The Dusky Dolphin (Lagenorhynchus obscurus) is a highly gregarious (living in flocks) and acrobatic dolphin found in coastal waters in the Southern Hemisphere. It is very closely genetically related to the Pacific White-sided Dolphin, although current scientific consensus is that they are distinct species.
The Dusky Dolphin is short-to-medium in length in comparison with other species in the family. There is significant variation in size in the different population areas. The largest Duskys have been encountered off Peru, where they are up to 7 ft (210cm) in length and 200 pounds (100kg) in weight. The back of the dolphin is dark grey and dorsal fin is distinctively two-toned – the leading edge matches the back in color but the trailing edge is a much lighter grey white. Duskys have a long light grey patch on their foreside leading to a dark, grey short beak. The throat and belly are white. There are two blazes of white color running back on the body from the dorsal fin to the tail. Dusky Dolphins may easily be confused with Peale’s Dolphins when observed at sea.
Population and distribution
The population of Dusky Dolphins is. The Dusky Dolphin is distributed in coastal waters of Chile, Argentina and the Falkland Islands, Namibia and the west coast of South Africa and the east coast of New Zealand. There may also be resident populations off Tasmania and New South Wales and several small islands in the South Atlantic and Indian Oceans.
Conservation and dolphin-watching
Outside Peruvian coastal waters, the main danger to Dusky Dolphins from humans is the accidental catching. In the mid-1980s around 400-600 animals were killed annually off Patagonia due to dolphins becoming trapped in nets. Rates appear to have declined since then due to tighter regulations on the fishing industry. However in Peruvian waters in addition to accidental catches there is continuing deliberate catching via nets and harpoons. The number of animals killed each year in this area runs into the thousands and a conservationists’ cause for concern.