Stock assessments for British Columbia herring management units in 1981 and forecasts of the potential catch in 1982 / by A.S. Hourston.: Fs97-4/1631E-PDF

"The abundance of the 1981 adult herring run in British Columbia waters was assessed at 328,000 t. This was up 46,000 t (16%) from 1980 and close to average for the period 1971-80 (334,000 t). Runs to the Gulf of Georgia and Queen Charlotte Islands division were up 58,000 t and 10,000 t respectively in 1981 while runs to the other 4 divisions were similar in abundance to those in 1980. However, there are some indications that the run to the Gulf of Georgia may have been overestimated in 1981. Fisheries took only 11% of the runs harvested during the 1980-81 season, but over 30% of the run was harvested in 3 of the 35 management units. The forecast for the 1981 run was 117 lower than the actual run. Forecasts for the Queen Charlotte Islands and Gulf of Georgia divisions were low by 39% and 43%, respectively, while the forecast for the West Coast of Vancouver Island division was high by 27%. Forecasts for the other 3 divisions were within 12% of the actual runs. Major discrepancies between forecasts and runs were attributed to weaknesses in the data base for 5 major management units. Forecasts of the 1981 runs to most of the 30 remaining management units were reasonably close to the runs as subsequently estimated. The 1982 run is forecast at 314,000 t with average recruitment: poor recruitment would reduce the forecast to 242,000 t and good recruitment increase it to 428,000 t. Forecasts by division and management unit are close to abundance levels for 1981. Average recruitment would provide a potential catch of 135,000 t under a moderate management policy and 80,000 t under conservative management. Other constraints encountered during recent fisheries would reduce these catch levels to 65,000 t and 42,000 t, respectively"--Abstract, page iii.

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