2019 Run Timing Outlook and Forecast Summary: Chinook Salmon, Yukon River Delta

UPDATE: Read the post-season analysis. The 2019 actual run timing was not all that far off the preseason forecast.

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This timing and environmental information is intended for use 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 2019. The outlook and its associated forecast are based on the historical fish and environmental variables for which the data are given below. Contained on this page will be (1) the modeled and estimated cumulative daily percentage of the 2019 Chinook salmon run, (2) the cumulative CPUE of the delta test fisheries, as reported daily in 2019 by ADF&G compared to a selection of cumulative CPUEs of historical runs, and (3) marine environmental data (charts below) that are used as inputs to the 2019 outlook and forecast model. As data on the fish migration data develop, they will be plotted on Chart 1 so it can be seen how well the actual run matches the model and forecasts. When the timing model doesn’t match the actual run, the timing model and forecasts may be updated.

Chart 1. Forecast of the cumulative percent of the Chinook run in Y-1 on each date from June 1 through July 15, 2019. Blue bars are forecasts of the 15%, 25% and 50% run percentiles derived from a model that approximates the migration of 1985. Once the run starts, a cyan-colored line will show the 2019 cumulative CPUE converted to estimated run percentages.

Use this link if you can’t see the graph.

Chart 2. Historical CPUE data provided by Arctic-Yukon-Kuskokwim Region, Alaska Department of Fish and Game. The blue line at the center of the graph shows the average of all runs between 1989 and 2011, excluding 2009 and 2010.

Use this link if you can’t see the graph.

Near Real-Time Marine Environmental Variables

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

April Mean Air Temperature Nome:

Marine Surface Temperature (°C) 26.5 mi due west of Nunaktuk Island (Middle Mouth) (63.1°N 165.5°W)

May Mean Sea Surface Temperature:

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

Mean Ice Cover, March 20–June 1:

Winds measured at Emmonak Airport (mph)