WAMI-01

Commercial trawl fisheries in the modern era started within the Heard Island EEZ in 1997. This paper summarises the fishing activities to date and collates the information on the biology of the species gathered from the fishery and from a series of fishery-independent surveys conducted between 1990 and 2000. Icefish abundance varies widely between years and the fishery is dependent on Read More
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In 2000, CCAMLR asked the Working Group on Fish Stock Assessment (WG-FSA), whether trawl surveys are the most reliable and appropriate method to survey stocks of mackerel icefish (Champsocephalus gunnari). Recent acoustic data from the South Atlantic suggested that mackerel icefish may not always be distributed closely on the sea floor during the day as conventional wisdom would have it, but Read More
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The paper contains comparative analysis of mackerel icefish and krill vertical and horizontal distribution based on acoustic measurements and results of bottom and pelagic trawling sampling. Significance of studying the krill and mackerel icefish interaction for understanding the regularity of mackerel icefish distribution is shown.

C.gunnari form no aggregations during wintering period and inhabit places that are inaccessible for fishing. Conduction of census surveys during this period is pointless. In spring, during feeding period, they form aggregations near bottom thus being available for harvesting just at the beginning of this period (September). Data on stock assessment collected during accounting survey are good Read More
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Stocks of the mackerel icefish Champsocephalus gunnari in the Southern Scotia arc region of the Southern Ocean (CCAMLR Subarea 48.1 & 48.2) have several different biological characteristics than stocks in the Northern Scotia Arc. The history of commercial C. gunnari exploitation in the Southern Scotia Arc was short lived and intense, and led to the collapse of the stocks. Stocks in this Read More
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The depth distribution of C. gunnari was investigated with data from 9 groundfish surveys between 1986 and 2000 using data from representative, randomly located hauls. The data set for South Georgia (Subarea 48.3) but excluding Shag Rocks comprised between 58 and 61 bottom trawls in each of 8 depth strata with mean depths of 112, 137, 165, 185, 208, 230, 257 and 308 m. Fish were divided into Read More
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The applicability of various methods to assess icefish natural mortality is analysed. On the basis of the conclusions made the parameters of Bertalanffy’s growth equation and natural mortality rate are estimated.