Dynamics of the Antarctic krill resource in a fishery hotspot in the Bransfield Strait

The Antarctic krill fishery has evolved to operate mainly in some predictable areas in recent years, and knowledge on the inter-annual variability and the potential intra-annual seasonal trend of the krill biomass in these fishery hotspots is critical to understand the three-way interactions between krill resources, krill-dependent predators and the krill fishery. Based on the acoustic data collected by the Chinese krill fishing vessels from the 2012/2013 to 2021/2022 fishing seasons, a perennial hotspot of krill resource in the Bransfield Strait (BS) was identified using the Bootstrap statistical method. The results suggested a seasonal dynamic nature of the krill biomass in the hotspot, marked by significant monthly increase from the end of austral summer (December to March) to autumn (April and May). The local scale krill biomass in the hotspot during autumn could even be several folders of those estimates from typical acoustic transect survey for the entire BS stratum in summer seasons. The Catch per Unit Effort (CPUE) data has also corroborated the monthly variability trends observed through acoustic data assessments. This research provides valuable information for the development of spatial-temporal management of krill fishery, and potential direction of future research is also discussed.