First sighting of a live hourglass dolphin (Lagenorhynchus cruciger) in inland waters of southern Chile

Abstract

The hourglass dolphin (Lagenorhynchus cruciger) has a circumpolar distribution in the Southern Ocean, and although are regularly found south of the Antarctic Polar Front, localized concentrations have also been documented all in pelagic waters around the southern tip of South America, the Falkland Islands, and the South Georgia Islands. On March 8, 2013, a group of three Pealeʼs dolphins and other single individual that was different in color and pattern were sighted in Parry fjord, Tierra del Fuego Island. This atypical individual was identified as an hourglass dolphin, based on the combination of unique characteristics of this species. Although the animal sighted is more likely a vagrant than a migrant to inland waters of southern Chile, it is even more uncertain what biological and/or physical properties were determinants. Seasonal shift in environmental conditions within Drake Passage, thermoregulation, or prey availability have been previously suggested as potential factors in the movements of hourglass dolphin to north of Polar Front.