Abstract: The feeding behaviour of short-beaked common dolphins (Delphinus delphis) was observed over a 3-year period, off the east coast of New Zealand's North Island. Six prey species were identified: jack mackerel (Trachurus novaezelandiae), kahawai (Arripis trutta), yellow-eyed mullet (Aldrichetta forsteri), flying fish (Cypselurus lineatus), parore (Girella tricuspidata), and garfish (Hyporamphus ihi). When feeding, common dolphins frequently were associated with Australasian gannets (Morus serrator) and on rare occasions with minke (Balaenoptera acutorostrata), sei (B. borealis), and Bryde's whales (B. edeni). Several distinct feeding strategies were identified, and are described in detail. Feeding methods employed by individual dolphins were high-speed pursuits, fish-whacking, and kerplunking. Coordinated feeding strategies included carouseling, line-abreast, and wall-formation. Temporary division of labour was observed during some coordinated feeding bouts. Bubble-blowing was used to startle herded fish. An episode of bubble-blowing by a Bryde's whale was also observed. Many of the feeding strategies employed by common dolphins show a high degree of similarity to those reported for bottlenose dolphins (Tursiops truncatus), killer whales (Orcinus orca), and dusky dolphins (Lagenorhynchus obscurus). The variety of feeding strategies indicates a high level of behavioural plasticity in common dolphins.
Key Words: SHORT-BEAKED COMMON DOLPHIN; DELPHINUS DELPHIS; FEEDING; BEHAVIOUR; PREY; FEEDING STRATEGIES; CAROUSELING; FISH WHACKING; KERPLUNKING; BUBBLE-BLOWING; AUSTRALASIAN GANNET; MORUS SERRATOR; BRYDE'S WHALE; BALAENOPTERA EDENI; NEW ZEALAND
Document Type: Research article