| Summary: | Progress Code: completed This metadata record describes at-sea seabird observation dataset collected during the 2021 TEMPO (Trends in Euphausiids off Mawson, Predators, and Oceanography) voyage onboard the RV Investigator (see Kelly et al. 2021 for more details on the voyage). 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 aim of the survey was also to improve our understanding on the connectivity of the krill population, and overlap between krill and predators. 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. Comprehensive oceanographic (CTDs, XBTs, Argo 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. Two seabird observers undertook observations from: 1) an enclosed observation deck above the bridge of the RV Investigator (approx. eye height of 24.3m); 2) on the observation deck 05 with the cetacean observers (approx. eye height of 18.4m); 3) and astern on the same level as the observation deck. Observing was undertaken during daylight hours, and during fair-excellent sighting conditions. Formal observing for seabirds was suspended when the vessel stopped/slowed for other sampling operations. During searching effort, one seabird observer scanned for seabirds and the other logged ...
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