Fin whale
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Classification:
Population mondiale
Description Et Histoire Naturelle
Physical DescriptionFin whales, also called finback whales, are second in size only to the blue whale. Like other whales from the family Balaenopteridae, fin whales have a streamlined body and broad, flat V-shaped head with a well-developed rostral ridge from the blow hole towards the end of the rostrum. Adults grow 18-24 meters (59-78.7 feet) in length, with females growing larger than males. Calves are 5.5-6.5 meters (18-21.3 feet) at birth. Fin whales are dark grey or brown with occasional light colored blotches on the back, and lighter on the belly. One or two light colored chevrons extend across the back behind the blow holes. Fin whales are the only species to have asymmetrical coloring on the head; light-colored swirls (called the “blaze”) can be seen on the right side of the head and the right lower lip, upper lip and front portion of the baleen plates are also light-colored. The left side is dark grey to behind the blow hole, including the baleen. The dorsal fin is sickle-shaped and situated towards the tail, and is relatively larger than that of the blue whale. The tail flukes are wide and pointed at the tips with a noticeable median notch. The tall, 10 meter (33 foot) vertical column of blow can be recognized from a distance.
Natural History
Fin whales are cosmopolitan in their distribution, inhabiting all the major oceans where they feed on krill and small, schooling fish. Although they can be found in deep waters, they are more commonly concentrated in coastal and shelf waters. Fin whale movements are complex and their broad range may indicate that they do not migrate as other whale species do. Fin whales are usually found alone or in pairs but they may form groups of a 100 or more on the feeding grounds. Fin whales are one of the fastest of the large whales and can reach speeds of 25 knots. They are not particularly active at the surface and rarely fluke up before diving, although they do arch their backs and raise their tail stocks.
Calves are born once every 2 or 3 years following a gestation period of 11 to 12 months. Like blue whale calves, fin whale calves are weaned at between 6 and 8 months. The worldwide population of fin whales is unknown. Fin whales are cosmopolitan in their distribution, inhabiting all the major oceans where they feed on krill and small, schooling fish. Although they can be found in deep waters, they are more commonly concentrated in coastal and shelf waters. Fin whale movements are complex and their broad range may indicate that they do not migrate as other whale species do. Fin whales are usually found alone or in pairs but they may form groups of a 100 or more on the feeding grounds. Fin whales are one of the fastest of the large whales and can reach speeds of 25 knots. They are not particularly active at the surface and rarely fluke up before diving, although they do arch their backs and raise their tail stocks.
Situation De L'Espèce
StatusToday the fin whale is listed as Endangered by the International Union for the Conservation of Nature and Natural Resources (IUCN) and included on Appendix I of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES).
Threats to the Species
The fin whale was spared from early hunting particularly by its speed. However, the 20th century invention of both steam-powered vessels and explosive harpoons changed all that and the fin whale was hunted in larger numbers than any other whale species during this time period. In the Southern Hemisphere alone, approximately 725,000 fin whales were killed. Although provided protection by the International Whaling Commission’s (IWC) whaling moratorium in 1986, fin whales continued to be hunted by Iceland for scientific purposes. Current threats include disturbance from seismic operations; collision with large vessels; entanglement in fishing gear; pollution (including noise pollution and increasing amounts of plastic debris at sea, oil spills and dumping of industrial wastes); and a decrease in krill. Fin whales would also most likely be targeted by commercial whaling should such an activity resume.
International Trade
Listed on CITES Appendix I which prohibits international trade.
Auteur Et Sources
SourcesIUCN. 2001. The 2000 IUCN Red List of Threatened Species. http://www.redlist.org.
Jefferson, T.A., S. Leatherwood and M.A. Webber. 1993. Marine Mammals of the World. FAO Species Identification Guide. UNEP, Rome. 320pp.
Leatherwood, S. and R.R. Reeves. 1983. The Sierra Club Handbook of Whales and Dolphins. Sierra Club Books, San Francisco. 302 pp.
Reeves, R.R., B.S. Stewart, P.J. Clapham and J.A. Powell. 2002. Guide to marine mammals of the world. National Audubon Society. 527pp.
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