(Meyen, 1833) - Striped dolphin
Distinctive Characteristics
The striped dolphin has the body shape typical of the Stenella and Delphinus species and it is somewhat more robust than spinner and pantropical spotted dolphins, with a falcate dorsal fin and a moderately long beak.
The colour pattern is stunning: a white or pinkish belly and dark grey back are separated by a light grey flank. A variable light grey spinal blaze extends from the flank area to just under the dorsal fin. The black beak sends back a stripe which encircles the eye and then widens and runs back to the anus. There is an eye to flipper stripe and an accessory stripe between the other 2. The appendages are dark grey to black.
The mouth contains 40 to 55 small, sharp teeth in each tooth row.
Can be confused with
Although the body shape is similar to that of other species in the Stenella and Delphinus group, striped dolphins are generally easy to distinguish by their unique colour patterns. Fraser's dolphins also have an eye-to-anus stripe, but are much more robust, with tiny appendages.
Size
Adult striped dolphins are up to 2.6 m long; males are slightly larger than females. Maximum weight is about 156 kg. Newborns are about 1 m in length.
Geographical Distribution
Although also primarily a warm water species, the range of the striped dolphin extends higher into temperate regions than do those of its closest relatives, the spotted and spinner dolphins. Limits are about 50°N and 40°S. Striped dolphins also are generally restricted to oceanic regions, and are seen close to shore only where deep water approaches the coast.
Biology and Behaviour
Striped dolphins are fast swimmers, and tend to be more easily alarmed than other tropical dolphins; this and their colour pattern have prompted fishermen to call them “streakers.” Although most herds number between 100 and 500 individuals, striped dolphins sometimes assemble into herds of thousands. Off Japan, there appears to be some age and sex segregation of these large herds.
Off Japan, where the biology of this species has been best studied, there are 2 calving peaks: 1 in summer, another in winter.
The diet of this species consists primarily of small, mid-water squid and fish, especially lanternfish.
Exploitation
Striped dolphins are taken in the tuna purse seine fishery in the eastern tropical Pacific, although in much smaller numbers than are spotted, spinner, and common dolphins. This species is the major target of a large drive fishery off Japan, where several thousand are taken each year. They are also caught in the small cetacean fishery of Sri Lanka, in the Indian Ocean. There appears to be some direct capture of striped dolphins in the northeast Atlantic and Mediterranean Sea.
IUCN Status
Insufficiently known.