Scientific Name: Stenella coeruleoalba (Meyen, 1833).
Common Name: Striped dolphin.
Classification: Odontoceti, family Delphinidae.
Physical notes: Up to 2.5 m and 160 kg. Slender and streamlined with a medium sized, slender beak and distinctive grey body pattern. Has a thin dark stripe that runs along the lower flanks from the eye to the underside of the tailstock and another from the eye to above the flippers.
Distribution and habitat use: Widely distributed mainly in tropical to warm temperate waters. Typically, in water deeper than 1000m. Generally, occurs outside the continental shelf but also close to shore were waters sufficiently deep.
Group size: Normally seen in groups of 10 to 30 individuals, sometimes up to 500, with several thousand reported occasionally. Group size tends to increase the further offshore and deeper the water.
Life span: 55-60 years.
Gestation period: 12-14 months. Calves are born ca. 1/3 adult size and they reach maturity at 5 -15 years. Births take place from April-May. Juveniles are weaned after 8 – 20 months.
Diet and Feeding: Wide variety of small fish and squid that inhabit water 200-700m deep. Cooperative feeding techniques often used to herd prey. They can dive up to 700 m and hold their breath up to 10 minutes.
Typical Behaviour: Fast moving, energetic and acrobatic, often leaping, breaching up to 5-7m high and spinning, but generally shy of vessels. Performs a unique behaviour called ‘roto-tailing’ – high arcing leap while vigorously whipping its tail in a circle.
Population status: Minimum 2.4 million worldwide. Population trend unknown. In continental waters of Portugal around 20 000 individuals were estimated between 2010-2015.
Threats: Hunting, persecution, bycatch and pollution levels.
IUCN status: Least concern worldwide (2018) and in Portugal (2023). Mediterranean sub-population is Vulnerable (2010).
Carwardine, M. (2022). Whales, Dolphins and Porpoises. Bloomsbury Wildlife. London, United kingdom.
Ferreira, M., Eira, C., López, A., & Sequeira, M. (2023). Stenella coeruleoalba golfinho-riscado. In Mathias, M. L. (coord.), Fonseca, C., Rodrigues, L., Grilo, C., Lopes-Fernandes, M., Palmeirim, J. M., Santos-Reis, M., Alves, P. C., Cabral, J. A., Ferreira, M., Mira, A., Eira, C., Negrões, N., Paupério, J., Pita, R., Rainho, A., Rosalino, L. M., Tapisso, J. T., & Vingada, J. (eds.): Livro Vermelho dos Mamíferos de Portugal Continental. Fciências.ID, ICNF, Lisboa.
Shirihai, H. (2006). Whales, Dolphins and Seals: A Field Guide to the Marine Mammals of the World. Bloomsbury Wildlife. London, United Kingdom.
Still, R., Harrop, H., Stenton, T., & Dias, L. (2019). Europe’s Sea Mammals Including the Azores, Madeira, the Canary Islands and Cape Verde: A field guide to the whales, dolphins, porpoises and seals. Princeton University Press.