Chinook Occurrence and Stock Origin along Coastal WA Relative to SRKW Phase II Update

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The U.S. Navy conducts military training and testing in Pacific Northwest range areas to prepare combat-ready military forces, whereas NOAA Fisheries is responsible for managing threatened and endangered species in marine waters and providing permits to the U.S. Navy. NOAA Fisheries and the U.S. Navy share the common goals of minimizing the impact of military training and testing activities on endangered species without compromising training and testing efforts and reducing adverse environmental effects. This work provides vital geographic and distributional data within the Navy’s range areas, allowing the Navy the flexibility to proceed with training and testing while providing protective measures for both salmonids and killer whales. This research jointly studied Chinook salmon and Southern Resident killer whales (SRKW) in the Northwest Training and Testing (NWTT study area) Range. The authors used acoustic telemetry to map salmon behavior and overlap with SRKW occurrence. By tracking Chinook salmon, SRKW's primary prey, the project aims to guide actions to conserve both species. The data will help adjust activities to minimize harm to these protected species. From May to September 2023, 101 Chinook salmon were caught, tagged, and released north of the Columbia River near the Washington Coast. Acoustic transmitters were surgically implanted into the fish, allowing them to be detected by stationary receivers deployed in the ocean, estuaries, and nearby rivers. The fish's locations and movements were recorded and used to Submitted in Support of the U.S. Navy’s 2023 Annual Marine Species Monitoring Report for the Pacific STANDARD FORM 298 Back (Rev. 8/98) assess their spatial distribution and behavior. SRKW detections were also collected from March to October 2023 at 15 passive acoustic moorings on the Washington coast. These acoustic moorings, in combination with the 69 kHz receivers, are currently in operation. All but one of the salmon tagged so far were Snake River spring/summer Chinook ESU and the remaining Chinook origin is yet to be determined. Tasks the are still to be completed include tagging an estimated 60 Chinook salmon and analyzing concurrently collected SRKW data. Spring-run Chinook salmon that are returning to the Columbia River are b