Combined studies on the inner shelf and outer shelf of the Kerguelen islands (1989/90 to 1992/93) provides new informations about Champsocephalus gunnari stock. An inner shelf quaterly programme allows to identify each year, both from the ichthyoplanktonic surveys and bottom trawlings, an annual cohort. Strong differences in abundance of larvae are observed yearly. One cohort seems dominant in the samples along the study. It would explain the previouly observed three years cycle. Spawners have been observed in mass only once during the studied period and are fishes of the 1988 cohort first spawning during the winter 1991/
Abstract:
To determine mackerel icefish Champsocephalus gunnari age, otolith mass was used. The material was collected in July0August 1987 during the joint Soviet-Australian expedition on board R/V PROFESSOR MESYATSEV to heard Island shelf area. The otoliths were weighted with an electric balance to within 0.0001 g. Then the obtained data underwent statistical processing with application of the cluster analysis method. Five age groups were defined. Bertalanffi linear growth equation was calculated:
Lt=41.73 (1-e-0.5149(1+0.05225))
On this basis the size-age key for this season has been estimated.
