Distribution & Habitat
There are two populations of Commerson's dolphins separated by 130° of longitude, or 8500 km (5,281 mi.).
- One population of Commerson's lives along the coasts of southern South America, the Falkland Islands, and South Georgia Island.
- On the west coast of South America in the Pacific Ocean, Commerson's are found as far north as Isla Grande De Chloé, Chile (42°45'S latitude).
- On the east coast of South America in the Atlantic Ocean, Commerson's dolphins are found as far north as southern Brazil at about 31°S latitude.
- The second population of Commerson's lives in shallow coastal waters around the Kerguelen Islands in the southern Indian Ocean.
- Despite the distance between South America and Kerguelen Commerson's dolphin populations, most scientists currently recognize only one Commerson's dolphin species.
The dolphin's distribution extends as far south as the South Shetland Islands, about 63°S latitude.
Commerson's dolphins are also frequently seen in the Strait of Magellan and around Tierra del Fuego, both about 54°S latitude.
- The Strait of Magellan is a narrow strip of water that connects the Pacific and Atlantic oceans. It also separates Tierra del Fuego, a 241 km (150 mile) long peninsula, from mainland South America.
Commerson's dolphins live in cold, inshore waters along coastlines, bays, harbors, and river mouths.
- They prefer waters less than 200 m (656 ft.) deep.
- The water temperature around their South America habitat ranges from 4°C to 16°C (39.2°F - 60.8°F).
- The water temperatures around Kerguelen Island are even colder, 1°C to 8°C (33.8°F - 46.4°F).
Commerson's dolphins are often seen swimming in or at the edge of kelp beds.
Population
The worldwide population of Commerson's dolphins is unknown. Population numbers and trends are poorly known for many species of ocean animals.
Since the Commerson's distribution is outside of the United States, U.S. Fish and Wildlife Service does not list this dolphin as either threatened or endangered.
Commerson's dolphins are protected in the South American countries of Argentina (since 1974) and Chile (since 1977).
- The international organization, IUCN - The World Conservation Union, lists the Commerson's dolphin in their 2003 IUCN Red List of Threatened Species in the "Data Deficient" category. This means that there is not enough information about the Commerson's dolphin population to assess the dolphin's risk of extinction.
- Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) is an international treaty that regulates trade in certain wildlife species. Most toothed whales, including Commerson's dolphins, are listed on CITES Appendix II. Appendix II includes species identified as threatened, or likely to become endangered if trade isn't regulated.
