UW News

August 12, 1997

Warm, unusually calm weather may be reason Bristol Bay sockeye run was far smaller than expected

News and Information

The return of sockeye salmon to Alaska’s Bristol Bay fell 15 to 20 million fish short of expectations, leading to significant economic and social hardship for fishermen, processors and local communities.

Fewer than 19 million sockeye returned between June 25 and July 20 although pre- season forecasts last fall by the Fisheries Research Institute of the University of Washington and the Alaska Department of Fish and Game estimated that between 34 and 35 million sockeye salmon would return. Even a week before fish arrived in the bay, the Port Moller test fishery indicated that between 35 and 40 million fish could return. Operated by the UW’s Fisheries Research Institute, the test fishery has provided reliable forecasts for the previous 11 years.

Conditions at Port Moller this year were unusually warm and calm, with no fishing days lost to bad weather. There was no indication of unusual distribution or milling of fish at Port Moller.

“We believe the poor return was due to the highly unusual weather, both the warm water temperatures associated with a building El Nino event, and the very calm wind conditions that were totally beyond previous experience,” said Don Rogers, UW research professor.

Rogers said other explanations for the poor return could include mortality of fish between Port Moller and the fishing areas, warm conditions and low river flows leading to poor ocean survival or a change in the distribution of the fish at sea that impeded their return to natal streams. The UW’s Fisheries Research Institute is examining these hypotheses and anticipates releasing a preliminary report in October.

Forecasts of runs are based each year on parental spawning stocks, smolt migrations counts, return of younger year classes and historical ocean survival rates. The Port Moller test fishery is operated by the UW’s Fisheries Research Institute and has proven reliable for the past 11 years.


For more information:
Don Rogers, research professor, UW’s Fisheries Research Institute
(907) 842-5380 from Aug. 13 until Sept. 5
(206) 543-7628 in Seattle

Ray Hilborn, associate director of research, UW’s Fisheries Research Institute, a part of the School of Fisheries
Returns to Seattle Aug. 18
(206) 543-4650
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