Unusual occurrence of a mixed-pod of false killer whales (Pseudorca crassidens) and common bottlenose dolphins (Tursiops truncatus) in the Beagle Channel (Argentina)

SAN MARTÍN ANALÍA A.; PASO VIOLA M. NATALIA; TARTAGLIA GAMARRA M. BELÉN; ORDOÑEZ CONSTANZA; ASPLANATO NATALIA; TORRES MONICA; DELLABIANCA AGUSTINA; BECKER YAMILA A; BERGAGNA LUCÍA; DELLABIANCA NATALIA; RICCIALDELLI LUCIANA

POLAR BIOLOGY

SPRINGER

Lugar: Berlin; Año: 2023 vol. 46 p. 589 - 595

0722-4060

Nonaggressivemixed-species groups of false killer whales (Pseudorca crassidens) and common bottlenose dolphins (Tursiops truncatus) are frequentlyobserved at many locations around the world, but they are not commonly seen inTierra del Fuego. This work reports the first sighting of a mixed-pod of falsekiller whales and common bottlenose dolphins and its live mass-stranding event inthe inner Beagle Channel, Tierra del Fuego (Argentina) in February 2022. Themixed-pod was confirmed to be comprised of ~50 false killer whales (includingcalves) and four common bottlenose dolphins, but only false killer whales wereinvolved in the mass-stranding event which occurred at the inner and westernsector of Ushuaia Bay next to urban settings. The interaction of natural andhuman-related factors appears to have caused the mass-stranding in this case; however,it is still unknown why the pod was inside the channel. Although all animalswere rescued alive, two animals were found dead days after the event. These sightings and stranding may be consideredextralimital records for Tursiopstruncatus and add new records intheir southernmost (summer) range for Pseudorca crassidens. The handling ofthe situation during these events also suggest that a better marine mammal-stranding network response program is neededin this southern region.