Preliminary assessment of mackerel icefish (Champsocephalus gunnari) in the vicinity of Heard Island and McDonald Islands (Division 58.5.2), based on a survey in March–April 2010, including a revised growth model

A survey of mackerel icefish, Champsocephalus gunnari, was undertaken in Division 58.5.2 in the vicinity of Heard Island in March-April 2010 to provide the information for an assessment of short-term annual yield in the 2010/2011 CCAMLR season. This paper provides a preliminary assessment of yield for the area of Division 58.5.2 to the west of 79°20’ E using standard CCAMLR methods. The strong year class detected in the last three years’ surveys is now fully recruited as the 4+ cohort, and dominates the population, however it is assumed this cohort will be unavailable to the fishery in 2010/11. A new 2+ cohort has been detected, and it is expected that the fishery in 2010/11 will focus on this cohort. A new growth model is also estimated which shows an improved fit to observed sizes at age of icefish from recent surveys.