Preliminary assessment of Dissostichus eleginoides on the Heard Island Plateau (Division 58.5.2) based on a survey in May 2002

A survey of Patagonian toothfish, Dissostichus eleginoides, was undertaken in Division 58.5.2 in the vicinity of Heard Island in May 2002 to provide the information for an assessment of long-term annual yield in the 2002/2003 CCAMLR season and beyond. This paper provides a preliminary assessment of yield using the assessment methods of CCAMLR, a summary of which is presented here. The estimate of biomass of juvenile Patagonian toothfish in the vicinity of Heard Island was similar to the results for 2001. The pooled length-density distribution for the 2002 survey shows that the younger year classes (ages 2 and 3) are likely to be much weaker than the current juvenile year classes (ages 4 to 8) in the survey area. The analysis also shows that larger fish seem to have left the survey area. The latest survey was used to update the recruitment series used in the assessment and resulted in estimates of recruitment being increased for some recent years. An assessment of the trend in illegal catches is expected to be undertaken at the Working Group on Fish Stock Assessment, including projections for the remainder of the season. Thus, a revision of the assessment provided here is expected to be needed following that work. The results indicate that the long-term annual yield based on the revised recruitment estimates is expected to be around 2 910 tonnes for 2002/2003 CCAMLR season. This result is slightly greater than for the 2001/02 season because of the revision in the recruitment series. The time-trend in spawning biomass, fishing mortality and recruitments arising from this assessment are presented.