DOI: 10.25921/x4cy-4w79
title: Catch per unit, CPUE, of Chum salmon collected from the fishing vessel Nita Maria in Strait of Juan de Fuca for Joint US and CA Juan de Fuca Chum Sampling Program 2022 from 2022-09-26 to 2022-11-03 (NCEI Accession 0299597)

description: This dataset contains only the final cruise report describing Chum salmon survey in Strait of Juan de Fuca in autumn 2022. The project plan for 2022, the seventh year of the project, was very similar to previous years. Once approvals were obtained for clearance to fish in both US and Canadian waters, the vessel Nita Maria was chartered to fish based on a 4 day per week schedule (2 days in Canadian waters and 2 days in US waters) for a 6-week period starting the 1st week of October.

Through the initial work on the ChumGEM reconstruction model, it was very apparent that the diversion of Chum salmon stocks through the southern route (Strait of Juan de Fuca) was a significant gap in our information needed to populate the model. Currently the model structure is available to incorporate this information but the assumptions on the migration pathways being used require investigation and validation.

The purpose of this project was to work towards addressing that data gap by sampling this migration route in both US and Canadian waters to determine:
• The spatial and temporal stock composition of Chum salmon migrating through the Southern Diversion route,
• Provide sampling platform for stock identification, migration rate studies etc.
• Develop time series of Catch per Unit effort data to pair with the Johnstone Strait Test Fishery to determine diversion rate of various Chum populations.

The program began as planned on September 26th and ran until November 3rd. A total of 142 sets were completed (70 in Canadian waters and 72 in US waters). A total of 2,216 Chum was encountered and 1,683 were sampled for stock id and other biologicals. The Catch per Unit Effort (CPUE) was generally stronger on the Canadian side in the first few weeks and then shifted to a more dominant US CPUE for the rest of the program., like what was seen in 2017, 2018 and 2021. The catch information demonstrated a peak timing during week 44 which we observed in only one other year (2016). Typically, peak weeks were week 42 or 43 and this later shift in CPUE was attributed to an improved return of Chum to both Hood Canal and Puget Sound. The 2022 Chum CPUE was the 4th lowest over the 7-year program and only slightly better than what was observed in 2016.

Low Chum abundance in 2022 resulted in not collecting weekly sample size targets (except Week 44 in US waters). Interpretation of some of the weekly biological data should be approached with caution due to some very small sample sizes. Stock composition information demonstrated that Canadian Chum stocks, over the duration of the program, dominated the samples throughout the Canadian waters. US Chum stocks in Canadian waters varied in composition but increased later in the program. In US waters, US Chum stocks dominated the mixtures throughout the program all weeks sampled. Stock timing and distribution differences were observed, and this new information has improved our understanding of Chum stock composition and timing through the migratory pathways of Juan de Fuca Strait.

It is hoped that with additional years of Chum CPUE data from this Southern approach (through Juan de Fuca) it will help to improve the existing relationship between Chum CPUE and abundance that exists for the Northern Approach (through Johnstone Strait).

This cruise is U.S. State Department MSR U2022-042 as part of the World Data Service for Oceanography. Final cruise report is in PDF.