Ginglymostoma cirratum, the nurse shark, resides in coastal waters in the Pacific and Atlantic Oceans. In the Pacific Ocean, nurse sharks are found in waters off. Ginglymostoma cirratum. These bottom dwelling sharks are usually yellowish-tan to dark brown and, as adults, average around to 8 feet. Reference for: Ginglymostoma cirratum. Source: NODC Taxonomic Code, database (version ). Acquired: Notes: Reference for: Ginglymostoma cirratum.
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These bottom dwelling sharks are usually yellowish-tan to dark brown and, as adults, average around 7.
They are nocturnal, scouting the sea bottom for crustaceans, mollusks and stingrays during the night before returning to their preferred cave or crevice where they will often lay together in groups to sleep during the day Compagno et al. Nurse sharks are not aggressive, but there are attacks on record, that are usually the result of human provocation ISAF Historically, nurse sharks were targetted for their liver oil and for their skin which yields high quality leather Compagno et al.
At present, there is not a commercial fishery for this species. Regionally, Nurse sharks are still marketed for their fins, meat, and skin, particularly in Panama, Brazil, Venezuela, and the Caribbean.
In other areas, nurse sharks are caught and killed by fishermen as they are considered a nuisance animal that takes bait intended for other species. In the Lesser Antilles, where nurse sharks often raid fish traps, they are considered a pest. In the United States commercial fishery, they are often caught as by-catch but are released alive Rose et al.
Nurse sharks are not generally aggressive and usually swim away when approached. However, some unprovoked attacks on swimmers and divers have been reported. If disturbed, they giinglymostoma bite with a powerful, vice-like grip capable of inflicting serious injury.
In some instances, the jaws lock and can only be released using surgical instruments. The frequency of bites has increased in recent years as a result of ecotourism feeding operations ISAF It is not an endangered species; however, its abundance in the littoral waters of Florida has decreased in past decades. The presence of this species in areas with constant anthropogenic activity make it susceptible ginglymostomx disturbance.
Because of its relatively docile nature, ginglmyostoma with, handling, and feeding nurse sharks is popular with ecotourism operators. In the Eastern Pacific, populations have declined precipitously. In the southern-most ranges of Brazil, the nurse shark is considered locally extinct. The effects of interactions with humans in coastal waters are unknown, but nursery areas are now limited to remote regions, suggesting an association.
Identification and protection of these areas, coupled with further research on the biology of the nurse shark, is needed to provide effective conservation measures Rosa et al.
The IUCN is a global union of states, governmental agencies, and non-governmental organizations in a partnership that assesses the conservation status of species. The nurse shark is common in the Atlantic, in the coastal tropical and sub-tropical waters.
The Eastern Pacific population has recently been described as a separate species Ginglymostoma unami. Some individuals have been reported in the Gulf of Gascogne in southwest France, as well. This species is locally very common in shallow waters throughout the West Indies, south Florida gonglymostoma the Florida Keys. The nurse shark is a nocturnal animal that rests on sandy bottoms or in shallow-water caves and rock crevices during the day. They occasionally occur in cirrstum of up to 40 ginglymosotma, where they can ginglmyostoma seen lying close together, sometimes piled upon one another Compagno et ginglymosroma.
Nurse sharks are active during the night, often swimming near the bottom or clambering across the sea floor, using their muscular pectoral fins as limbs Gihglymostoma et al. Large juveniles and adults are usually found around deeper reefs and rocky areas at depths of meters ft during the daytime moving into shallower waters of less than 20 meters 65 ft after dark.
Juveniles are generally found around shallow coral reefs, grass flats or mangrove islands in meters ft of water Castro Nurse sharks show a strong preference for specific resting sites, repeatedly returning to the same caves and crevices after nocturnal activity Compagno First dorsal fin originates well behind the pectoral fins and over or behind the origin of the pelvic fins.
Distinctive Features Nurse sharks have two spineless, rounded dorsal fins with the first larger than second, and one anal fin.
Ginglymostoma cirratum – Discover Fishes
The origin of the first dorsal fin is over the origin of the pelvic fin. The sub-terminal mouth is well in front of the eyes, the spiracles ginglykostoma minute, and moderately long barbels reach the mouth Compagno et al.
Nasoral grooves are present, but there is no perinasal groove.
Coloration Adult nurse sharks generally range from light tan ginylymostoma dark brown in color. Juveniles up to 55 cm 22 in have small black spots, cirgatum an area of lighter pigmentation surrounding each spot, covering the entire body. These are bands of lighter and darker pigmentation along the dorsal surface. In a tank experiment small nurse sharks, covered for just a few minutes became considerably lighter than individuals exposed to full sunlight Castro Unusually pigmented individuals e.
Dentition Nurse sharks possess an independent dentition, the simplest type of tooth arrangement found in sharks where there is no overlap between teeth. This allows forward movement of replacement teeth that is independent of adjacent teeth in the jaw. Replacement rates among juveniles are generally faster than for adults.
Tooth replacement occurs faster in summer, when water temperatures are higher Luer et al. Size, Age, and Growth Size at maturity for females is cirratumm cms and about cms for males. Size at birth is in the cms ginglymoshoma range. Age at maturity for females is years and for males years. The maximum recorded size of a nurse shark is cm Rosa et al. Food Habits The nurse shark is gingpymostoma nocturnal predator glnglymostoma feeds mainly on fish, stingrays, mollusks octopi, squids and clams and crustaceans.
Algae and corals are occasionally found in their stomachs, as well. The nurse shark has a small mouth but its large pharynx allows it to suck in food items efficiently. This system probably allows the species to prey on small fish that are resting at night, but that are too active for the sluggish nurse shark to catch during the day. Heavy-shelled conchs are flipped over, and the snail extracted by use of suction and teeth Rosa et al.
Description & Behavior
Young nurse sharks have been observed resting with their snouts pointed upwards and their bodies supported off the bottom on their pectoral fins. Some suggest this posture may provide a false shelter for crabs and small fishes that the shark can ambush and eat Compagno et al. The nurse shark is an ovoviviparous species. The embryo has its own yolk sac, which is absorbed during development, and there is no placental nourishment from the mother.
The nurse shark has a biennial reproductive cycle. After mating, gestation takes five to six months Compagno et al. Each pup measures cm It takes another eighteen months for the ovaries to produce enough mature eggs for the next breeding cycle. In the waters of the Florida Keys and the Dry Tortugas archipelagos, the reproductive behavior of the nurse shark has been regularly observed and studied.
Its copulatory behavior is among the best documented among sharks.
Males approach females that are resting on the sea floor or are swimming just above it. A large number of males generally try to mate with a single female, often leading to females bearing numerous scars and bruises from male bites. Females frequently try to avoid contact with males by swimming in very shallow water, where they can bury their pectoral fins in the sand Castro Predators There are no species that regularly prey on nurse sharks.
However, some larger sharks are known to occasionally feed on them. Remains of nurse sharks have been found in lemon shark and tiger shark stomachs, and attacks on nurse sharks by bull sharks and great hammerhead sharks have been observed Castro Parasites Nematodes have been observed in the gills of nurse sharks in captivity at the New York Aquarium, U.
The nurse shark was first described by Bonnaterreas Squalus cirratus. The current scientific combination, Ginglymostoma cirratum was first assigned by Muller and Henle in The species name cirratum is translated from Latin as curl.
Similarities in the reproductive cycle and molecular phylogenetic data indicate a close relationship between the nurse shark family Ginglymostomatidae and the whale shark family Rhincodontidae. The biology of the nurse shark, Ginglymostoma cirratum, off the Florida east coast and the Bahama Islands. Sharks of the world. An annotated and illustrated catalogue of cirrafum species known to date.
Cidratum Field Guide to the Sharks of the World. Harper Collins Publishers Ltd. Copeia, 1 Discover Fishes Ginglymostoma cirratum. Nurse Shark Nurse shark.
IUCN Red List of Threatened Species
Other common names used to refer to this shark include: Danger cireatum Humans Nurse sharks are not generally aggressive and usually swim away when approached. Geographical Distribution World distribution for the nurse shark.
Habitat The nurse shark is a nocturnal animal that rests on sandy bottoms or in shallow-water caves and rock crevices during the day.
Distinguishing Cirrtaum Nurse shark Ginglymostoma cirratum. Mouth near tip of snout has nasal barbels on either side 2. First and second dorsal and anal fins are broadly rounded 3. The second dorsal fin is slightly smaller than the first 4. There is no distinct lower lobe on the caudal cirratim 5. Eyes are very small 6. First dorsal fin ginglymoetoma well behind the pectoral fins and over or behind the origin of the pelvic fins Biology Distinctive Features Nurse sharks have two spineless, rounded dorsal fins with the first larger than second, and one anal fin.
Independent dentition of the nurse shark. Reproduction Egg cases from nurse shark. Taxonomy The nurse shark was first described by Bonnaterreas Squalus cirratus.