Density estimation of Antarctic krill (Euphausia superba) around South Shetland Island and Elephant Island (Subarea 48.1) using two frequencies with 38 and 120 kHz

The density of Antarctic krill swarm inhabiting the Subarea 48.1, which includes the Elephant Island peripheries and the west and north of the South Shetland Island, was estimated using an acoustics survey. Acoustic data were collected using two frequencies with 38 and 120 kHz from March 8 to 15 in 2019. Krill were collected by the commercial midwater trawl fishing vessel. The data were processed and analyzed by CCAMLR standard protocols using swarm integration (SHAPES module within that software for swarm identification) and interval method based on distribution of (a) total krill AT and (b) each transects krill AT. The weighted krill density was estimated to be 4.27 g/m² (CV=43.42%) applying (a) total krill AT and 4.17 g/m² (CV=44.23%) applying (b) each transects krill AT using swarm integration method and 3.70 g/m² (CV=43.83%) applying (a) total krill AT and 3.49 g/m² (CV=43.60%) applying (b) each transects krill AT using interval method, respectively.