page_title: Silky shark
section_title: Distribution and habitat
hierarchical_section_title: Silky shark / Distribution and habitat
caption_attribution_description: English: An image of the Silky Shark. The photo was taken on 21 October 2006 at Small Brother Reef in Egypt in the Red Sea. Photo: Johan Lantz, Malmö SWEDEN, 2006
context_page_description: The silky shark, also known by numerous names such as blackspot shark, grey whaler shark, olive shark, ridgeback shark, sickle shark, sickle-shaped shark and sickle silk shark, is a species of requiem shark, in the family Carcharhinidae, named for the smooth texture of its skin. It is one of the most abundant sharks in the pelagic zone, and can be found around the world in tropical waters. Highly mobile and migratory, this shark is most often found over the edge of the continental shelf down to 50 m. The silky shark has a slender, streamlined body and typically grows to a length of 2.5 m. It can be distinguished from other large requiem sharks by its relatively small first dorsal fin with a curving rear margin, its tiny second dorsal fin with a long free rear tip, and its long, sickle-shaped pectoral fins. It is a deep, metallic bronze-gray above and white below.
  With prey often scarce in its oceanic environment, the silky shark is a swift, inquisitive, and persistent hunter. It feeds mainly on bony fishes and cephalopods, and has been known to drive them into compacted schools before launching open-mouthed, slashing attacks.
context_section_description: The silky shark has a cosmopolitan distribution in marine waters warmer than 23 °C (73 °F). In the Atlantic Ocean, it is found from the U.S. state of Massachusetts to Spain in the north, and from southern Brazil to northern Angola in the south, including the Mediterranean Sea, Gulf of Mexico, and Caribbean Sea. It occurs throughout the Indian Ocean, as far south as Mozambique in the west and Western Australia in the east, including the Red Sea and the Persian Gulf. In the Pacific Ocean, the northern extent of its range runs from southern China and Japan to southern Baja California and the Gulf of California, while the southern extent runs from Sydney, Australia, to northern New Zealand to northern Chile. Based on life history differences, four distinct populations of silky sharks have been identified in ocean basins worldwide: in the northwestern Atlantic, in the western and central Pacific, in the eastern Pacific, and in the Indian Ocean.
  Primarily an inhabitant of the open ocean, the silky shark is most common from the surface to a depth of 200 m (660 ft), but may dive to 500 m (1,600 ft) or more. Tracking studies in the tropical eastern Pacific and northern Gulf of Mexico have found that cruising silky sharks spend 99% of their time within 50 m (160 ft) of the surface, and 80–85% of their time in water with a temperature of 26–30 °C (79–86 °F); the pattern was constant regardless of day or night. This species favors the edges of continental and insular shelves, often over deepwater reefs and around islands. Its range extends farther north and south along continental margins than in oceanic waters. On occasion, it may venture into coastal waters as shallow as 18 m (59 ft). Silky sharks are highly mobile and migratory, though the details of their movements are little-known. Tagging data have recorded individual sharks moving up to 60 km (37 mi) per day, and covering distances up to 1,339 km (832 mi). Larger sharks generally move longer distances than smaller ones. In the Pacific Ocean and possibly elsewhere, it spends the summer at slightly higher latitudes, particularly during warmer El Niño years. In the northern Atlantic, most sharks follow the Gulf Stream northward along the U.S. East Coast. In the Gulf of Aden, it is most common in late spring and summer.
caption: The silky shark is typically encountered in open water.
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