Second largest Bristol Bay forecast ever released by the University of Washington's Fisheries Research Institute.
DILLINGHAM: According to the experts at the University of Washington's Fisheries Research Institute, next summer's total run of sockeye to Bristol Bay will top 49 million. FRI's forecast comes days after the Alaska Department of Fish and Game released it's total run prediction of 53.9 million.
Either number represents one of the biggest forecasts on record.
"At 49.49 million sockeye, the 2015 Bristol Bay forecast is the second largest ever released by UW-FRI. Only 1995 had a a larger forecast at 53.32 million sockeye," writes FRI.
They say that only six runs exceeding or equal to 49.5 million sockeye have been recorded since 1960 (1965, 1980, 1990, 1993, 1994, 1995).
Here's how FRI puts their forecast together, in their words:
Historical catch and escapement data collected by the Alaska Department of Fish and Game from 1963 to present were used to generate this forecast. Pre-season forecasts generated between 2004 and 2011 used a shorter time series of this data (1978-‐2011) to make predictions because 1978 is commonly recognized as a point when long-term trends in productivity of the North Pacific and Bristol Bay sockeye stocks showed a dramatic increase.
However, we believe large scale shifts in climate patterns have occurred, and that sockeye production in some Bristol Bay systems can be more accurately forecasted by incorporating data from a longer time series that includes a greater number of “cool phase” Pacific Decadal Oscillation (PDO) years. All 2015 forecasts (36 individual forecast, nine rivers by four age groups) are based on prior returns of “siblings” or younger ocean age classes from the same brood year.
However, rather than simply choosing the best sibling relationship for each age and river, we use a technique that weights the forecasts for all potential predictor sibling relationships according to how well they have performed in the past. While the best sibling relationship carries the most weight in our forecast, retrospective analysis indicates that there is useful information conveyed by other models (i.e. sibling models that include alternative age classes and combinations thereof). In some years for some river systems, the best model does not necessarily perform well, and incorporating other models improves forecast accuracy.