2012 Run Timing Outlook and Forecast Summary: Chinook Salmon, Yukon River Delta

This page summarizes historical and near real-time fish and environmental data for the 2012 Chinook salmon run in the Yukon River delta, Alaska Department of Fish and Game (ADF&G) Area Y-1. This information may be used by fishery managers, residents of Yukon River communities, and others to estimate when the Chinook salmon run will arrive on the delta and how it will develop through June and July 2012. Contained on this page are: (1) the modeled and estimated cumulative percents of the 2012 Chinook salmon run, (2) the cumulative catch per unit effort (CPUE) for 2012, calculated by combining numbers from the Big Eddy and Middle Mouth test fisheries, compared to a selection of historical runs, and (3) marine environmental data that were used as inputs to the forecast model.

Update June 18, 2012: The pre-season forecast model based on marine environmental variables has been replaced by a fit of the model to the 1985 pattern of test fishing CPUE (Chart 1). The year 1985 was chosen as the best fit to the 2012 CPUE among years since 1980. The 2012 Chinook migration is turning out to be one of the latest, if not the latest, on record. The pre-season forecast of June 20 for the first pulse of Chinook does not appear realistic given the catch per unit effort (CPUE) of the combined Y-1 test fishing sites through June 17. As shown in Chart 1, significant movement of Chinook should be evident by June 23, with the first pulse of Chinook for 2012 now expected to occur June 26.

Chart 1. Forecast of the cumulative percent of the Chinook run in Y-1 on each date from June 1 through July 15, 2012. Blue bars are forecasts of the 15%, 25% and 50% run percentiles derived from a model that approximates the migration of 1985. The orange line shows 2012 cumulative CPUE converted to estimated run percentages.

Chart 2. 2012 Cumulative test fishery CPUE (orange) compared to historical CPUE data provided by Arctic-Yukon-Kuskokwim Region, Alaska Department of Fish and Game. The earliest run was observed in 1996 (green), and the latest run was observed in 1985 (red). Also shown are the average of all runs between 1989 and 2011 except 2009 (blue), and the 2010 run (purple), which looks like it may be analogous to the 2012 forecast.

Near Real-Time Marine Environmental Variables

Air Temperature (°F) for Nome and Emmonak, AK

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April Mean Air Temperature Emmonak: -6.26 (°C)

April Mean Air Temperature Nome: -6.44 (°C)

Marine Surface Temperature (°C) for 63.1°N 165.5°W

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May Mean Sea Surface Temperature: -3.29 (°C)


Average Sea Ice Concentration (%) for 62–63°N, 166–169°W

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Mean Ice Cover, March 20–June 1:


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