Spatio–temporal dynamics of Antarctic krill fishery: identification of fishing hotspots

Antarctic krill is a key species in the Southern Ocean food web and is also the target of the greatest fishery in Antarctic waters. Management of the fishery is based on a precautionary catch limit, representing 0.11 the allowable catch limit for CCAMLR Area 48, and further divided by subarea. Despite that the fishery is operating in the Antarctic Peninsula area since 1980s, the spatial and temporal pattern of the fishery is only described in meso to macro scales (>>10⁴ km²). Here we present a novel analysis to identified fishing grounds, using statistical analysis of hotspots, in this case, fishing hotspots (FH), combined with a temporal analysis to assess persistence of these FHs. Results indicate that the fishery is presenting consistent FH across years, particularly during those years when the precautionary catch limit is reached. These events occur mainly in the centre of the Bransfield Strait and the northern section of the Gerlache Strait, and have a duration of 3 to 5 months. FH identified are small, equivalent to a circle of radius 25 km, and have a high catch density (>10 ton∙km^-2) during years when the catch limit is reached. The analysis show that the krill fishing fleet is concurring to know fishing grounds year after year, where they obtain high catches, and that the catch density (ton∙km^-2) inside the FHs is correlated with the total catch obtained, suggesting its use as an index of krill abundance in an area.