Research Document - 2004/027

Bocaccio update

By Stanley, R.D., Starr, P., Olsen, N.

Abstract

The present paper updates the available information on the stock status of bocaccio (Sebastes paucispinis) in BC waters. It updates information on catch, CPUE and survey indices where appropriate, from the previous PSARC document (Stanley et al. 2001). In addition, given the importance of the results from the NMFS triennial and West Coast Vancouver Island shrimp surveys with respect to stock status, it provides more comprehensive analyses of these data to communicate more accurately the degree of certainty around the point estimates and the inference of declines in abundance. The document notes the strong evidence of a significant decline in relative abundance from the early 1980's off the southwest coast of BC but also recent stability in the same indices and provides two management directions for consideration. Considering that the only remedial action available for managers is to control catches, Option #1 endorses capping catches at current levels provided existing indices do not decline. Option #1 might also be adopted as an interim measure until a more complex catch reduction strategy can be implemented. Option #2 endorses reducing catch to an arbitrary target level. A significant reduction in catch may be possible through implementation of a voluntary avoidance program, possibly in conjunction with regulatory disincentives to catch bocaccio. However, the document emphasizes that the available assessment information is not adequate to predict how much a given reduction in catch will affect the population and therefore not adequate to provide specific advice on the amount of reduction required. The choice between options is dependent on the degree to which the southern BC area is assumed to reflect all BC waters, and whether the higher relative abundance recorded in the early 1980's is indicative of the long term average abundance or reflects peak levels resulting from a period of good recruitment. This uncertainty in the interpretation of the available abundance indices, along with their low precision, means that it is presently not feasible to reliably estimate stock status for bocaccio in BC waters.

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