Stenella coeruleoalba, more commonly known as the striped dolphin, is typical of the family Delphinidae; they have a fusiform body, characteristic prominent notch in the flukes, tall dorsal fins and long, narrow flippers(1). The prominent beak contains 40-55 small pointed teeth in each row of the mouth. The dorsal fin is tall and narrow-based and located on the middle of the back. S. coeruleoalba ranges in body length from 220cm to 236cm (2), the longest recorded specimen was 2.56m and the maximum weight recorded was 156kg.
In the field, they are most likely confused with common dolphins (Delphinus delphis) and other similar-sized species, but can easily be distinguished by their robust body and coloration (3).
Striped dolphins are typically bluish-gray in color with a dark dorsal cape and light (usually white) ventral coloration (4). They are called ‘striped’ dolphins because of the dark bluish-black stripe running across the entire length of the body, from the eye to the anus, and because they possess black flipper stripes (1).
There are approximately 5 species in the Genus Stenella; S. attenuata, Pantropical spotted dolphin, S. clymene¸ Clymene dolphin, S. frontalis, Atlantic spotted dolphin and S. longirostris, Spinner dolphin.
S. coeruleoalba is primarily found in warm temperate and tropical oceanic regions, they are only seen close to shore where the deep water approaches the coast (5). S. coeruleoalba appears to avoid sea surface temperatures of less than 20°C (2).
In the North Pacific, the striped dolphin is connected with productive regions associated with upwelling as well as the oligotrophic waters of the central North Pacific gyre (1). The species is oceanic off the coast of South Africa; its distribution is correlated with the warm Agulhas current at depths over 1,000m beyond the continental shelf (6). In the western North Atlantic, S. coeruleoalba are found offshore of the Gulf Stream in the continental slope waters (7), whilst in the Mediterranean they are associated in the productive waters beyond the continental shelf.
The mating season of the striped dolphin is in the autumn for the Mediterranean and for the western north Pacific it is in the winter and early summer (1). The sexual maturity of S. coeruleoalba differs between genders; the males reach sexual maturity at 7-15 years old, whilst for the females it is 5-13 years old (2).
Typically, the gestation period lasts 12-13 months, resulting in a single calf which will measure less than a metre and weigh just 11 kilograms (1). Females usually have a four year interval for calving and rest 2-6 months between lactation and the next breeding period (2).
The striped dolphin is a widely-distributed species; it has been observed world-wide in tropical and warm-temperate waters of the Atlantic, Pacific, Indian oceans and the Mediterranean (7).
In some regions S. coeruleoalba is found in all season, in others it is thought to be associated with the warm fronts of the oceanic currents. In the Mediterranean, seasonal movements are thought to occur with the dolphins moving towards the northern part of the basin as the sea surface temperatures in the southern part increase (4). Sighting data also suggest seasonal movements of this species in the eastern tropical Pacific (8).
Group size in S. coeruleoalba ranges from a few individuals to over one-thousand individuals, but most schools consist of 100-500 dolphins (1). Usually there are three types of schools; breeding adults, non-breeding adults and juveniles (2). A Calf will only join the juvenile school approximately two years after weaning (1).
Similar to other delphinids, S. coeruleoalba will use clicks and whistles apparently as a form of communication (2).
Striped dolphins are particularly active; they will often be seen performing various aerial manoeuvres, such as breaching, chin slaps and bow-riding. They also have a unique behaviour called ‘roto-tailing’ in which “they make high arcing jumps while violently and rapidly performing several rotations with the tail before re-entering the water” (2).
The diet of the striped dolphin primarily consists of a variety of small, midwater and pelagic or benthopelagic fish (7); Mediterranean striped dolphins prey primarily on cephalopods, while north eastern Atlantic striped dolphins most often prey on fish, frequently cod (1).
S. coeruleoalba apparently feed in pelagic to benthopelagic zones, in the continental slope or oceanic regions, to depths as deep as 200-700 m (1).
Lower Risk in the IUCN Red List (7)
Appendix II of CITES
Appendix II of the Convention on Migratory Species
Annex A of EU Council Regulation 338/97
Description written by Ben Harvey (2009)
(1) Archer, F., W. Perrin. 1999. Stenella coeruleoalba. Mammalian Species, 603: 1-9.
(2) Savage, M. 2000. “Stenella coeruleoalba” (On-line), Animal Diversity Web. Accessed June 24, 2009 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Stenella_coeruleoalba.html
(3) Archer FI. 2002. Striped dolphins – Stenella coeruleoalba. In: Encyclopedia of marine mammals (Perrin WF, Würsig B, Thewissen JGM, eds.) Academic Press, San Diego, 1201-1203.
(4) CMS, 2004. CMS: Stenella Coeruleoalba, Striped Dolphin, Blue White Dolphin. [Online] Available at: http://www.cms.int/reports/small_cetaceans/data/S_ceoruleoalba/s_coeruleoalba.htm [Accessed 2009 June 02].
(5) Van Waerebeek K, Felix F, Haase B, Palacios DM, Mora Pinto DM, Munoz Hincapie M. 1998. Inshore records of the striped dolphin, Stenella coeruleoalba, from the Pacific coast of South America. Report of the International Whaling Commission 48: 525-532
(6) Ross, G.J.B. 1984. The smaller cetaceans of the south east coast of southern Africa. Annals of the cape Provinical Museums, Natural History, 15:173-410
(7) Hammond, P.S., Bearzi, G., Bjørge, A., Forney, K., Karczmarski, L., Kasuya, T., Perrin, W.F., Scott, M.D., Wang, J.Y., Wells, R.S. & Wilson, B. 2008. Stenella coeruleoalba. In: IUCN 2009. IUCN Red List of Threatened Species. Version 2009.1. <www.iucnredlist.org>. Downloaded on 24 June 2009.
(8) Perrin WF, Wilson CE, Archer FI II. 1994. Striped dolphin – Stenella coeruleoalba (Meyen, 1833). In: Handbook of Marine Mammals (Ridgway SH, Harrison SR eds.) Vol. 5: The first book of dolphins. Academic Pres, London, pp. 129-160.
(9) Wuertz, M., D. Marrale. 1993. Food of striped dolphin, Stenella coeruleoalba, in the Ligurian Sea. Journal of the Marine Biological Association of the United Kingdom, 73(3): 571-578.