Common dolphins can be easily distinguished from other delphinid species by their distinct yellow and grey hourglass pattern along their sides, a dark black dorsal and a white belly. The global taxonomic status of the genus Delphinus remains unresolved due to the disagreement between morphology-based classifications and genetic investigations (Stockin et al., 2014). Despite this, they are divided into two distinct species: long-beaked (D. capensis), Gray 1828, and short-beaked (D. delphis), Linnaeus 1758 (Tavares et al., 2010).
In the Azores, the short-beaked variety is seen year-round. They are often more brightly coloured than the long-beaked variety, and they have a greater range, encompassing continental shelves and pelagic waters of the Pacific and the Atlantic (Evans, 1994; Tavares et al., 2010). This species prefers shallow and coastal waters along shelf edges but also areas with sharp bottom reliefs such as seamounts, most likely due to the distribution of their preferred prey (Cañadas & Hammond, 2008; Pierce et al., 2010).
Common dolphins are considered a very gregarious species since they live and forage in herds of a few tens of individuals that can aggregate into groups of several hundred individuals (Pusineri et al., 2007). During our trips, we can often see them break the surface at high speed and frequently bowride in front of our boats.
The major threats for common dolphins come from fishery by-catch mortality and/or prey depletion due to overfishing of common dolphin prey (Correia et al., 2019).
Common dolphin facts: (Reeves et al., 2002; Jefferson et al., 2011; IUCN (2020))
• Male: 2.7 m
• Calf: 0.8 – 1 m
• Male: 150 kg
Calving peak: in late Spring or early Summer (for higher latitudes)
German: Gemeiner Delfin
Dutch: Gewone dolfijn
Danish: Almindelig delfin
Polish: Delfin pospolity
Cañadas, A. & Hammond, P. S. (2008). Abundance and habitat preferences of the short-beaked common dolphin Delphinus delphis in the southwestern Mediterranean: implications for conservation. Endangered species research, 4(3), 309-331.
Correia, A. M., Gil, Á., Valente, R., Rosso, M., Pierce, G. J. & Sousa-Pinto, I. (2019). Distribution and habitat modelling of common dolphins (Delphinus delphis) in the eastern North Atlantic. Journal of the Marine Biological Association of the United Kingdom, 99(6), 1443-1457.
Evans, W. E. (1994). Common dolphin, white-bellied porpoise Delphinus delphis Linnaeus, 1758. Handbook of marine mammals, 5, 191-224.
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. Delphinus delphis. The IUCN Red List of Threatened Species 2008: e.T6336A12649851. https://dx.doi.org/10.2305/IUCN.UK.2008.RLTS.T6336A12649851.en. Downloaded on 19 March 2020.
Jefferson, T. A., Webber, M. A. & Pitman, R. L. (2011). Marine mammals of the world: a comprehensive guide to their identification. Elsevier.
Pierce, G. J., Caldas, M., Cedeira, J., Santos, M. B., Llavona, Á., Covelo, P., … & López, A. (2010). Trends in cetacean sightings along the Galician coast, north-west Spain, 2003–2007, and inferences about cetacean habitat preferences. Journal of the Marine Biological Association of the United Kingdom, 90(8), 1547-1560.
Pusineri, C., Magnin, V., Meynier, L., Spitz, J., Hassani, S. & Ridoux, V. (2007). Food and feeding ecology of the common dolphin (Delphinus delphis) in the oceanic Northeast Atlantic and comparison with its diet in neritic areas. Marine Mammal Science, 23(1), 30-47.
Reeves, R. R., B. S. Stewart, P. J. Clapham& J. A. Powell . 2002. Marine mammals of the world. National Audubon Society, Chanticleer Press, New York, New York, USA.
Stockin, K. A., Amaral, A. R., Latimer, J., Lambert, D. M. & Natoli, A. (2014). Population genetic structure and taxonomy of the common dolphin (Delphinus sp.) at its southernmost range limit: New Zealand waters. Marine Mammal Science, 30(1), 44-63.
Tavares, M., Moreno, I. B., Siciliano, S., Rodriguez, D., De O. Santos, M. C., Lailson-Brito Jr, J. & Fabian, M. E. (2010). Biogeography of common dolphins (genus Delphinus) in the Southwestern Atlantic Ocean. Mammal Review, 40(1), 40-64.