Forecasts from the University of Washington Alaska Salmon Program (UW-ASP) and Alaska Department of Fish and Game (ADF&G) foresee a 2023 Bristol Bay sockeye salmon harvest of 35 million to 38 million, compared to the 2022 harvest of 60 million fish.
Forecasts differ due to the modeling used by researchers at the two entities.
The UW-ASP preseason forecast, based on historical catch and escapement data collected by ADF&G, plus additional stock, plus 38 individual stocks by age class forecasts, is lower than the recent 10-year average of 57 million fish and 4% higher than the recent 20-year average of observed runs of 48 million sockeyes to Bristol Bay.
In recent years, the UW-ASP program has increasingly relied on Dynamic Linear Models (DLM) to generate forecasts based on their performance, UW researchers said. DLMs are sibling models in which both the intercept (average production of the forecasted stock-age group) and co-efficients describing the relationship between younger and older sibling age classes, are allowed to evolve over time.
More information on the overall UW-ASP program is online at https://alaskasalmonprogram.org.
ADF&G research biologists are predicting a run of 51.07 million red salmon into Bristol Bay and a range of 36.58 to 65.56 million fish, with a harvestable Bristol Bay surplus of 36.66 million fish and 1.41 million red salmon into the South Alaska Peninsula.
That forecast is 10% smaller than the most recent 10-year average of Bristol Bay total runs of 57.24 million fish and 40% greater than the 1963-2022 average of 36.53 million fish.
Since 2001, the forecasts have on average under-forecast the run by 14%, ranging from 44% below the actual run in 2014 to 19% above the run in 2011.
The state’s 2023 forecast is the sum of individual predictions of nine river systems: the Kvichak, Alagnak, Naknek, Egegik, Ugashik, Wood, Igushik, Nushagak and Togiak rivers; and four age classes, including 1.2, 1.3, 2.2 and 2.3.
Preliminary data on the 2022 Bristol Bay commercial salmon season showed that the in-shore run of sockeyes was 79 million fish, the largest in-shore run on record, and 81% above the 43.6 million average run for 2002 to 2021.
It also was just the fourth time on record that the in-shore sockeye run exceeded 60 million fish.
Runs to every district except Togiak were larger than the preseason forecast. The commercial harvest of 60 million sockeyes was essentially the same as the 59.9-million preseason forecast. The previous record harvest was 44.3 million red salmon in 1995.
More details on the ADF&G forecast are online at https://tinyurl.com/3dcaee8m.