Großer Tümmler

 

Klassifikation:

Weltweite Population

Beschreibung und Lebensweise

Physical Description 
The bottlenose dolphin is the most familiar dolphin species because of its popularity in the aquaria industry and in television and the media. The bottlenose dolphin is a large, robust dolphin with a tall dorsal fin. Color ranges from blue grey to grey to brownish to black with lighter sides and belly, sometimes with a pinkish hue. Spots may be seen on the sides and belly. Bottlenose dolphins lack a distinctive color pattern, which is characteristic of other species. They have a short beak separated from the melon by a noticeable crease, and the tail flukes are deeply notched. Adults are 1.9-3.8 meters (6.2-12.5 feet) in length and weigh between 140-650 kilograms (309-1,433 pounds). Males tend to be larger than females. Calves are approximately 1.0-1.3 meters (3.3-4.3 feet) and 25 kilograms (55 pounds) at birth.
 
Natural History 
The natural history of bottlenose dolphins has been studied in detail. They inhabit temperate and tropical waters around the world. Two forms are recognized: a coastal form that prefers shallow, warm inshore waters of bays and rivers and usually travels in small groups of less about ten individuals; and an offshore form that inhabits deep, offshore waters and usually travels in groups in the 10s or 100s. These dolphins are very active and large pods may include other species of dolphin as well as pilot whales. Bottlenose dolphins are curious animals that can travel at great speeds. They can be found bow riding on the wake of boats or jumping out of the water acrobatically. Bottlenose dolphins can interbreed with other dolphin species and have done so in the wild and in captivity. Females reach sexual maturity between 5 and 10 years of age, males between eight and 12 years. A single calf is born every 3 to 6 years and weaned between 12 and 18 months. Bottlenose dolphins feed on a variety of prey and use various foraging techniques including hunting alone, hunting cooperatively, and in some areas, driving fish onto mud banks and beaching themselves to catch them.

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Status der Art

Status 
The bottlenose dolphin is not listed by the International Union for the Conservation of Nature and Natural Resources (IUCN) but is listed on Appendix II of the Convention on the Trade in Endangered Species of Fauna and Flora.
 
Threats to the Species 
Bottlenose dolphins are taken incidentally in gillnets, purse seines and shrimp trawls in various commercial and recreational fisheries. They are also killed in shark nets and may be taken in drive fisheries. Large directed kills have taken place in the Black Sea by Russia and Turkey and local populations have been depleted. Directed takes still occur in Peru, Sri Lanka and Japan for human consumption. Live capture for display in aquaria has affected some populations as well with more than 1,500 being taken from the waters of the U.S. by 1980. Live capture continues today in countries such as Mexico, Cuba and Japan. Bottlenose dolphins can be wounded or killed in collisions with boats and feeding wild dolphins is thought to negatively affect the behavior of individuals and local populations.

International Trade
Listed on CITES Appendix II which prohibits international trade.

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Autor und Quellen

Sources
CITES.  2001.  Atlantic white-sided dolphin.  http://www.cites.org.

Geraci, J.R. and V.J. Lounsbury.  1993.  Marine mammals ashore;  A field guide for strandings.  Texas A&M University Sea Grant College Program.  Galveston, Texas.305pp.

Wynne, K. and M. Schwartz.  1999.  Guide to marine mammals & Turtles of the U.S. Atlantic & Gulf of Mexico.  Rhode Island Sea Grant.  114pp.

Jefferson, T.A., S. Leatherwood and M.A. Webber.  1993.  Marine mammals of the world.  United Nations Environment Programme.  Food and Agriculture Organization of the United Nations.  320pp.

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