Fraser River Sockeye Fisheries and Fisheries Management - Cohen ...

ManagementGroup(IndicatorStock)MAPEError inReturnExplainedbyForecast(R 2 )RegressionSlope(Return :Forecast)RegressionInterceptMG Sizerelative tototal FraserReturnInterpretationRegression analysis: inferences about reliability, precision, andaccuracy relate to long-term trends (1980-2009).MAPE: expected error in any single year’s forecast.Gates 58% 45%Nadina 50% 24%Pitt 53% 0.4%significant)0.77(significant)0.67(notsignificant)0.13(notsignificant)notsignificantnotsignificant1.1%1.6%significant 1.0%forecasts, making forecasts unreliable. Expected Error: expect forecast to overestimate or underestimatereturn by 67% in any given year. Reliability: Relationship between forecast and return is statisticallysignificant, thus forecast is reliable. Precision: Moderate amount of inter-annual variation explained byforecasts (R 2 = 0.45) Accuracy: Slope departs from one and intercept is not significantlydifferent from zero, thus long-term accuracy is good but largeforecasts tend to underestimate returns. Expected Error: expect forecast to overestimate or underestimatereturn by 58% in any given year. Reliability: Relationship between forecast and return is notstatistically significant, thus returns vary at random relative toforecasts, making forecasts unreliable. Expected Error: expect forecast to overestimate or underestimatereturn by 50% in any given year. Reliability: Relationship between forecast and return is notstatistically significant, thus returns vary at random relative toforecasts, making forecasts unreliable. Expected Error: expect forecast to overestimate or underestimatereturn by 53% in any given year.Raft 48% 58% 0.74 not 0.9% Reliability: Relationship between forecast and return is statisticallyH-2