Proposed methodology for the assessment of the exploratory fishery for Dissostichus spp. on BANZARE Bank (Division 58.4.3b)

In 2006 the CCAMLR scientific committee noted several features of exploratory Dissostichus fisheries in the southern Indian Ocean (58.4) which gave cause for concern as to the status of the resource in this area, and the lack of a scientific basis for setting catch limits in these areas (SC-CAMLR XXV, paragraphs 4.184-4.192).
In its management advice for this and other exploratory fisheries, the Scientific Committee requested urgent consideration by Members on of methods for collecting of data and of assessing these stocks. We outline a methodology to assess the BANZARE fishery including:
• Identification of grounds through analysis of spatial pattern in catch and effort;
• Construction of standardised CPUE series for each ground;
• DeLury/Leslie analysis of standardised CPUE of Dissostichus and major bycatch groups to provide initial estimates of biomass and rates of depletion in each ground until such time as they can be improved; and
• Estimation of the proportion of the stock which can be harvested (?) to satisfy the CCAMLR decision rules.
• Analysis of relative catch rates of bycatch groups and target species
The input data for this assessment is the C2 catch and effort data held by CCAMLR for the fishery in this Division since it began in 2003/04.
The results presented in this paper indicate that this methodology will produce an improved understanding of the trends in this fishery and greatly assist in developing management advice for the stocks of Dissostichus and major bycatch species on BANZARE Bank.
We welcome recommendations from WG-SAM as to the most productive way forward to an assessment for this Division to be considered at CCAMLR XXVI.