Annual Report for the 2023 Port Moller Test Fishery

Executive Summary

In 2023, the Port Moller Test Fishery (PMTF) operated from June 11 to July 13 using two research vessels—the R/V Ocean Cat and the R/V Miss Leona. A total of 6,670 Sockeye were caught in 300 sets distributed across Stations 2-24 to provide the information used for inseason forecasting. An additional 12 sets made at and near Station 10 during June 19 and June 22 produced 414 Sockeye and helped to assess sampling error at a single station versus nearby patchiness in the passage rate. The coverage of stations and days during the 2023 test fishery was only surpassed by 2022, with only one day missed during mid-season due to weather. 

The email distribution list ended the season with 1,228 email addresses, up about 11% over 2022. The median time between sample collection and stock composition release to the distribution list was a single day during the 2023 season (similar to 2022); the maximum lag time was only two days. The turnaround time for 2023 estimates was about two days faster than what has been observed since 2010. Over the entire season a total of 12 estimates were released (about three more than in previous years). The reduced turnaround time between genetic tissue collection at the PMTF and release of the stock composition estimates, as well as increased frequency and number of estimates for 2022 and 2023 was due entirely to the onboard genetics lab that allowed genotyping to be done at sea. 

On June 20 and June 25, we estimated the weights of the average Sockeye passing the test fishing transect to be 5.6 lbs. These estimates agreed with the 5.5 lbs reported for inshore catch by ADF&G in their season summary. Likewise, the estimated age and stock compositions based on the PMTF reflected that of the inshore run very well. 

The 2023 run was 54.5 million with 50% of C+E occurring by July 6 making it 2-days late if July 4 is the date we use to reference an “average” run timing. Run timings over the previous eight years (2015-2022) have been late (mean=3.8 days late; range=1-6). The seasonal pattern in the 2023 run was similar to 2017 and 2021 in that a dramatic increase in C+E occurred in early July following a drop off in late June mostly due to the Nushagak-Wood District. Dissimilar to any other run going back to 2011, was the subsequent multimodal pattern having substantial peaks on July 10 and 14. Unlike other years when the outer stations were fished (2018-2022) a strong second mode of catches did not occur beyond Station 12. Although, catches did increase offshore slightly compared to inshore after June 30. 

Like 2022, the Daily Index was not indicative of the entry pattern for C+E during 2023. As such, we forewent publishing proximate forecasts of daily C+E during 2023. Seasonal shifts in the travel time (TT) between the test fishery and inshore likely caused fish to stack outside the districts before surging in causing the multimodal pattern in C+E that was not apparent in the Port Moller signal. Alternately, catchability unknowingly changed, which altered the return-perindex (RPI=the number of fish inshore that each catch index point at Port Moller represents). In other words, the passage rate increased more or less consistently and then subsided as the season progressed, but our ability to catch passing Sockeye likely fluctuated during the season.