NOAA Fisheries News Releases
June 8, 2012
Julie Speegle, 907-586-7032 w., 907-321-7032 c.
Scientists collaborate to predict seasonís first king salmon on the Yukon River
When are the salmon coming? Thatís the question people in communities all along the Yukon River are asking this month, as they gear up for another season of fishing.
The timing of the yearís first run of Chinook (king) salmon can vary by as much as 20 days, depending on spring conditions. Over the past 50 years the first pulse of Chinook on the Yukon delta has occurred between June 6 and 26.
In years when the first pulse comes late, it is reasonable for fishery managers to conclude that the run is very weak, perhaps so weak that fishing needs to be slowed or stopped altogether. At the beginning of the fishing season, 20 days can be a long time to wait to find out when the fish are actually coming and if there are enough of them to harvest.
Traditional knowledge on the Yukon holds that spring weather conditions, including ice, temperatures, and wind determine when the fish enter the river, but each spring brings a different combination of conditions, so predicting the arrival of the first run can be tricky.
A team of researchers from NOAA Fisheries and the Alaska Department of Fish and Game, with the support of the Alaska Ocean Observing System, have identified a combination of spring conditions that is closely related to the timing of Chinook salmon on the Yukon delta:
- Percentage of spring ice cover between St. Lawrence Island and the Yukon delta
- April air temperatures in Nome
- Marine surface temperatures just offshore of the Yukon delta in May
Using data from these spring conditions, researchers have predicted the timing of the first Yukon River Chinook run for the past two years within three days of the actual start of each run.
The forecast for 2012 is for a late run similar to that experienced in the cool spring of 2010, the first year of the pre-season forecast, when the first few kings were caught in test nets on June 3, but the first large pulse did not hit the delta until June 16. As of June 6, 2012 no kings had been caught in the test nets, so this yearís run may be a little later than in 2010.
For the latest run timing information and more information on the forecast visit the AOOS web site at: http://www.aoos.org/yukon-chinook-forecasting-data-page/
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