| Summary: | Progress Code: completed This metadata record describes cetacean line-transect distance sampling dataset collected during the 2021 TEMPO (Trends in Euphausiids off Mawson, Predators, and Oceanography) 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 survey was also designed to improve our understanding on the connectivity of the krill population, and overlap between krill and predators. 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. 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 contributes to the design of tractable and sustainable long-term monitoring plan and to evaluate spatial management of the krill fishery. A team of four dedicated cetacean observers (with contributions from other experienced staff onboard) undertook formal line transect distance sampling when conditions allowed. Two observers were on effort during line transect effort; they were stationed in protective boxes on the forward Deck 05 of the RV Investigator. A data entry person was situated on the bridge; sighting, effort and weather data were logged using PAMGUARD (Pamguard Development Team 2021). The two observers scanned port and starboard, respectively, from abeam (~90° from the ship’s heading) through to around ~10° beyond the trackline on the other side. (i.e., this is single platform sighting data, sensu ...
|
|---|