Threats to common dolphin
Predators
Killer whales are the principal predators of common dolphins. When under threat individuals can be seen moving closer together. Dolphins have also been spotted with shark-bite scars indicating that sharks may predate on this species.
Human impact
Large numbers of short-beaked common dolphins die in tuna purse seine fisheries in the eastern tropical Pacific and in set net fisheries around the world. In New Zealand common dolphins are caught in trawl fisheries each year. Tourism activities have also been found to affect the normal behaviour of these dolphins and studies have shown them attempting to avoid approaching vessels through the use of evasive behaviours (Au & Perryman, 1982). Boat strike is also a threat in areas of high boating activity such as in the Bay of Islands. Again, common sense rules should apply when boating around these dolphins to reduce stress on the animals. Such rules are outlined in the Marine Mammal Protection Regulations (1992).
Contacts
To report whale or dolphin sightings or strandings phone the DOC HOTline 24 hour emergency number:
0800 DOC HOTline (0800 362 468)