The striped dolphin has the body shape typical of the Stenella/Delphinus group, although it is somewhat more robust than spinner and pantropical spotted dolphins. The beak is moderate in length and the dorsal fin is tall and falcate. The color pattern is stunning: a white or pinkish belly and dark gray back are separated by a light gray flank. A variable light gray 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 also an eye to flipper stripe and a third accessory stripe just above it. The appendages are dark gray to black. The mouth contains 40-55 teeth in each tooth row. Adult striped dolphins are up to 2.6 m long; males are slightly larger than females. Maximum weight is about 156 kg.
Can be Confused With
Although the body shape is similar to that of other species in the Stenella/Delphinus group, striped dolphins are generally easy to distinguish by their unique color patterns. They are most likely to be confused with common dolphins (Delphinus spp.), but a good look at the color pattern will clear-up any problems. Fraser’s dolphins also have an eye-to-anus stripe, but are much more robust with very small appendages.
Although primarily a warm water species, the tropical/warm temperate range of the striped dolphin extends higher into temperate regions than do those of any other species in the genus (spotted and spinner/Clymene 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.
Ecology and Behavior
The habitat of striped dolphins include the continental slope and oceanic waters.
Striped dolphins are fast swimmers, and tend to be more easily alarmed than other tropical dolphins; this and their color 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. At least off Japan, there appears to be some age/sex segregation of such herds.
Off Japan, where the biology of this species has been best studied, there are two calving peaks: one in summer, another in winter. Newborns are about 1 m in length.
Feeding and Prey
Striped dolphins feed by seizing prey. They have a broad diet, dominated by: Squid > fish > other invertebrates
The diet of this species consists primarily of small, midwater squid and fish, especially lanternfish.
The IUCN lists the striped dolphin as “lower risk/conservation dependent”. In the United States, striped dolphins are not listed as threatened or endangered. Striped dolphins are the main delphinid species involved in small cetacean harpoon and drive fisheries in Japanese waters. Although catches vary widely, in past years they were over 20,000. This species has also been directly captured in the Caribbean, Sri Lanka, and occasionally in the Mediterranean. Incidental catches occur throughout the range in various types of fishing gear, especially purse seines and driftnets. Large numbers of this species were formerly caught in pelagic driftnets in the Mediterranean and in North Pacific. A massive die-off in the Mediterranean is thought to have been at least partly related to environmental contaminants.
The United States National Marine Fisheries Service has estimated the size of several populations of striped dolphins. The western North Atlantic population, from Florida to the Gulf of St. Lawrence, was estimated in 1998 to be 61,546 (CV = 0.40). The northern Gulf of Mexico stock was estimated using data from 1991-1994 to be 4,858 (CV = 0.44). The California/Oregon/Washington stock was estimated using data from 1991-1996 to be 20,235 (CV = 0.14). Estimates for the eastern tropical Pacific have been made for several recent years, the lowest in 1986, being 801,210 (CV = 0.191) and the highest in 1988, being 1,497,428 (CV = 0.139).
Aguilar, A. and J.A. Raga. 1993. The striped dolphin epizootic in the Mediterranean Sea. Ambio 22:524-528.
Archer, F.I. 2002. Striped dolphin Stenella coeruleoalba. pp. 1201-1203 in W.F. Perrin, B. Würsig and J.G.M. Thewissen, eds. Encyclopedia of marine mammals. Academic Press.
Archer, F.I. and W.F. Perrin. 1999. Stenella coeruleoalba. Mammalian Species 603:1-9.
Calzada, N., A. Aguilar, C. Lockyer and E. Grau. 1997. Patterns of growth and physical maturity in the western Mediterranean striped dolphins, Stenella coeruleoalba (Cetacea Odontoceti). Canadian Journal of Zoology 75:632-637.
Hassani, S., L. Antoine and V. Ridoux. 1997. Diets of albacore, Thunnus alalunga, and dolphins, Delphinus delphis and Stenella coeruleoalba, caught in the Northeast Atlantic albacore drift-net fishery a progress report. Journal of the Northwest Atlantic Fisheries Science 22:119-123.
Miyazaki, N. 1984. Further analyses of reproduction in the striped dolphin, Stenella coeruleoalba, off the Pacific coast of Japan. Reports of the International Whaling Commission Special Issue 6:343-353.
Perrin, W.F., C.E. Wilson and F.I. Archer III. 1994. Striped dolphin Stenella coeruleoalba (Meyen, 1833). pp. 129-159 in S.H. Ridgway and R. Harrison, eds. Handbook of marine mammals, Volume 5: The first book of dolphins. Academic Press.
Wurtz, M. and D. Marrale. 1993. Food of the striped dolphin, Stenella coeruleoalba, in the Ligurian Sea. Journal of the Marine Biological Association of the United Kingdom 73:571-578.