01/05/2013
The short-beaked common dolphin (Delphinus delphis) is the commonest dolphin species (1), but exact numbers are unknown (3). It is easily identified owing to the obvious 'hourglass' pattern on the flanks, which creates a dark V-shape below the dorsal fin (1). Considerable variation in colours and patterns exists within this species (3), and in 1994 a new species, the long-beaked common dolphin was recognised, based on both anatomical and genetic differences
Biology
These fast-swimming dolphins are highly active (1), often leaping clear of the water (breaching), and slapping their flippers on the water surface (lobtailing) (3). The short-beaked common dolphin occurs in large groups (3) of between 10 and 500 individuals (1), the size of group depending on both the time of day and year (3). The approach of these groups can be detected from miles away (1), and some noises made by this species can be heard from above the surface of the water (3). They feed on small fish and cephalopods such as squid (1), and are known to use co-operative methods of hunting (4). They make short dives typically of between 10 seconds and 2 minutes, but dives lasting for as long as 8 minutes have been recorded (3).
Top
Range
Occurs in all tropical, subtropical and warm temperate seas (5). The short-beaked common dolphin is common, with a wide distribution in the eastern north Atlantic Ocean. Around the UK it is abundant in the western approaches to the English Channel, west of Ireland, in the southern Irish Sea and in the vicinity of the Inner Hebrides, reaching as far north as Skye
Habitat
Prefers waters that have a surface temperature higher than ten degrees Celcius (4). The short-beaked common dolphin is less commonly seen in water shallower than 180 metres
Status
The short-beaked common dolphin is classified as Least Concern (LC) on the IUCN Red List (1). Listed on Annex IV of the EC Habitats Directive; North and Baltic Sea, western Mediterranean, Black Sea and eastern tropical Pacific populations are listed under Appendix II of the Bonn Convention, and Appendix II of the Bern Convention (7). All cetaceans (whales and dolphins) are listed on Annex A of EU Council Regulation 338/97; they are therefore treated by the EU as if they are included in CITES Appendix I, so that commercial trade is prohibited. In the UK all cetaceans are fully protected under the Wildlife and Countryside Act, 1981 and the Wildlife (Northern Ireland) Order, 1985
Threats
Known threats to the short-beaked common dolphin include entanglement in fishing nets, human disturbance, noise and chemical pollution, lack of food and hunting (3).
Top
Conservation
A UK Biodiversity Action Plan priority species, the short-beaked common dolphin is protected in UK waters by the Wildlife and Countryside Act 1981 and the Wildlife (Northern Ireland) Orders, 1985; it is illegal to intentionally kill, injure, or harass any cetacean (whale or dolphin) species in UK waters (2). The Agreement on the Conservation of Small Cetaceans in the Baltic and North Seas (ASCOBANS) has been signed by 7 European Countries, this includes the UK. Provision is made under this agreement to set up protected areas, promote research and monitoring, pollution control and increase public awareness
