Cruise details and biological information from the Pacific ocean perch monitoring survey, R/V W.E. RICKER, June 19-30, 1993 / by B.M. Leaman, A.M. Cornthwaite, and R.D. Stanley. : Fs97-4/2388E-PDF

"The results of the first monitoring cruise to the experimental fishing area off Langara Island (Langara Spit) are presented. The survey occurred three years after a seven year experimental period of unrestricted fishing on rockfish (Sebastes spp.) stocks. Forty-two bottom trawl hauls, deployed in a stratified random design, were used to collect biological samples and catch rate data. Length, age, and maturity data for all commercial species of rockfish in the survey area are presented by subarea. Age composition of the S. alutus stock showed prominent modes representing the 1984, 1980, and 1976 cohorts. Comparison of Pacific ocean perch age composition with that of other areas subject to quota management during the same period shows the strong 1976 cohort reduced to subordinate status in the experimental area, while it remains the dominant cohort in quota-managed areas. Although the emphasis of the survey was on biological data collection, biomass estimates and bootstrapped 95% confidence intervals were calculated for major rockfish species. The rockfish biomass in the area (9824 t ± 32%) was dominated by Pacific ocean perch (S. alutus) which accounted for over 62% of the biomass (6143 t ± 47%), with S. brevispinis, S. reedi, and S. zacentrus contributing from 6-12% of the biomass"--Abstract, page iii.

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