Identification and Assessment of Fishing Grounds Based on Fishing Opportunity in the Antarctic Krill Fishery (Euphausia superba Dana, 1850)

The Antarctic krill (Euphausia superba) fishery is concentrated on the main islands, shelf and continental slope. The changing climate has allowed fishing vessels to access new fishing grounds. In this context, spatial patterns in krill distribution largely determine fishing opportunities and tactics. A fishing opportunity is an area selected by a vessel's skipper that may be recurrent, sporadic or unusual. To distinguish between recurrent, sporadic or unusual fishing opportunities in the krill fishery, fishing logbooks covering 2017-2024 were analyzed. Fishing operations were conducted in subareas 48.1 to 48.3, we compared the position of individual fishing hauls (Euclidean distance) applying a hierarchical agglomerative clustering technique. The clusters obtained represent the spatial distribution of fishing opportunities (n = 27), which were unusually visited (<10 hauls, <3 years), sporadic (10 < 49 hauls, spanning half of the time series) and recurrent (>50 hauls, covering the most years). Recurrent fishing opportunities (n = 7, A-G) are distributed in statistical subarea 48.1 (Bransfield Sound, n = 3) and 48.2 (South Orkney Islands, n = 4). A multivariate correspondence analysis was carried out, showing the specific relationship between fishing opportunities with bycatch, water temperature, krill population structure and CPUE. While the proportion of gravid females and juveniles identifies areas of importance for krill reproduction and recruitment, the trend of CPUE allows us to characterize fishing opportunities and identify local depletion. The proportion of gravid females and juveniles evidenced probable breeding and recruitment areas (South Orkney Islands and Bransfield Strait, respectively). While the trend of catch per unit effort allows us to identify local depletion, in two recurrent fishing opportunities.