Spinner shark

What it is

This requiem shark has a slender, streamlined body with a long, pointed snout and small circular eyes. Its colour is grey above, sometimes with a bronze sheen, and white below. Adults display black tips on the second dorsal, pectoral, anal, and lower caudal fins. The first dorsal fin is triangular and set back behind the pectoral fins. It grows up to 3 metres long, though most adults are smaller. The teeth are narrow and serrated in the upper jaw, suited for grasping prey rather than cutting large chunks.

Where it lives

The species inhabits tropical and warm temperate seas across the globe, absent only from the eastern Pacific. In the Atlantic, it ranges from North Carolina to Argentina, including the Gulf of Mexico and Caribbean. Eastern Atlantic populations extend from North Africa to Namibia. Indian Ocean records cover South Africa, Madagascar, the Red Sea, India, and Indonesia. Pacific sightings include Japan, Vietnam, and Australia. Some individuals have migrated through the Suez Canal into the Mediterranean. They occupy coastal shelves and offshore waters down to 100 metres, preferring depths under 30 metres.

How it lives

Swift and active, these sharks often form large schools separated by age and sex. They hunt small bony fish like sardines, herring, and mullet, as well as squid and octopus. A distinctive feeding tactic involves charging vertically through prey schools while spinning on their axis. This momentum frequently launches them out of the water. They also scavenge discards from shrimp trawlers. Juveniles stay in cooler shallow waters, while adults may migrate seasonally, moving inshore during summer and to deeper southern waters in winter.

Breeding and life cycle

Females bear live young after a gestation of 11 to 15 months. Embryos initially rely on a yolk sac, which later forms a placental connection for nutrient transfer. Litters contain three to 20 pups, born in coastal nurseries like bays and estuaries. Newborns measure about 60 to 77 cm. Growth is rapid in the first year, slowing as the shark matures. Males reach maturity at four to five years, while females take seven to eight years. Reproduction typically occurs every other year, with mating taking place in spring and summer.

Fish and people

Commercial fisheries value this shark for its high-quality meat, fins, liver oil, and skin. In the United States, the meat is often sold labelled as blacktip shark. Recreational anglers prize it as a strong fighter that leaps from the sea. While generally not dangerous to humans, excited individuals near food sources may bite. Sixteen unprovoked attacks have been recorded, none fatal. Conservation groups list the species as Vulnerable due to habitat degradation and heavy fishing pressure in coastal zones.

Status and threats

The International Union for Conservation of Nature assesses the global population as Vulnerable. Coastal habits expose the species to human exploitation and environmental damage. In the northwest Atlantic, management falls under the US National Marine Fisheries Service plan for large coastal sharks. Quotas and bag limits aim to control harvest levels. Confusion with the similar blacktip shark complicates accurate population monitoring and reporting in many fisheries.

Questions people ask about Spinner shark

Good reading and sources

• Spinner shark on WikipediaEncyclopedia
• More photos on Wikimedia CommonsPhotos
• Wikidata recordOpen data