Stock assessments for British Columbia herring in 1984 and forecasts of the potential catch in 1985 / by V. Haist, M. Stocker, and J.F. Schweigert. : Fs97-6/1365E-PDF

"Herring stock abundance in British Columbia waters was assessed for 1984, and forecasts were made for 1985 using three methods: (1) escapement method, (2) age-structured model analysis, and (3) surplus production model analysis. The abundance of the 1984 adult herring run in British Columbia waters as assessed by the newly developed escapement method was 148,000 tonnes. This is a decrease of 43,000 t (23%) from the 1983 estimate. The 1985 run is forecast at 211,600 t with average recruitment. The 1985 forecasts for poor and good productivity are 118,300 t and 317,100 t respectively. For the south coast particularly it is anticipated that poor productivity will prevail, due to unfavorable environmental conditions. The forecast from age-structured model analysis for 1985 is 142,000 tonnes. This predicted run size reflects the currently unfavorable conditions. Assuming poor production the surplus production model analysis predicts a run of 544,000 t. These unrealistically high run sizes result from poor model fits obtained for most of the separate stock data sets. The recommended 1985 catch level (20% of the weighted 1985 herring run size) for the B.C. coast is 34,100 t. Under conservative management and other constraints encountered administering fisheries, the catch levels recommended herein may be substantially lower"--Abstract, page iv.

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