Abstract

During January and February 2016, the K-axis voyage sampled 42 stations across the southern region of the Kerguelen Plateau. The gelatinous tunicate S. thompsoni was a major component of the zooplankton community during this time, with approximately 80, 000 individuals collected during routine trawls. Potential changes in the distribution patterns of S. thompsoni are of increasing research focus, due to the species’ potential to compete with Antarctic krill for resources, and the uncertainty surrounding the effect of high salp scenarios on ecosystem energy flow. As part of quantifying the potential ecosystem input from S. thompsoni, we present K-axis distribution patterns and life history details, as well as a historical comparison of S. thompsoni abundances for the region. We also present an up-to-date nutritional profile of Antarctic krill and salps for the region, and, through methods including stable isotope analysis and gut content analysis, identify areas of increased spatial and diet overlap between Antarctic krill and salps. Results suggest that salp abundances during the K-axis voyage were atypically high for the south Kerguelen Plateau, and that, under high salp abundance scenarios, higher trophic level species may be faced with a food source with