First confirmed stranding of a fin whale (Balaenoptera physalus) in Tierra del Fuego, Argentina

Abstract

Fin whales (Balaenoptera physalus) can be found worldwide, in oceanic waters, though are rarely found in coastal areas of wide and shallow continental platforms such as those in the western South Atlantic Ocean. Here we report the first confirmed stranding of a B. physalus off the Atlantic coast of Tierra del Fuego (TDF), in July (austral winter) of 2016. In addition, a bibliographic review of the strandings of this species was carried out on the Argentinian coasts and especially on TDF. The animal was fresh when it was found and may have been alive at the moment of the stranding. The specimen was a physically immature female with a total length 15.8 m. No injuries or fishing gear were observed to suggest accidental entanglement or vessel collision. The specimen’s stomachs were empty except for a low-grade infestation with the trematode Ogmogaster antarcticus, but without any associated macroscopic gastric pathology. Although the necropsy was carried out within a few hours of death, we could not make an accurate diagnosis of the cause of death. However, the insufficient fat deposits indicate a bad physical condition and may have contributed to its stranding and subsequent death. This specimen represents the first confirmed stranding of this species in TDF.