This pie chart shows the relative likelihood of observing particular other species commonly observed near Carcharhinus obscurus

Aquatic Regions:

Western Atlantic: southern Massachusetts to Florida (USA), Georges Bank, Bahamas, Cuba, northern Gulf of Mexico, Nicaragua, and southern Brazil. Eastern Atlantic: Canary Islands, Cape Verde, Senegal, Sierra Leone. Some records from the Mediterranean and Madeira may be based on Carcharhinus galapagensis. Indo-West Pacific: Red Sea[1], Mozambique and South Africa to Japan, China, Viet Nam and Australia. Eastern Pacific: southern California, USA to Gulf of California and the Revillagigedo Island. Highly migratory species, Annex I of the 1982 Convention on the Law of the Sea[2].

Range and Population:

This species has been recorded in the western Atlantic from Southern Massachusetts south to the northern Gulf of Mexico, and from Nicaragua to southern Brazil; various locations in the eastern Atlantic; the western Indian Ocean around South Africa, Mozambique, and Madagascar; eastern Indian Ocean off Western Australia; the western Pacific off the coasts of Japan, China, Viet Nam, and Queensland and New South Wales, Australia; and the eastern Pacific from Southern California to the Gulf of California, Revillagigedo Islands, and possibly Chile.[3]
Countries:Native:
Algeria; Australia; Bahamas; Brazil; Cape Verde; China; Colombia; Cuba; Djibouti; Fiji; French Guiana; Gambia; Guinea; Guinea-Bissau; Guyana; Hong Kong; Israel; Japan; Macao; Madagascar; Mexico (Revillagigedo Is.); Morocco; Mozambique; New Caledonia; Nicaragua; Portugal (Madeira); Senegal; Sierra Leone; South Africa; Spain (Canary Is.); Suriname; Taiwan, Province of China; Trinidad and Tobago; Tuvalu; United States (Florida, Georgia, Louisiana, Maryland, Massachusetts, Mississippi, New Jersey, North Carolina, Rhode Island, South Carolina); Venezuela; Viet Nam

[3][3]

Habitat Overview:

C. obscurus occurs along continental shorelines where it ranges from shallow inshore waters to the outer reaches of the continental shelf and adjacent oceanic waters. Although generally a bottom feeder, it can be found from the surface to a depth of 400 m (1240 ft). Adults of this species tend to avoid areas of low salinity and rarely enter estuaries. The young congregate in very shallow coastal water (nurseries) in estuaries and bays from New Jersey to Cape Hattaras.

This species is known to be highly migratory in the western Atlantic and eastern Pacific, moving north during the summer months and south in the winter. Males and females undertake these seasonal migrations separately.

Along the coast of South Africa, immature dusky sharks are known to undergo sex-segregated migrations with females moving north and males moving south. However, this phenomenon is complicated by the occurrence of temperature-regulated seasonal migration with sharks traveling southward during summer and northward in winter. This, in turn, is further complicated by the tendency for some sharks to move into deeper water during summer months.

In comparison, dusky sharks in western Australia undergo distinct seasonal migrations with both adolescents and adults moving inshore during summer and autumn.

May be found at depths of 0 to 400 meters. Usually found at depths of 200 to 400 meters.

Biome:

Brackish water, saltwater. Reef-associated.

Ecology Notes:

C. obscurus is a coastal-pelagic species of inshore and offshore warm-temperate and tropical waters. It occurs on continental and insular shelves and the oceanic waters adjacent to them, ranging from close inshore in the surf zone to well out to sea and from the surface to 400 m depth. It avoids estuaries and other reduced salinity areas. Adult dusky sharks are often seen offshore and are known to follow ships. In temperate and subtropical areas the species is migratory, moving north during the warmer summer months and retreating south when water temperatures drop. Diet includes a variety of reef, bottom, and pelagic bony fishes, along with other shark species, rays, crustaceans, cephalapods, barnacles, and whale meat.[3]

List of Habitats:9.1Marine Neritic - Pelagic 10.1Marine Oceanic - Epipelagic (0-200m)

Predators:

Young dusky sharks may fall prey to larger sharks including the bull shark. However, mature dusky sharks have few if any predators.

Parasites:

Pandarus sinuatus, a copepod, is parasitic on the body surface of the dusky shark.

In sections below, we make some habitat inferences based on the known habitat preferences of those species most commonly associated with Carcharhinus obscurus.

Zone:

a copepod, montane, subtropics, temperate, tropics.

Vegetation:

boreal forest, boreal shrubland, coniferous forests, cultivated areas, deciduous woods and forests, desert, fence rows, fields, forest edges, forests, gardens, grasslands, hardwood forests, mature forests, meadows, mediterranean-type shrubby vegetation, montane forests, open forests, pasture, pine forests, rain forest, shrubby vegetation, subarctic grassland, thickets, tropical forest, tundra grassland.

Terrain:

hillsides, pastureland, roadsides, streamsides, urban areas, valleys.

Soil and Rock:

marl, sandy areas, sandy soil.

Water in Area:

along rivers, bays, bogs, brackish water, coral reef, ditches, dry areas, estuaries, lagoon, lakes, marshes, pelagic, ponds, river banks, rivers, saltwater, shores, streams, subtidal muddy, swamps, swampy areas.

Slopes in Area:

hillsides.