In May 2025, an acoustic survey was conducted in the northern half of the Gerlache Strait to estimate the density of Antarctic krill (Euphausia superba). Utilizing the supply vessel Antarctic Provider as the data collection platform, the survey recorded a highly localized distribution of krill in the bays and canyons along the eastern coastline of the Gerlache Strait. Krill density was the highest in Wilhelmina Bay, Charlotte Bay, and Bancroft Bay, contrasting with the absence of krill along the center of the Gerlache Strait and Hughes Bay. The average krill density in the stratum was 197.02 (CI: 133.56 - 289.95) g m-2. This density is comparable to the high densities found in the hot spot north of the South Orkney Islands during annual summer surveys.
Although numerous acoustic surveys have been conducted in Subarea 48.1's, especially the Bransfield Strait and areas around the South Shetland Islands have often been in focus, few have covered the comparatively narrow Gerlache Strait. However, extensive surveys by Chinese fishing vessels in 2023 and 2024 included transects inside Gerlache Strait, revealing large krill aggregations in May, with similar distributions to those found in this study. In contrast, their February 2024 survey recorded low krill densities in these bays, with krill concentrated primarily in Hughes Bay.
This study also demonstrates the feasibility of utilizing commercial vessels for acoustic data collection without the need for specialized onboard expertise. With modern satellite communication technology, it is possible to transmit relatively large data files for further processing onshore. This enables the calculation of krill biomass in a given area, ensuring that accurate and timely data can be obtained even when specialized personnel are not present on the vessel.