Preliminary results of length distribution of Antarctic krill (Euphausia superba) around the Antarctic Peninsula during winter 2023 and summer 2024

Chinese krill fishing vessels conducted surveys in Subarea 48.1 during May 2023 and February 2024, covering the Gerlache Strait (GS), Bransfield Strait (BS), Elephant Island (EI), Joinville Island (JI), and the west side of the South Shetland Islands (SSIW). This study compared the length distribution of krill across these regions during winter 2023 and summer 2024 using samples collected via Rectangular Midwater Trawl. The length distribution of Antarctic krill exhibits consistent patterns across BS and JI throughout both winter and summer seasons. In winter 2023, krill lengths were predominantly between 35-45mm. By summer 2024, both regions showed a shift with more krill in the 25-30mm range. SSIW and EI in summer 2024 displayed a peak between 40-50mm, whereas SSIW in winter 2023 had smaller peaks around 20mm. Spatially, krill sizes vary seasonally around the Antarctic Peninsula: smaller krill dominate BS during winter, while larger individuals are more prevalent in the coastal areas of GS and JI. In summer, larger krill are found near the South Shetland Islands and EI, while JI hosts smaller krill. Each region demonstrates distinct seasonal variations in krill length distribution, underscoring the need for further ecological analysis.