Blacktip SharkCarcharhinus limbatus
This medium sized, stocky shark is a dark grey-blue to brown on top with white underneath, and has its name-sake black tipped fins. They prefer to hunt schooling fish, often swimming quickly through a school and snapping up prey, and even breaching the water surface because of their momentum. They are generally timid sharks, but because they inhabit shallower waters (less than 100 ft), encounters with humans while they are hunting result in bites and other wounds (but no recorded fatalities).
Order - Carcharhiniformes
Family - Carcharhinidae
Genus - Carcharhinus
Species - limbatus
The blacktip shark gets its name from its distinctive black markings on the tips of its fins. It is also known as blackfin (Guam, Micronesia, Trinidad and Tobago), black-tipped (Papua New Guinea), small blacktip (Cuba, Leeward Islands), and spot-fin ground shark (UK).
Importance to HumansThe blacktip shark is a targeted species in a number of commercial fisheries, including the longline fishery off the southeast coast of the U.S. where it comprises about 7% of the catch. It is also regularly captured in fixed bottom nets and in shrimp trawls. The meat is used for fish meal or sold in local markets for human consumption. The fins are sold to Asian markets. The hides have also been used for leather.
Blacktip sharks are sometimes caught by sportfishers off Florida, the Caribbean islands, and South Africa. They are reported to give a good fight, often leaping out of the water. According to the International Game Fish Association (IGFA) a record size blacktip shark, caught in the Bahamas on rod and reel weighed 82 lbs.
Groups of blacktip sharks are regularly observed at recreational shark feeding dives in the Caribbean where they mix in with Caribbean reef sharks, Carcharhinus perezi.
Danger to HumansThe International Shark Attack File (ISAF) indicates that blacktip sharks are historically responsible for 28 unprovoked attacks on humans around the world. Attacks were reported in the United States (Florida, South Carolina, North Carolina, Virginia, and Alabama), the Caribbean (Bahamas and British Virgin Islands), and South Africa. None of these attacks ended in fatality, but commonly resulted in relatively minor bite wounds. Blacktip sharks are responsible for roughly 16% of the attacks that occur in Florida waters, often striking surfers.
The blacktip shark is currently managed by the National Marine Fisheries Service as a large coastal species in the Atlantic shark fishery. U.S. Catch rates have fluctuated over recent years, but reached a peak in commercial landings in 2000 in the U.S. southeast Atlantic shark fishery. The majority of the catch has been of adult sharks above their minimum reproductive size, which is a good indicator that this species may currently be managed in a sustainable fashion.
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 DistributionBlacktip sharks are cosmopolitan in tropical to subtropical coastal, shelf, and island waters. In the Atlantic during their seasonal migration they range from Nova Scotia to Brazil, but their center of abundance is in the Gulf of Mexico and Caribbean Sea. They occur throughout the Mediterranean and along the central West coast of Africa. In the Pacific they range from Southern California to Peru, including the Sea of Cortez. They occur at the Galapagos Islands, Hawaii, Tahiti, and other South Pacific Islands, to the North coast of Australia. In the Indian Ocean they range from South Africa and Madagascar up to the Red Sea, Persian Gulf, throughout India's coast, and east to the coast of China.
The blacktip shark inhabits inshore and offshore waters, but is not a truly pelagic species. They are often seen nearshore around river mouths, bays, mangrove swamps, and in other estuaries, though they do not penetrate far into freshwater. They can be found offshore and over deep waters near coral reef dropoffs, but primarily stay in the upper 100 feet (30 m) of the water column.
1. First, second dorsal fins, pectoral fins, and lower lobe of caudal fin black-tipped
(black markings may fade in adults; may be indistinct in juveniles)
2. Anal fin is white
3. First dorsal fin has a short free rear tip
4. The first dorsal fin originates slightly over or behind insertion point of pectoral fins along inner margin
5. The second dorsal fin originates over or slightly in front of the anal fin origin
Blacktip sharks are stout-bodied with a moderately long and pointed snout. They lack an interdorsal ridge. The first dorsal fin, positioned slightly posterior to the pectoral fin insertion, is high and has a narrowly pointed apex. The pectoral fins are fairly large and pointed. There is no interdorsal ridge on this species.
This shark may be easily confused with the spinner shark (C. brevipinna) which has a longer snout, smaller eyes and unmarked pelvic fins but dark tips to the anal fins.
The blacktip shark is dark gray/blue to brown above, and white below with a distinct white band across the flank. The black tips found on the pectoral fins, first and second dorsals, pelvic fins, and lower caudal lobe are very apparent, though they tend to fade with age. The blacktip does not usually have black tips on its anal fin. The similar-looking spinner shark (Carcharhinus brevipinna) does usually develop a black tip on its anal fin several months after birth.
The upper and lower jaw teeth of blacktip sharks are quite similar in shape, being moderately long, erect, and narrowly pointed with a broad base. The upper jaw teeth are more coarsely serrated along the cusp and crown than are the lower teeth which have fine serrations and tend to curve inwards. The teeth count is 15:2:15 in the upper jaw and 15:1:15 in the lower jaw.
Size, Age, and Growth
The maximum reported length of the blacktip shark is 8.4 feet (255 cm). Size at birth is 15-28 inches (38-72 cm). Average adult size is around 4.9 feet (150 cm), weighing about 40 lbs. (18 kg). Age at maturity is 4-5 years for males, and 6-7 years for females. The maximum age of blacktips is thought to be at least 12 years.
In waters off the southeastern U.S., the length at maturity is 4.8 feet (145 cm) total length (TL) for males corresponding to a weight of approximately 43 pounds (19.5 kg) and 5.2 feet (156 cm) TL for females corresponding to a weight of approximately 55 pounds (25 kg) (source: Castro 1996).
The blacktip shark primarily feeds on small schooling fishes such as herring, sardines, menhaden, mullet, and anchovies, but also eats many other bony fishes including catfishes, groupers, jacks, snook, porgies, grunts, croakers, flatfishes, triggerfish, and porcupine fish. They are also known to consume some elasmobranch species including dogfish, sharpnose sharks, young dusky sharks, skates, and stingrays. Crustaceans and squids are also occasionally taken.
Blacktips, as well as their close relative the spinner shark, are known to breach out of the water while feeding, sometimes spinning up to three or four times around their axis. This behavior is thought to facilitate the sharks' predatory success while feeding on schools of fish near the surface. The sharks vertically attack the school at high speed, snapping at the fish as they pass through it. The momentum then carries them through the ocean's surface.Reproduction
Development in the blacktip is viviparous, meaning they give birth to live, free-swimming young like others in the carcharhinid family. Males reach sexual maturity between 4.4 and 5.9 feet (135-180 cm). Females reach maturity at 3.9-6.3 feet (120-190 cm). Gestation last 10-12 months, and they give birth in late spring and early summer to 1-10 pups. Females give birth in inshore estuarine nursery grounds where the young remain for the first years of their lives.
Adult blacktip sharks do not have any common natural predators. Like other members of this shark family, however, the young are likely to be at risk of predation by larger sharks.
External parasites found on the body of the blacktip shark include the copepods Pandarus sinuatus andPandarus smithii
The blacktip shark was first described by Valenciennes in Muller & Henle (1839) as Carcharias (Prionodon) limbatus. It has also appeared in the literature as Carcharias (Prionodon) pleurotaenia, Carcharias microps, Carcharias (Prionodon) muelleri, Carcharias maculipinna, Carcharias ehrenbergi, Carcharias aethlorus, Gymnorrhinus abbreviatus, Carcharias phorcys, and Carcharhinus natator. The currently valid scientific name is Carcharhinus limbatus (Müller and Henle 1839). The genus name Carcharhinus is derived from the Greek "karcharos" = sharpen and "rhinos" = nose. The species name "limbatus" originates from Latin, meaning bordered in reference to the black markings on its fins.
Prepared by: Tobey Curtis