecosystems, including freshwater and marine ecosystems in the northern Bering Sea, are warming at a rapid rate. Due to their short, two-year life cycle, Pink salmon are well known to respond rapidly to ecosystem change and can provide unique insight into ecosystem impacts of warming Arctic conditions. Life-cycle models suggest a lack of density-dependence for adult Pink salmon spawners in the Yukon River and potential for some density-dependence for adult Pink salmon spawners in the Norton Sound region. Life-history models identify a positive and significant relationship between the abundance index for juvenile Pink salmon and average Nome air temperature during their freshwater residency (August to June). This relationship supports the notion that warming air temperatures in this region (as a proxy for river and stream temperatures) are contributing to improved freshwater survival or increased capacity of freshwater habitats to support Pink salmon production. Life-history models also identify the number of adult Pink salmon returning to Norton Sound and the Yukon River is significantly related to the juvenile abundance in the northern Bering Sea. This result indicates that much of the variability in survival for northern Bering Sea Pink salmon occurs during early life-history stages and that juvenile abundance is an informative leading indicator of Pink salmon runs to this region.