Abstract:
Shepherd’s beaked whale Tasmacetus shepherdi is one of the most poorly known cetaceans, whose diet has created some
speculation given that its dentition differs greatly from that of most other beaked whales that are primarily teuthophagous.
The few stomachs examined previously have given seemingly conflicting dietary information. In this paper the stomach contents
of a freshly stranded adult female on Tristan da Cunha have been examined through identification of trace elements and
genetic analysis of soft parts. At least 13 cephalopod and 8 fish species were identified from beaks and otoliths respectively, but
only undigested fish remains were present in the stomach and identified genetically as Beryx splendens. Reconstituted masses
totaled 8809 g for cephalopods and 17,554 g for fish, with four species (Histioteuthis atlantica, Taningia danae,
Ommastrephes bartrami and Pholidoteuthis ‘A’) comprising 78.6% of the cephalopods and one species (B. splendens) comprising
87.4% of the fish eaten. It is concluded that Tasmacetus may alternately exploit fish and cephalopods, depending on
the time of day and access to seamount or continental slope areas.
