Salmon are keystone species across the North Pacific, supporting ecosystems, commercial opportunities, and cultural identity. Nevertheless, many wild salmon stocks have experienced significant declines. Salmon restoration efforts focus on fresh and coastal waters, but little is known about the open ocean environment. Here we use high throughput RT-qPCR tools to provide the first report on the health, condition, and infection profile of coho, chum, pink, and sockeye salmon in the Gulf of Alaska during the 2019 winter. We found lower infectious agent number, diversity, and burden compared with coastal British Columbia in all species except coho, which exhibited elevated stock-specific infection profiles. We identified Loma sp. and Ichthyophonus hoferi as key pathogens, suggesting transmission in the open ocean. Reduced prey availability, potentially linked to change in ocean conditions due to an El Niño event, correlated with energetic deficits and immunosuppression in salmon. Immunosuppressed individuals showed higher relative infection burden and higher prevalence of opportunistic pathogens. We highlight the cumulative effects of infection and environmental stressors on overwintering salmon, establishing a baseline to document the impacts of a changing ocean on salmon.
Results of marine trawl surveys for accounting of pink salmon in 2021 and 2022 and the main results of the salmon fishery in 2022 are presented. The main stages of forecasting of the pink salmon fishery in the Far Eastern basin are described. Differentiation of mixed aggregations of pink salmon is discussed. In 2022, specialists of Kamchatka Branch used for the first time a new method based on variability of SNP loci, along with the traditional methods (morphological express-method and genetic method based on mtDNA analysis). This method provided additional dividing the mixed aggregations of autumn pink salmon in the Sakhalin-Kuril area to the herds from southern Kuril Islands and from eastern Sakhalin. The fishery forecasts for pink salmon were adjusted several times during the fishing season. These adjustments had no a significant effect for the catch increasing in the Okhotsk Sea basin, but allowed to land 10,500 t additionally in the Bering Sea.
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