Whales return to the epicentre of whaling? Preliminary results from the 2020 cetacean survey at South Georgia (Islas Georgias del Sur)
Kennedy, Carroll, Baker, Bassoi, Buss, Collins, Calderan, Ensor, Fielding, Leaper, MacDonald, Olson, Cheeseman, Groch, Hall, Kelly, Miller, Moore, Rowntree, Stowasser, Trathan, Valenzuela, Vermeulen, Zerbini, Jackson
International Whaling Commission
Over 170,000 whales were killed in the sub-Antarctic waters of South Georgia (Islas Georgias del Sur, SG, South Atlantic) from 1904 to 1965. In recent decades, whales are regular summer visitors, with the southern right whale (Eubalaena australis) and humpback whale (Megaptera novaeangliea) most commonly reported. A 23-day cetacean survey was conducted in SG waters during January/February 2020, using directional acoustics and visual surveys to localise whales, and collecting skin biopsies, faecal samples, photo-identifications, and blow samples for microbiome analysis. The survey focussed on southern right whales (SRW) and also collected sightings, photo-identifications and skin biopsies from other species. A total of 1,147 nautical miles of visual survey effort was conducted, and 4 prey-field surveys (totalling 34 nm) using active acoustics. In total, cetaceans were encountered 540 times (521 encounters in SG waters), including southern right whales (SRW, 10 encounters of 11 individuals), humpback whales (409 encounters, ~790 individuals) and blue whales (Balaenoptera musculus, 38 encounters, ~58 individuals). Two SRW were satellite tagged and their movements subsequently tracked. Photo-identifications and biopsies were collected from southern right (11 and 7 respectively), humpback (48 and 17 respectively) and blue whales (25 and 9 respectively). Aerial imagery was collected via Unmanned Aerial Vehicles (UAVs) during four SRW, with three blow samples also collected. Additionally, one faecal sample was collected from one SRW. Overall, this expedition yielded an unprecedented number of sightings of both blue and humpback whales, suggesting that the waters of SG are once again becoming an important summer feeding ground for both species.