Spinner shark  (Carcharhinus brevipinna)

Classified as Near Threatened (NT) on the IUCN Red List. North-west Atlantic subpopulation classified as Vulnerable (VU) (1).

The spinner shark is a long, slender-bodied shark, so named for its habit of leaping from the water, when hooked or pursuing prey, and spinning in mid-air along the axis of its body (2) (3). This species has greyish-bronze upperparts fading to white on the underside, with a faint white band running along the sides. The fins are slender, with pointed or rounded tips. In some large juveniles and adults, distinctive black or grey tips may be found on the pelvic, dorsal and anal fins, as well as on the upper lobe of the caudal fin (4).

The spinner shark has a worldwide distribution, occurring in most of the world’s major oceans, mainly within subtropical, coastal waters (1).

The spinner shark is generally found in subtropical inshore or nearshore waters, from shallow regions within bays, to depths of up to 100 metres (4).

A fast and agile predator, the spinner shark preys on a variety of pelagic, bony fish including sardines, herrings, mullet and tunas, but will also take small sharks, cuttlefish, squids and octopi (1) (4). This species employs an unusual method of hunting, which involves swimming rapidly through schools of fish, spinning on its axis, and snapping in all directions at the scattering prey, culminating in an impressive leap from the water surface. Although high-up in the food chain, the spinner shark does occasionally fall prey to larger shark species, with the smaller juveniles and sub-adults being especially vulnerable (4).

Populations of the spinner shark found in the Gulf of Mexico and off the coasts of Florida and Louisiana are known to be highly migratory, forming schools that move inshore during the spring and summer to reproduce and feed (4) (5). Like many shark species, the female spinner shark gives birth to live young (2) (4), producing between 3 and 15 well-developed offspring after a gestation period of around 12 to 15 months (4). The newborn sharks quickly move into shallow estuarine waters where sources of food are numerous and predation pressure is less intense (4).

Despite the fearsome reputation of many large sharks, few are considered to be dangerous to humans. Only thirteen attacks have ever been recorded for this species, none of which have proven to be fatal (4). As with other shark species, the real cause for concern is the threat posed to the spinner shark by humans (6).

Due to the fact that the spinner shark is a common, widespread species found in nearshore habitats, it suffers from heavy recreational and commercial fishing pressure, especially in the north-west Atlantic. The meat is used for human consumption, the liver for vitamin oil production, and the fins are likely to be sold in the oriental shark trade. This exploitation is compounded by the fact that the spinner shark’s nursery grounds are found inshore. Therefore a large proportion of sharks caught may be pregnant females, while the estuary-dwelling pups may suffer significantly from the effects of human-induced habitat degradation (1).

While there are no specific conservation measures targeting the spinner shark (1), several conservation organisations, such as the Save Our Seas Foundation, the Shark Research Institute, the Shark Trust, and Bite-back, are working diligently to eliminate unsustainable shark fishing practices (5) (6) (7) (8).

View information on this species at the UNEP World Conservation Monitoring Centre.

To learn more shark conservation visit:

• Save Our Seas Foundation:
  www.saveourseas.com

• Shark Research Institute:
  www.sharks.org
• The Shark Trust:
  www.sharktrust.org
• Bite-back:
  www.bite-back.com