A modern approach to catch-age analysis for Hecate Strait rock sole (Pleuronectes bilineatus)

We analyse catch-age data for Hecate Strait rock sole (Pleuronectes bilineatus) over the 1945–1995 period. We employ a stochastic state-space model to assess uncertainty in stock abundance and recruitment trends. Rock sole biomass appears to have increased substantially since 1945. However, the apparent increase in biomass may be an artifact of inconsistencies in the age proportion data. Broad confidence intervals for model estimates of spawning stock biomass and corresponding age-4 recruits illustrate the uncertainty in the stock-recruitment relationship. This uncertainty must be acknowledged when results from catch-age analysis are translated into fishery yields. Thus, the tools we demonstrate here provide one step in implementing the precautionary approach to fish stock assessment.