Some aspects of acoustic- trawl surveys for the mackerel icefish (Champsocephalus gunnari) assessment in the CCAMLR Statistical Subarea 48.3 as fish with a semi-pelagic distribution are discussed.
It is proposed that present-day mackerel icefish survey in Subarea 48.3 would represents complex trawl and acoustic surveys based on synthesis of two equal methods including acoustic method for pelagic biomass assessment and trawl survey method for assessment of icefish demersal biomass. Results of these complex trawl and acoustic surveys will provide adequate data for assessment of the Subarea 48.3 icefish biomass and for the CCAMLR length-based method to derive catch limit advice . The latter becomes relevant in the context of the observed dynamics of fish demersal biomass in recent years with the steady decline in this biomass in the absence of fishing.