Aethotaxis mitopteryx, a high-Antarctic fish with benthopelagic mode of life

Abstract

Aethotaxis mitopteryx DeW~tt is one of the lesser known high-Antarctic fish species of the family Nototheniidae. W~thin the last 7 yr close to 90 % of all reported specimens were caught in the Weddell Sea and the Lazarev Sea , with only 5 % of these in pelagic trawls. Average blomass values of ca 0.69 kg 30 min-l, which is 10 times the biomass values attained in the Weddell Sea , suggest the Lazarev Sea at depths between 400 and 800 m, or narrow shelf areas of the eastern Antarctic in general, to be a major distribution area of this species Due to new maximum values reported for length and weight (total length = 48 cm, fresh weigth = 855 g ) currently recorded growth parameters have to be adjusted Adults are characterized by slow growth, high reproductive effort, a benthopelagic mode of life and regular occurrence in the warmer deep water. Due to the high abundance of A. mitopteryx larvae In the Weddell Sea, spawning migrations are likely. Structural and functional features of blood as well as observations from aquaria indicate a sluggish mode of l ~ f e and a limited scope for activity. This and a number of adaptations to life In the pelagial suggest energy requirements to be low.