2016: Post Season Analysis Outlook and Forecast for Yukon Chinook Salmon Timing

The 2016 Post Season Analysis Outlook and Forecast for Yukon Chinook Salmon Timing was released on July 25, 2016. It indicates that the 2016 timing forecast was very close to the actual timing. Chinook began to arrive at the end of May. The run developed as expected with the middle of the migration occurring June 19. See the full report for more details.

The forecast of the dates of percentiles of the Chinook salmon run for the Yukon River delta has been posted by AOOS each year since the 2012 season, along with a qualitative assessment, or outlook, of the timing for each season in the context of the historical spring weather conditions. Last year’s forecast season (2015) was highly successful. Due to the warm water conditions in the Gulf of Alaska and Bering Sea (the Blob) the conventional wisdom was calling for an early run on the delta, similar to the very early run of 2014. Nonetheless the timing forecast model predicted a slightly late run in 2015, and the companion timing outlook called for an average to late run, in contradiction of conventional wisdom. Since 2015 turned out to be a late run, the outlook and forecast helped fishery managers put the incoming test fishing catch information in its proper context. See the full record of the environmental time series and timing model for the 2015 season.

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 2016. The outlook and its associated forecast are based on the historical fish and environmental variables for which the 2016 data are given below. Contained on this page will be (1) the modeled and estimated cumulative daily percentage of the 2016 Chinook salmon run, (2) the cumulative CPUE of the delta test fisheries, as reported daily in 2016 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 2016 outlook and forecast model. As data on the 2016 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, 2016. 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 2016 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 earliest run (green line at left) was observed in 1996, and the latest run (orange line far right) was observed in 2012. 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)

Corrected May Mean Sea Surface Temperature: -0.57 degrees Celcius

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

WARNING: On May 5, 2016, the current DMSP satellite (F17) experienced a problem with the primary channel used to derive sea ice concentrations and NSIDC halted production of the Near-Real-Time DMSP SSMIS Daily Polar Gridded Sea Ice Concentrations in use by this site. NSIDC is still working on the calibration of the replacement (F18) data, which is being shown on the graph below after May 5th. The lack of calibrated data may impact the accuracy of this year’s forecast.

Corrected Mean Ice Cover, March 20 – May 31: 41.55%

Winds measured at Emmonak Airport (mph)