The 2004 age-structured production model assessments and projections for the South Coast rock lobster resource

Abstract

The assessment conducted in 2003 has been routinely extended, taking account of a further year’s catch, CPUE and catch-at-age data. CPUE shows a continuation of the increase that commenced in 1998. Results are generally more optimistic than those for the 2003 assessment; this is shown to be a result of both the new abundance data now available as well as the revision of the historic catch series, with the former having slightly the larger effect. The Reference Case (RC) scenario suggests that a TAC of 360 MT or less would be appropriate to prevent biomass decline in the future. Other scenarios suggest either higher or lower values than this. If the catch-at-age data are down-weighted, then this appropriate level for the TAC is increased to 390 MT. On the other hand, the scenario which assumes the 1995+ recruitment to be equal to the average of the previous 10 years is more pessimistic and suggests an appropriate TAC level of only some 300 MT