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SC/69B/SAN/01Rev1
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Resource ID
22091
Access
Open
Document Number
SC/69B/SAN/01Rev1
Full Title
WINTER CETACEAN SURVEYS (APRIL ? SEPTEMBER 2022 AND 2023) AROUND THE SUB-ANTARCTIC ISLAND AT 54ø15?S 36ø45?W
Author
Russell Leaper, Martin Collins, Susannah Calderan, Cecilia Liszka, Paula Olson, Conor Ryan and Jennifer Jackson
Authors Summary
[To come]
Publisher
IWC
Publication Year
2024
Abstract
Visual and acoustic surveys of baleen whales in waters around the sub-Antarctic island at 54ø15?S 36ø45?W were carried out between April and September in 2022 and 2023 as part of a two-year project investigating the abundance and density of krill and krill-feeding predators around the island in the austral winter. Humpback whales (Megaptera novaeangliae) were the most frequently seen species in all periods, followed by southern right whales (Eubalaena australis) and fin whales (Balaenoptera physalus). Blue (B. musculus intermedia), sperm (Physeter macrocephalus) and killer whales (Orcinus orca) were occasionally encountered. Acoustic surveys using DiFAR sonobuoys identified many humpback whale vocalisations in July 2022 but not in September 2023 despite sonobuoys being deployed in areas close to humpback whales. This suggests possible seasonal changes in vocalisation behaviour. Analyses of this work are ongoing in order to relate observed distributions of whales to krill occurrence and density.