Spinner SharkCarcharhinus brevipinna
This slender, gray-bronze shark is often mistaken for a blacktip shark, although the spinner is usually larger and has a black tip on its anal fin. It gets its name from how it feeds, swimming quickly through schools of fish, spinning along its axis, and snapping at fish in all directions. Although it can be a danger to humans, its teeth are designed for grabbing small prey rather than tearing at large prey, so it doesn't perceive humans as food unless it is confused during feeding.
English language common names for Carcharhinus brevipinna include spinner shark, blacktipped shark, great blacktip shark, large blacktip shark, long-nose grey shark, and shark. Other names from across the world include cação-agulha-preta (Portuguese), chotimushi (Marathi), galha-preta (Portuguese), hanazame (Japanese), jaqueton (Spanish), jarjur (Arabic), jarjur naudth (Arabic), karcharynos kontofteros (Greek), köpek baligi (Turkish), machote (Portuguese), marracho barbatana negra (Portuguese), mushi (Marathi), pating (Tagalog), requin nene pointe (French), requin tisserand (French), serra-garoupa (Portuguese), shivra (Kannada), spinnerhaai (Afrikans), squalo tissitore (Italian), sucuri-de-ponta-petra (Portuguese), tiburon aleta negra (Spanish), tolhaai (Dutch), and tubarão-tecelão (Portuguese).
Importance to Humans
Spinner sharks are taken primarily on longlines in the commercial shark fishery and as by-catch in the pelagic longline fishery. It is taken in lesser quantities by anglers trolling and stilt fishing. When it is hooked, this shark is known to make vertical spinning leaps out of the water. The flesh is marketed fresh and dried-salted for human consumption while the skins are valuable for leather and fins used in shark-fin soup.
Danger to HumansAlthough the spinner shark is not considered dangerous to humans, it may pose a threat if attracted to divers during spearfishing activities. According to the International Shark Attack File, the spinner shark has been responsible for 13 unprovoked attacks on humans resulting in no fatalities. However, its small, narrow teeth are much more suited to feeding on whole small fishes, not attacking large prey such as marine mammals and humans.
Due to the fact that this shark is frequently captured in the commercial and recreational fisheries, it is highly vulnerable to fishing pressure. In addition, the spinner shark utilizes inshore waters as nursery areas making it also susceptible to habitat alteration from development of shoreline areas.
The spinner shark is currently listed by the World Conservation Union (IUCN) as "Near Threatened" throughout its range and "Vulnerable" in the northwest Atlantic Ocean. The IUCN is a global union of states, governmental agencies, and non-governmental organizations in a partnership that assesses the conservation status of species.
Geographical DistributionThe spinner shark is found in the western Atlantic from North Carolina (U.S.) to the northern Gulf of Mexico and the Bahamas. This shark has also been reported in waters around Cuba. It also resides from southern Brazil to northern Argentina. In the eastern Atlantic Ocean, it is found from Spain to Namibia, including the southern Mediterranean Sea. In the Indo-West Pacific, the spinner shark is found in the Red Sea, south to South Africa, eastward to Indonesia, northward to Japan, and then south to Australian waters.
Distribution records are probably incomplete due to confusion over species identification with the blacktip shark (C. limbatus).
Distributed from inshore to offshore waters over continental and insular shelves, the spinner shark lives in subtropical regions primarily between 40°N and 40°S. Depth of habitat ranges from 0-328 feet (0-100 m). The spinner shark forms schools and is considered a highly migratory species off the Florida and Louisiana coasts and in the Gulf of Mexico, moving inshore during spring and summer months to reproduce and feed.
Although juvenile spinner sharks move into lower portions of bays with the tides, they avoid areas of low salinity.
The spinner shark is an active, fast swimming shark that is often seen leaping out of the water, spinning (from where it gets its common name), in pursuit of prey.
1. Anal, first, and second dorsal, pectoral, and lower caudal fins black-tipped in specimens less than 2.6 feet (0.8 m)
2. First dorsal fin fairly small, originating over or just behind free tips of pectoral fins, apex rounded
3. Snout pointed, as long or longer than width of mouth
This shark has a slender build with a long, pointed snout and small eyes. The lower jaw has a distinct notch along the trailing edge. The eyes are round and small in size. The first dorsal fin is small and semifalcate, originating above and behind the pectoral fin. This dorsal fin has a short rear tip followed by a moderately large second dorsal with a short rear tip. An inter-dorsal ridge is absent. The pectoral fins are narrow and falcate with narrow pointed or rounded tips. The caudal fin is slender with a narrowly rounded tip.
The teeth in the upper jaw of the spinner shark have narrow triangular cusps on broad bases. This differs from the blacktip shark, which has larger and broader teeth. The first few teeth are symmetrical and erect with subsequent teeth becoming slightly oblique. The outer three teeth are very low with finely serrated edges with smooth-edged tips.
The lower jaw teeth have more slender cusps on broad bases than the upper jaw. The tips of the teeth are not recurved forward as in the blacktip shark. The teeth are slightly oblique along the entire length of the jaw.
There are two small teeth located at the symphysis in the upper jaw and one small tooth in the lower jaw. The rows of teeth in each jaw vary in number from 14-18, but usually number 16/15.
The dermal denticles of the spinner shark are very closely arranged, even overlapping, concealing the skin. The blades are slightly raised and are broader than long. The ridges number usually 7 (rarely 5), with 7 very short or entirely even teeth.
Size, Age, and Growth
Spinner sharks reach a maximum total length of 9.8 feet (3 m) and a maximum weight of 198 pounds (89.7 kg). However, the average size of these sharks is about 6.4 feet (1.95 m) and 123 pounds (56 kg). Female spinner sharks mature at 5.6-6.6 feet (1.7-2.0 m) TL and males mature at 5.2-6.7 feet (1.6-2.0 m) TL. Upon reaching maturity, the spinner shark grows approximately 2 inches/yr (5 cm/yr), reaching maximum size at 10-20 years of age. This species is generally smallest in the northwestern Atlantic and largest in the Indian Ocean and Indo-West Pacific.
According to one study, the spinner shark grows approximately 8 inches (20 cm) during the first 6 months of life in waters off the Florida Atlantic coast.
Spinner sharks are "viviparous", or livebearing, with embryos nourished by a yolksac-placenta. The gestation period lasts 12-15 months with birth occurring at inshore locations during the summer months for stocks located off North America. Stocks located in the Mediterranean move inshore to give birth during summer off the North African coast. Litter size is from 3-15 pups, each measuring between 24-30 inches(60-75 cm) in length. The pups immediately move into shallow estuarine waters for protection from predators and readily available food sources.
Larger sharks are potential predators of the spinner shark, especially on juvenile and subadult individuals.
Kroyeria deetsi n.sp. is a parasitic copepod that has been reported to infect the gills of spinner sharks captured in the Indian Ocean. Other parasitic copepods reported associated with spinner sharks includeAlebion carchariae (body surface), Nesippus orientalis (gill arches and in the mouth), Perissopus dentatus (external nares and trailing edges of fins), Nemesis pilosus (gills) and Nemesis atlantica (gills).
Müller & Henle first described the spinner shark as Carcharias brevipinna in 1839. Shortly thereafter, this shark went through a series of name changes including Squalus brevipinna, Aprionodon brevipinna, and finally the currently valid name Carcharhinus brevipinna. The genus name Carcharhinus is derived from the Greek "karcharos" = sharpen and "rhinos" = nose. Synonyms referring to this shark in past scientific literature include Isogomphodon maculipinnis Poey 1865, Carcharhinus maculipinnis Poey 1865, Uranga nasuta Whitley 1943, Longmania calamaria Whitely 1944, Carcharinus johnsoni Smith 1951, Aprionodon caparti Poll 1951, and Carcharhinus johnsoni Smith 1951. It is also often confused with blacktip shark, Carcharhinus limbatus, due to similar characteristics.
Prepared by: Cathleen Bester