Browsing by Subject "rock lobster resource"
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- ItemRestrictedThe 2004 age-structured production model assessments and projections for the South Coast rock lobster resource(2004) Johnston, Susan J; Butterworth, Doug SThe 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
- ItemOpen AccessImplications to existing OMP of the 2010 updated assessments of the south coast rock lobster resource(2010) Johnston, Susan J; Butterworth, Doug SJohnston and Butterworth (2008) reported expected results for the final OMP 2008 for the South Coast Rock Lobster fishery. This OMP 1. has a 5% maximum TAC change constraint, and 2. has a median anticipated sp B (2025/2006) of 1.20 under operating Model 3 (MARAM TVS). Recently, a programming glitch in the operating models has been discovered. The result of correcting this glitch is reported in Johnston and Butterworth (2010). Here we compare the OMP 2008 expected performance statistics using the original 2008 operating models with those produced using the corrected operating models conditioned on the data available at that time. The current “OMP 2008” was tuned using the original 2008 Model 3 operating model.
- ItemOpen AccessRe-tuning of OMP-2008 using updated 2010 operating models for the South Coast rock lobster resource to provide OMP-2010(2010) Johnston, Susan J; Butterworth, Doug SThis document provides detailed specifications for population projections under future possible catch series, and details of the OMP. Based on updated operating models OMP-2008 is re-tuned to attain the same median recovery target of a 20% increase in spawning biomass from 2006 to 2025 as agreed two years previously. Results are not greatly changed, with new projections of spawning biomass showing a little greater uncertainty under the resultant OMP-2010 than was the case previously.