The Striped Dolphin (Stenella coeruleoalba) is an extensively studied dolphin that is found in temperate and tropical waters of all the world’s oceans.
Taxonomy
The Striped Dolphin is one of five species traditionally included in the genus Stenella; however, recent genetic work by LeDuc et al. (1999) indicates that Stenella, as traditionally conceived, is not a natural group. According to that study, the closest relatives of the Striped Dolphin are the Clymene Dolphin, the Common Dolphins, the Atlantic Spotted Dolphin, and “Tursiops” aduncus, which were formerly considered a subspecies of the Bottlenose Dolphin. The Striped Dolphin was discovered by Meyen in 1833. The specific name coeruleoalba (from Latin caeruleus ‘dark blue’ and albus ‘white’) refers to the characteristic blue and white stripes on the flanks.
Physical description
The Striped Dolphin has a similar size and shape to several other dolphins that inhabit the waters that it does. However its coloration is very conspicuous and makes them relatively easy to distinguish at sea. The underside is white or pink. There are one or two dark blue bands that run from the bottom of the eye to the flipper. These bands widen to the width of the flipper, which are the same size. There are two further blue stripes running from behind the ear – one is short and ends just above the flipper. The other is longer and thickens along the flanks until it curves down under the belly just prior to the tailstock. Above these stripes the dolphin’s flanks are colored light blue. The back, dorsal fin, melon and beak are dark blue. There is also a dark blue patch around the eyes. The lips are white. The tailstock is the same mid-blue color as the middle stripe of the flank. At birth individuals weigh about 10 kg and are up to a meter long. By adulthood they have grown to 7.5 ft (2.4 m ) in females or 8 ft (2.6 meters) in males and the females weigh 330 pounds (150 kg ) or the males weigh 352 pounds (160 kg). Research suggests that sexual maturity was reached at 12 years in Mediterranean females and in the Pacific at between 7 and 9 years. Longevity is about 55-60 years. Gestation lasts approximately 12 months and there is a three or four year gap between calving.
In common with other dolphins in its genus, the Striped Dolphin moves in large groups – usually in excess of 100 individuals in size. Groups may be smaller in the Mediterranean and Atlantic. They may also mix with Common Dolphins. They Sometimes approaches boats in the Atlantic and Mediterranean but this are dramatically less common in other areas, particularly in the Pacific where it has been heavily exploited in the past.
The Striped Dolphin feeds on small pelagic fish and squid.
Population and distribution
The Striped Dolphin likes temperate or tropical, offshore waters. It is found in abundance in the North and South Atlantic Oceans, including the Mediterranean and Gulf of Mexico, the Indian Ocean and the Pacific Ocean. In the western Pacific, where the species has been extensively studied, a distinctive migration pattern has been identified. This has not been the case in other areas. The dolphin appears to be common in all areas of its range, though that may not be continuous in areas of low population density do exist. The total population is in excess of two million.
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