TEMPO (Trends in Euphausiids off Mawson, Predators, and Oceanography) - scientific voyage of the RV Investigator, 2021

This is a parent metadata entry for data collected during the 2021 TEMPO (Trends in Euphausiids off Mawson, Predators, and Oceanography) multidisciplinary voyage onboard the RV Investigator. The primary goal of TEMPO was to collect data to estimate krill biomass with a view to update the precautionary catch limit for krill in CCAMLR’s Division 58.4.2-East. The TEMPO voyage ran from February to March 2021. The survey consisted of six major acoustic line-transects to estimate krill biomass and to observe swarm behaviour across ecological and density gradients within the survey area south of 62°S between 55° and 80° E, and a single fine-scale krill box acoustic survey off the Mawson coast. The voyage successfully estimated mean areal biomass for the region. Along with acoustic survey, net sampling was also conducted, a swarm study system, deep-sea cameras and light traps were deployed, in addition to Krill Observational Moorings for Benthic Investigation (KOMBI) being deployed on the seafloor that will record the behaviour of krill throughout a full year to understand the dynamics and use of habitat in the surface layer as well as at seafloor. Comprehensive oceanographic (CTDS, XBTs ARGSO floats) and biological (plankton) sampling were also conducted to understand the habitat environment of krill and its predators. Predator observation was undertaken throughout the voyage to improve our understanding on the connectivity of the krill population, and overlap of distribution between krill and predators. The information gathered from the contributes to the design of tractable and sustainable long-term monitoring plan and to evaluate spatial management of the krill fishery.