Research Document - 2001/138

Pacific Ocean Perch Assessment for the West Coast of Canada in 2001

By Schnute, J., Haigh, R., Krishka, B., Starr, P.

Abstract

Pacific ocean perch (Sebastes alutus, commonly called POP) dominate the rockfish catch in Canada's Pacific groundfish trawl fishery. The species belongs to a larger community of slope rockfish species that inhabit the sloping walls of marine canyons along the coast of British Columbia. This report compiles the scientific data currently available for POP and evaluates its relevance to setting quotas. Following the rationale in the 1997 assessment, we present an updated catch-age analysis for the Goose Island Gully (GIG) stock and extend these results to the rest of the coast. Our analyses take account of spatial distributions and other biological features investigated in slope rockfish stock assessments since 1998.

Our catch-age analysis indicates that the GIG stock currently experiences low recruitment at age 7, probably associated with an ocean climate regime starting in 1988. We urge caution in setting quotas, so that adequate biomass remains for the future when productivity improves. Our coastwide analysis suggests that the current quota distributions among management areas match available biomass levels fairly well, although we find possible opportunities for quota redistribution.

Our models contain many debatable elements, but we are constrained by available data. We have relatively few research surveys, and most data come from the fishery itself. We use graphics and intuitive discussion to engage stakeholders in thinking actively about the current state of our knowledge. Final decisions depend on human judgement, given the facts available. We suggest various options for setting quotas, including maintenance of the status quo.

We also highlight opportunities for future data collection, standardization, and quality control. In particular, we recommend fishery-independent surveys to obtain age distributions that include young fish aged 3-5. Data from such surveys would provide leading indicators of recruitment to the fishery at age 7.

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