Southern right whale (Eubalaena australis) surveys in the Falkland Islands (Malvinas) during winter 2019 and 2020: preliminary results
Caroline R. Weir
A winter occurrence of southern right whales(SRW; Eubalaena australis) wasfirst documented along the north-east coast of the Falkland Islands (Malvinas; south-west Atlantic) in2017. Targeted boat surveys were carried out throughout the winters of 2019 and 2020, incorporating data collection on SRW distribution, photo-identification and tissue sampling. Additionally, a two-year baleen whale acoustic monitoring programme was carried out. A total of 2,742.3 km of boat survey effort was completed, recording 160 on-effort sightings of SRWs, and an additional 35 off-effort sightings. The encounterrate (sightings/km effort) was highest between June and August, peakingduring July. Sightings comprised 1–17 animals, and included adults and juveniles; no calves were observed. The proportion of sightings where surface active and social behaviour dominated, comprised22% of sightings ofsingle animals, 39.5% for pairs, and 78.8% for groups of ≥3 animals.Over 36,000 images were taken during the boat surveys. Analysis of ~10,300 imagesresultedin 67 individuals being catalogued. The partially-analyseddataset includes one recapture from 2017, and one within-year recapture in 2019. A total of 95 tissue samples (including some duplicates) were acquired via biopsy sampling, and an additional sample from a stranding; the samples are undergoing genetic and isotope analysis. SRW calls, including upsweeps, variable tonal calls, and series of gunshot sounds, were evident in the acoustic recordings; full analysis of the dataset should better clarify SRW temporal occurrence. The extensive work in 2019 and 2020 supports a significant and persistent SRW occurrence along the north-east coast of the Falklands (Malvinas) during winter. The region appears to be used both as an area for social interactions among juveniles and adults, and for courtship andmating. The importance of the Falkland Islands (Malvinas) as a south-west Atlantic wintering ground merits recognition in regionalconservation management plans for the species.