Spinner dolphinStenella longirostris 
          
The Latin name derives from ‘longus’ for long and ‘rostrum’ for snout or beak. The common name for this dolphin derives from its behaviour - these dolphins typically spin around on their longitudinal axis as they breach, although they are often seen breaching in the normal way. The name Long-snouted spinner dolphin is now obsolete (Prof. W. Perrin, Scripps Institution of Oceanography, pers. com.) it derives from the time when scientists thought that the Clymene dolphin ( then called the ‘short-snouted spinner dolphin) was of the same species. It is now known that they are two different species and so both names have been simplified. The long-snouted spinner dolphin is now known only as the Spinner dolphin and the short-snouted dolphin is known as the Clymene dolphin. Spinner dolphins are found in the Atlantic, Indian and Pacific Oceans, where they are restricted to tropical, subtropical and less often warm, temperate regions. There are several varieties of spinner dolphin, these are geographically defined and differ in body shape, size and colour. At least four varieties have been recognised in the Eastern Pacific; the Grey Spinner Dolphin (which includes those found around Hawaii and the Islands of French Polynesia) the Whitebelly, the Eastern Pacific, and the Costa Rican spinner. 

Spinner dolphins are characterised by a long slender beak with a black tip and black lips, and an erect dorsal fin. The body is mainly grey, with a three toned colouration; dark grey along the back, a predominantly grey body and a pale grey/creamy white or pinkish under belly. Adults of this species are about 1.8-2.1m / 5.9ft -6.6ft in size and weigh 75-95kg / 165-209lbs (Dr. Michael Poole, Director, Marine Mammal Research Program, French Polynesia [CRIOBE}, pers com.), new-borns are 75-85cm in length. Spinner dolphins used to occur in herds of pods of >1000 animals, although nowadays occurrences of herds around 300 hundred are high, and in fact pods of 20 to 100 animals are more common. These dolphins are oceanic and are usually found far out to sea or off the coasts of oceanic islands. The first time we saw spinner dolphins we were about 150km/100miles off the coast of Suriname. A pod of 13 animals came to our bow; and stayed for about 20 minutes. We were traveling at ca.10knots, but spinner dolphins can easily keep up with a speed of 20 knots although this tires them more quickly. We went on observed Spinner Dolphins off the Marquesas Islands and mast recently off the coast of Tahiti and Moorea in the French Society Islands, in each case they came to bow ride, but stayed only five to ten minutes.

Spinner dolphins often associate with spotted dolphins, common dolphins and small to medium sized whales (e.g. pilot whales). In the Pacific they frequently associate with Yellowfin Tuna - much to their cost, since the Tuna Fishery between Hawaii, Mexico and Peru exploits this association. The tuna swim underneath the spinners in these waters, so the fishermen purposefully catch the dolphins in order to catch the tuna underneath. The spinner dolphins and the tuna accompanying them are herded together by high speed skiffs and then encircled with huge purse-seine nets. Pursing of the nets creates a bag in which both the dolphins and tuna are trapped and the mortality rate for the spinners is very high. During the last 30 years, as a result of this exploitation over 6-8 million dolphins have died, and in some cases populations have been reduced by over 85% from their pre-exploitation levels