Evaluating Factors Related to Inriver Adult Mortality in Copper River Sockeye Salmon

There are indicators that sockeye salmon (Oncorhynchus nerka) of the Copper River, an important population that supports subsistence fisheries in southcentral Alaska, is subjected to elevated inriver mortality during their spawning migration that may be linked to climate change. This mortality has implications for maintaining upriver escapement levels, representing a fundamental challenge to the management of subsistence fisheries in this region. This project will evaluate how changing body size, condition, and overall health of Copper River sockeye salmon may be related to inriver mortality. This work will inform fisheries management and provide insight into how harvest management might adapt to these changes in the future.

As the climate changes, addressing escapement quality, in addition to escapement quantity, is becoming an increasingly important component of contemporary fisheries management. The evaluation of the risk of inriver mortality and reproductive performance in CR sockeye will help managers determine if the discrepancy between lower and upper river escapement estimates could have a biological or ecological basis. This analysis could result in allowances for additional levels of escapement through harvest management to ensure sustainability of run-timing groups or populations that may be a concern, thus ensuring that subsistence opportunities are protected and maximized.