SCIENTIFIC NAME: Tursiops truncatas

COMMON NAME: Bottlenose Dolphin

GEOGRAPHICAL DISTRIBUTION:

Found largely in coastal waters between 45N and 45S, and also in Northern European waters.

EXTERNAL ANATOMY:

Size: Adults from 1.9 to 3.8m, weighing up to 650kg. There is tremendous variation between populations, as different groups, known as ecotypes, are adapted to the different conditions in which they live.

NATURAL HISTORY:

HABITAT:

Coastal and Oceanic species
Populations generally occur in water in less than 30 miles from shore
Found in open coasts with strong surf to sheltered bays and waterways, lagoons, large estuaries and the lower reaches of rivers

FOOD & FEEDING:

Their feeding behaviour is extremely varied, depending on what is available. They may co-operate to forage on large schools of fish, or chase individual fish inshore. They have also been seen feeding behind trawlers and other fishing boats. This adaptability in feeding has undoubtedly contributed to their success, and enabled them to range so extensively.

LIFE CYCLE:

Life Span: 30+ years
Gestation period: 12 months
Peak seasons for mating: May and June
Calving interval: two to three years
Nursing lasts: calves suckle for up to 18 months
Sexual maturity begins at 9-10 for males and 10-13 years for females

BEHAVIOR:

Bottlenose Dolphins live in fairly open groups, generally containing no more than 20 animals, but large herds have been seen offshore.
They commonly associate with other dolphin species, and sometimes they may interbreed.

WORLD POPULATION:

Total worldwide population unknown

10,000-13,000 off northeastern United States
40,000 in Gulf of Mexico
35,000 in western North Pacific and Japanese coastal area
less than 10,000 in Mediterranean
250 off Indian Ocean coast of South Africa south of Natal
less than 1,000 in north of Natal

HUMAN INFLUENCES:

Bottlenose dolphins are taken incidentally and directly.
The largest direct expliotation has been in the Black Sea, but they are occasional victims of harpoon and drive fisheries in many places.
They are known to suffer from gillnets, shark nets, shrimp trawls and purse seine nets in the eastern Pacific tropical tuna fishery.
There is current controversy in the US senate about the import ban on tuna caught with large dolphin by-catch - this is something you may wish to find out more about.
Live-capture removals (the taking of dolphins for keeping in captivity have had large effects on populations of bottlenose in the Gulf of Mexico and the U.S. southeast coast.