Using marine fatty acid and stable isotope biomarkers to investigate overwintering diets of qavlunayagaat in the Unalakleet River watershed

The village of Unalakleet, Alaska lies at the mouth of the Unalakleet River (UR), which flows into Norton Sound in the Bering Sea. The UR is spawning grounds for neqarat (plural salmon), which is a staple food source for the indigenous people of the community. In recent years, there have been variable returns of neqarat to the UR. Many factors affect neqarat  survival, including predation and availability of food resources. Our study focuses on the importance of marine derived nutrients (MDN) to the overwinter body size and lipid content of qavlunayagaat (juvenile Oncorhynchus kisutch or Coho salmon), from the UR. To examine the relationship between MDN level, size, and lipid content, we collected qavlunayagaat (n=110) from the North River, a tributary of the UR, in March 2018. To assess MDN levels, qavlunayagaat were analyzed for fatty acid (FA) marine biomarkers (long chain polyunsaturated FA) and stable carbon and nitrogen isotope values (expressed as δ13C and δ15N). We hypothesize that elevated levels of MDN in qavlunayagaat will be positively correlated with body size and lipid content in winter.