08 June 2012

Indo-Pacific Bottlenose Dolphin – Half Moon Bay

Whilst at Half Moon Yacht Club, Sunfish Beach, Half Moon Bay with the family on Friday evening, we saw an Indo-Pacific Bottlenose Dolphin catching fish just offshore from the swimming area. This is the first dolphin I have seen in Saudi Arabia although my wife and children saw one at the same place last year. The dolphin stayed quite close to shore but never showed very much of itself apart from its back and fin, very much like the photogrpah below which was taken by Con Foley in Singapore and shows an Indo Pacific Bottlenose Dolphin. This photograph is coyright and is used by kind permission of Con Foley who's excellent website is here

The Bottlenose Dolphin (Tursiops truncatus) has two main varieties; a smaller, inshore form and a larger, more robust form that lives mainly offshore. They were all previously recognised as a single species the Bottlenose Dolphin T. truncatus, but recently the genus has been split into two species: the pan-tropical and temperate Tursiops truncatus and the endemic Indian Ocean Tursiops aduncus now called the Indo-Pacific Bottlenose Dolphin. T. aduncus is the species sighted in Saudi Arabian waters with this species range more limited than the T. trucatus, covering from the east coast of Africa eastwards through the Persian Gulf, Arabian Sea and Bay of Bengal to Taiwan and Australia. In the Indian Ocean, T. aduncus is the predominant coastal species while T. truncatus is usually seen offshore. Bottlenose dolphins in general are highly active animals, frequently bow-riding and breaching. They typically show their forehead when surfacing but not the beak (unlike the humpback dolphin). These dolphins have a stocky, torpedo-shaped body, a short beak and pointed flippers. They are usually dark grey on the back with paler grey flanks and have a tall, sickle-shaped dorsal fin is positioned centrally on the back. Bottlenose Dolphins primarily feed by themselves, such as the one we saw in Half Moon Bay, but are known on occasion to form co-operative groups to catch schools of prey. They have a broad diet, with a wide variety of fish and invertebrates being taken. The main threats facing this dolphin in the Arabia Gulf are pollution, habitat degradation and entanglement in fishing nets. Like all dolphins they are also susceptible to human disturbance and noise pollution.