Bignose shark
Encyclopedia
The bignose shark is a species
of requiem shark
, family
Carcharhinidae. Distributed worldwide in tropical and subtropical waters, this migratory
shark frequents deep waters around the edges of the continental shelf
. It is typically found at depths of 90–430 m (295.3–1,410.8 ft), though at night it may move towards the surface or into shallower water. The bignose shark is plain-colored and grows to at least 2.7–2.8 m (8.9–9.2 ft) in length. It has a long, broad snout with prominent nasal skin flaps, and tall, triangular upper teeth. Its pectoral fins are long and almost straight, and there is a ridge on its back between the two dorsal fin
s.
Hunting close to the sea floor, the bignose shark feeds on bony and cartilaginous fishes, and cephalopod
s. It is viviparous, meaning that the embryo
s are sustained to term via a placenta
l connection. Females bear litters of 3–15 pups after a 10 month gestation period
. Despite its size, this shark lives too deep to pose much danger to humans. It is caught incidentally
by commercial fisheries
in many parts of its range; the meat, fins
, skin
, liver oil
, and offal
may be used. The International Union for Conservation of Nature (IUCN) presently lacks enough information to assess the global conservation status of this species. However, the various fishing pressures within its range are cause for concern given its slow reproductive rate, and it may have already declined in the northwestern Atlantic and elsewhere.
described
the bignose shark as Eulamia altima in a 1950 issue of the scientific journal
American Museum Novitates. Later authors have regarded the genus Eulamia as a synonym
of Carcharhinus. The specific epithet altimus is derived from the Latin
altus ("deep"), and refers to the shark's deepwater habits. The type specimen is an immature female 1.3 m (4.3 ft) long, caught off Cosgrove Reef in the Florida Keys
on April 2, 1947. An alternate common name
for this species is Knopp's shark, originally used by Florida
fishery
workers since before the species was described.
Phylogenetic studies published by Jack Garrick in 1982 and Leonard Compagno
in 1988, based on morphology
, placed the bignose shark in the "obscurus group" of Carcharhinus, centered on the dusky shark
(C. obscurus) and the Galapagos shark
(C. galapagensis). The group consists of large, triangular-toothed sharks with a ridge between the dorsal fins. Gavin Naylor's 1992 study, based on allozyme
sequences, upheld and further resolved this "ridge-backed" group. The bignose shark was found to be the sister species of the sandbar shark
(C. plumbeus), with the two forming one of the group's two branches.
, it occurs from Delaware Bay
to Brazil
, in the Mediterranean Sea
, and off West Africa
. In the Indian Ocean
, it is known from South Africa
and Madagascar
, the Red Sea
, India
, and the Maldives
. In the Pacific Ocean
, it has been recorded from China
to Australia
, around Hawaii
, and from the Gulf of California
to Ecuador
. It is reportedly common off Florida, the Bahamas, and the West Indies, and rare off Brazil and in the Mediterranean.
The bignose shark is found near the edge of the continental shelf
and over the upper continental slope, generally swimming close to the sea floor at depths of 90–430 m (295.3–1,410.8 ft). Young sharks may venture into water as shallow as 25 m (82 ft). Nighttime captures of this species from close to the surface suggest that it may perform a diel vertical migration
, moving from deep water upwards or toward the coast at night. In the northwestern Atlantic, the bignose shark conducts a poorly documented seasonal migration
, spending summer off the US East Coast
and winter in the Gulf of Mexico
and the Caribbean Sea
. Individual sharks have been recorded traveling distances between 1600 and 3200 km (994.2 and 1,988.4 mi).
s (protective third eyelids). The mouth is broadly curved and lacks obvious furrows at the corners. The upper teeth number 14–16 rows on either side and have tall, broad, triangular cusps with serrated edges; they are erect at the jaw center and become increasingly oblique towards the sides. The lower teeth number 14–15 rows on either side and have narrow, erect cusps with extremely fine serrations. The five pairs of gill slit
s are moderately long.
The long and wide pectoral fins have pointed tips and nearly straight margins. The first dorsal fin
originates roughly over the rear of the pectoral fin bases; it is fairly tall and falcate (sickle-shaped), with a blunt apex and a long free rear tip. The second dorsal fin is relatively large with a short free rear tip, and is positioned slightly ahead of the anal fin. A high midline ridge is present between the dorsal fins. The caudal peduncle has a crescent-shaped notch at the origin of the upper caudal fin margin. The caudal fin has a large lower lobe and a strong ventral notch near the tip of the upper lobe. The dermal denticles are closely spaced but non-overlapping, such as that the skin shows between them; each is oval with three horizontal ridges leading to marginal teeth. The coloration is gray to bronze above, with a faint pale stripe on the flank, and white below; sometimes there is a green sheen along the gills. The tips of the fins (except for the pelvic fins) are darker; this is most obvious in young sharks. Males and females grow to at least 2.7 m (8.9 ft) and 2.8 m (9.2 ft) long respectively; this species possibly reaches 3 m (9.8 ft) in length. The maximum weight on record is 168 kg (370.4 lb).
The bignose shark feeds mainly on bottom-dwelling bony fishes (including lizardfishes, croaker
s, flatfish
es, and batfish
es), cartilaginous fishes (including Squalus dogfish
es, Holohalaelurus
catshark
s, Dasyatis
stingray
s, and chimaera
s), and cephalopod
s. In turn, juveniles may potentially fall prey to larger sharks. Like other requiem sharks, this species is viviparous: when the developing embryo
s exhaust their supply of yolk, the depleted yolk sac
is converted into a placenta
l connection through which the mother delivers nourishment. Females bear litters of 3–15 pups, with 7 being typical, following a gestation period
of approximately 10 months. A single litter may be fathered by two or more males. Birthing has been reported to occur in August and September in the Mediterranean, and in September and October off Madagascar. The newborns measure 70–90 cm (27.6–35.4 in) long. Males and females mature sexually
at around 2.2 and 2.3 m (7.2 and 7.5 ft) long respectively. The average age of reproductively active individuals is 21 years.
of gillnet
, bottom trawl, and deep-set pelagic longline fisheries (particularly those targeting tuna
) in many parts of its range. It is regularly taken in Cuba
n waters and used to produce liver oil
, shagreen
, and fishmeal. Elsewhere, such as in Southeast Asia
, the meat is consumed and the fins shipped to East Asia
for shark fin soup
. The bignose shark is not utilized commercially in United States
, where it is listed as Prohibited Species under the 2007 Fishery Management Plan (FMP) for Atlantic tunas, swordfish and sharks, or in Australia
.
The International Union for Conservation of Nature (IUCN) has listed the bignose shark as Data Deficient
overall, due to inadequate population and fishery monitoring. The species is considered to be of concern however, given that it is slow-reproducing and faces widespread heavy fishing pressure. There is evidence that its numbers have recently declined in the Maldives. Furthermore, most bignose shark bycatch occurs in international waters
, where a single stock
may be affected by multiple fisheries. It is listed as a "highly migratory species" under the 1995 UN Agreement on the Conservation and Management of Straddling Fish Stocks and Highly Migratory Fish Stocks (UNFSA), but thus far this has not led to significant conservation measures. Regionally, the IUCN has assessed the bignose shark as Near Threatened
in the northwestern Atlantic. Though specific data is lacking, it is suspected to have declined there because it is commonly misidentified as the sandbar shark, and thus the known decline in sandbar shark numbers resulting from US longline fishing may represent a decline in bignose shark numbers as well. This species has been assessed as Least Concern
in Australian waters, where it faces no significant threats.
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
of requiem shark
Requiem shark
Requiem sharks are a family, Carcharhinidae, of sharks in the order Carcharhiniformes, containing migratory, live-bearing sharks of warm seas such as the tiger shark, the blue shark, the bull shark, and the milk shark.The name may be related to the French word for shark, "requin", itself of...
, family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
Carcharhinidae. Distributed worldwide in tropical and subtropical waters, this migratory
Fish migration
Many types of fish migrate on a regular basis, on time scales ranging from daily to annually or longer, and over distances ranging from a few metres to thousands of kilometres...
shark frequents deep waters around the edges of the continental shelf
Continental shelf
The continental shelf is the extended perimeter of each continent and associated coastal plain. Much of the shelf was exposed during glacial periods, but is now submerged under relatively shallow seas and gulfs, and was similarly submerged during other interglacial periods. The continental margin,...
. It is typically found at depths of 90–430 m (295.3–1,410.8 ft), though at night it may move towards the surface or into shallower water. The bignose shark is plain-colored and grows to at least 2.7–2.8 m (8.9–9.2 ft) in length. It has a long, broad snout with prominent nasal skin flaps, and tall, triangular upper teeth. Its pectoral fins are long and almost straight, and there is a ridge on its back between the two dorsal fin
Dorsal fin
A dorsal fin is a fin located on the backs of various unrelated marine and freshwater vertebrates, including most fishes, marine mammals , and the ichthyosaurs...
s.
Hunting close to the sea floor, the bignose shark feeds on bony and cartilaginous fishes, and cephalopod
Cephalopod
A cephalopod is any member of the molluscan class Cephalopoda . These exclusively marine animals are characterized by bilateral body symmetry, a prominent head, and a set of arms or tentacles modified from the primitive molluscan foot...
s. It is viviparous, meaning that the embryo
Embryo
An embryo is a multicellular diploid eukaryote in its earliest stage of development, from the time of first cell division until birth, hatching, or germination...
s are sustained to term via a placenta
Placenta
The placenta is an organ that connects the developing fetus to the uterine wall to allow nutrient uptake, waste elimination, and gas exchange via the mother's blood supply. "True" placentas are a defining characteristic of eutherian or "placental" mammals, but are also found in some snakes and...
l connection. Females bear litters of 3–15 pups after a 10 month gestation period
Gestation period
For mammals the gestation period is the time in which a fetus develops, beginning with fertilization and ending at birth. The duration of this period varies between species.-Duration:...
. Despite its size, this shark lives too deep to pose much danger to humans. It is caught incidentally
Bycatch
The term “bycatch” is usually used for fish caught unintentionally in a fishery while intending to catch other fish. It may however also indicate untargeted catch in other forms of animal harvesting or collecting...
by commercial fisheries
Commercial fishing
Commercial fishing is the activity of catching fish and other seafood for commercial profit, mostly from wild fisheries. It provides a large quantity of food to many countries around the world, but those who practice it as an industry must often pursue fish far into the ocean under adverse conditions...
in many parts of its range; the meat, fins
Shark fin soup
Shark fin soup is a popular soup item of Chinese cuisine usually served at special occasions such as weddings and banquets, or as a luxury item in Chinese culture. The shark fins provide texture while the taste comes from the other soup ingredients.There is controversy over the practice of shark...
, skin
Shagreen
Shagreen is a type of leather or rawhide consisting of rough untanned skin, formerly made from a horse's back or that of an onager . Shagreen is now commonly made of the skins of sharks and rays....
, liver oil
Shark liver oil
Shark liver oil is obtained from sharks that are caught for food purposes and are living in cold, deep oceans. The liver oil from sharks has been used by fishermen for centuries as a folk remedy for general health...
, and offal
Offal
Offal , also called, especially in the United States, variety meats or organ meats, refers to the internal organs and entrails of a butchered animal. The word does not refer to a particular list of edible organs, which varies by culture and region, but includes most internal organs other than...
may be used. The International Union for Conservation of Nature (IUCN) presently lacks enough information to assess the global conservation status of this species. However, the various fishing pressures within its range are cause for concern given its slow reproductive rate, and it may have already declined in the northwestern Atlantic and elsewhere.
Taxonomy and phylogeny
Shark expert Stewart SpringerStewart Springer
Stewart Springer, was a world renowned expert on shark behavior, classification , and distribution of shark populations. There are more than 35 species of sharks, skates, rays, and other animals either classified originally by him or named after him.-Education:Springer was a field naturalist,...
described
Species description
A species description or type description is a formal description of a newly discovered species, usually in the form of a scientific paper. Its purpose is to give a clear description of a new species of organism and explain how it differs from species which have been described previously, or are...
the bignose shark as Eulamia altima in a 1950 issue of the scientific journal
Scientific journal
In academic publishing, a scientific journal is a periodical publication intended to further the progress of science, usually by reporting new research. There are thousands of scientific journals in publication, and many more have been published at various points in the past...
American Museum Novitates. Later authors have regarded the genus Eulamia as a synonym
Synonym (taxonomy)
In scientific nomenclature, a synonym is a scientific name that is or was used for a taxon of organisms that also goes by a different scientific name. For example, Linnaeus was the first to give a scientific name to the Norway spruce, which he called Pinus abies...
of Carcharhinus. The specific epithet altimus is derived from the Latin
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...
altus ("deep"), and refers to the shark's deepwater habits. The type specimen is an immature female 1.3 m (4.3 ft) long, caught off Cosgrove Reef in the Florida Keys
Florida Keys
The Florida Keys are a coral archipelago in southeast United States. They begin at the southeastern tip of the Florida peninsula, about south of Miami, and extend in a gentle arc south-southwest and then westward to Key West, the westernmost of the inhabited islands, and on to the uninhabited Dry...
on April 2, 1947. An alternate common name
Common name
A common name of a taxon or organism is a name in general use within a community; it is often contrasted with the scientific name for the same organism...
for this species is Knopp's shark, originally used by Florida
Florida
Florida is a state in the southeastern United States, located on the nation's Atlantic and Gulf coasts. It is bordered to the west by the Gulf of Mexico, to the north by Alabama and Georgia and to the east by the Atlantic Ocean. With a population of 18,801,310 as measured by the 2010 census, it...
fishery
Fishery
Generally, a fishery is an entity engaged in raising or harvesting fish which is determined by some authority to be a fishery. According to the FAO, a fishery is typically defined in terms of the "people involved, species or type of fish, area of water or seabed, method of fishing, class of boats,...
workers since before the species was described.
Phylogenetic studies published by Jack Garrick in 1982 and Leonard Compagno
Leonard Compagno
Leonard Joseph Victor Compagno is an international authority on shark taxonomy and the author of many scientific papers and books on the subject, best known of which is his 1984 catalogue of shark species produced for the Food and Agriculture Organization of the United Nations.-Career:*Ph.D,...
in 1988, based on morphology
Morphology (biology)
In biology, morphology is a branch of bioscience dealing with the study of the form and structure of organisms and their specific structural features....
, placed the bignose shark in the "obscurus group" of Carcharhinus, centered on the dusky shark
Dusky shark
The dusky shark is a species of requiem shark, family Carcharhinidae, occurring in tropical and warm-temperate continental seas worldwide. A generalist apex predator, the dusky shark can be found from the coast to the outer continental shelf and adjacent pelagic waters, and has been recorded from...
(C. obscurus) and the Galapagos shark
Galapagos shark
The Galapagos shark is a species of requiem shark, family Carcharhinidae, found worldwide. This species favors clear reef environments around oceanic islands, where it is often the most abundant shark species...
(C. galapagensis). The group consists of large, triangular-toothed sharks with a ridge between the dorsal fins. Gavin Naylor's 1992 study, based on allozyme
Allozyme
Variant forms of an enzyme that are coded by different alleles at the same locus are called allozymes. These are opposed to isozymes, which are enzymes that perform the same function, but which are coded by genes located at different loci....
sequences, upheld and further resolved this "ridge-backed" group. The bignose shark was found to be the sister species of the sandbar shark
Sandbar shark
The sandbar shark, Carcharhinus plumbeus, is a species of requiem shark, family Carcharhinidae, native to the Atlantic Ocean and the Indo-Pacific. It is distinguishable by its very high first dorsal fin and inter-dorsal ridge....
(C. plumbeus), with the two forming one of the group's two branches.
Distribution and habitat
Patchy records from around the world indicate that the bignose shark probably has a circumglobal distribution in tropical and subtropical waters. In the Atlantic OceanAtlantic Ocean
The Atlantic Ocean is the second-largest of the world's oceanic divisions. With a total area of about , it covers approximately 20% of the Earth's surface and about 26% of its water surface area...
, it occurs from Delaware Bay
Delaware Bay
Delaware Bay is a major estuary outlet of the Delaware River on the Northeast seaboard of the United States whose fresh water mixes for many miles with the waters of the Atlantic Ocean. It is in area. The bay is bordered by the State of New Jersey and the State of Delaware...
to Brazil
Brazil
Brazil , officially the Federative Republic of Brazil , is the largest country in South America. It is the world's fifth largest country, both by geographical area and by population with over 192 million people...
, in the Mediterranean Sea
Mediterranean Sea
The Mediterranean Sea is a sea connected to the Atlantic Ocean surrounded by the Mediterranean region and almost completely enclosed by land: on the north by Anatolia and Europe, on the south by North Africa, and on the east by the Levant...
, and off West Africa
West Africa
West Africa or Western Africa is the westernmost region of the African continent. Geopolitically, the UN definition of Western Africa includes the following 16 countries and an area of approximately 5 million square km:-Flags of West Africa:...
. In the Indian Ocean
Indian Ocean
The Indian Ocean is the third largest of the world's oceanic divisions, covering approximately 20% of the water on the Earth's surface. It is bounded on the north by the Indian Subcontinent and Arabian Peninsula ; on the west by eastern Africa; on the east by Indochina, the Sunda Islands, and...
, it is known from South Africa
South Africa
The Republic of South Africa is a country in southern Africa. Located at the southern tip of Africa, it is divided into nine provinces, with of coastline on the Atlantic and Indian oceans...
and Madagascar
Madagascar
The Republic of Madagascar is an island country located in the Indian Ocean off the southeastern coast of Africa...
, the Red Sea
Red Sea
The Red Sea is a seawater inlet of the Indian Ocean, lying between Africa and Asia. The connection to the ocean is in the south through the Bab el Mandeb strait and the Gulf of Aden. In the north, there is the Sinai Peninsula, the Gulf of Aqaba, and the Gulf of Suez...
, India
India
India , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world...
, and the Maldives
Maldives
The Maldives , , officially Republic of Maldives , also referred to as the Maldive Islands, is an island nation in the Indian Ocean formed by a double chain of twenty-six atolls oriented north-south off India's Lakshadweep islands, between Minicoy Island and...
. In the Pacific Ocean
Pacific Ocean
The Pacific Ocean is the largest of the Earth's oceanic divisions. It extends from the Arctic in the north to the Southern Ocean in the south, bounded by Asia and Australia in the west, and the Americas in the east.At 165.2 million square kilometres in area, this largest division of the World...
, it has been recorded from China
China
Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...
to Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
, around Hawaii
Hawaii
Hawaii is the newest of the 50 U.S. states , and is the only U.S. state made up entirely of islands. It is the northernmost island group in Polynesia, occupying most of an archipelago in the central Pacific Ocean, southwest of the continental United States, southeast of Japan, and northeast of...
, and from the Gulf of California
Gulf of California
The Gulf of California is a body of water that separates the Baja California Peninsula from the Mexican mainland...
to Ecuador
Ecuador
Ecuador , officially the Republic of Ecuador is a representative democratic republic in South America, bordered by Colombia on the north, Peru on the east and south, and by the Pacific Ocean to the west. It is one of only two countries in South America, along with Chile, that do not have a border...
. It is reportedly common off Florida, the Bahamas, and the West Indies, and rare off Brazil and in the Mediterranean.
The bignose shark is found near the edge of the continental shelf
Continental shelf
The continental shelf is the extended perimeter of each continent and associated coastal plain. Much of the shelf was exposed during glacial periods, but is now submerged under relatively shallow seas and gulfs, and was similarly submerged during other interglacial periods. The continental margin,...
and over the upper continental slope, generally swimming close to the sea floor at depths of 90–430 m (295.3–1,410.8 ft). Young sharks may venture into water as shallow as 25 m (82 ft). Nighttime captures of this species from close to the surface suggest that it may perform a diel vertical migration
Diel vertical migration
Diel vertical migration, also known as diurnal vertical migration, is a pattern of movement that some organisms living in the ocean and in lakes undertake each day. Usually organisms move up to the epipelagic zone at night and return to the mesopelagic zone of the oceans or to the hypolimnion zone...
, moving from deep water upwards or toward the coast at night. In the northwestern Atlantic, the bignose shark conducts a poorly documented seasonal migration
Fish migration
Many types of fish migrate on a regular basis, on time scales ranging from daily to annually or longer, and over distances ranging from a few metres to thousands of kilometres...
, spending summer off the US East Coast
East Coast of the United States
The East Coast of the United States, also known as the Eastern Seaboard, refers to the easternmost coastal states in the United States, which touch the Atlantic Ocean and stretch up to Canada. The term includes the U.S...
and winter in the Gulf of Mexico
Gulf of Mexico
The Gulf of Mexico is a partially landlocked ocean basin largely surrounded by the North American continent and the island of Cuba. It is bounded on the northeast, north and northwest by the Gulf Coast of the United States, on the southwest and south by Mexico, and on the southeast by Cuba. In...
and the Caribbean Sea
Caribbean Sea
The Caribbean Sea is a sea of the Atlantic Ocean located in the tropics of the Western hemisphere. It is bounded by Mexico and Central America to the west and southwest, to the north by the Greater Antilles, and to the east by the Lesser Antilles....
. Individual sharks have been recorded traveling distances between 1600 and 3200 km (994.2 and 1,988.4 mi).
Description
Rather heavily built, the bignose shark has a long, broad, and blunt snout with the nostrils preceded by well-developed, triangular flaps of skin. The moderately large, circular eyes are equipped with nictitating membraneNictitating membrane
The nictitating membrane is a transparent or translucent third eyelid present in some animals that can be drawn across the eye for protection and to moisten it while maintaining visibility. Some reptiles, birds, and sharks have a full nictitating membrane; in many mammals, there is a small...
s (protective third eyelids). The mouth is broadly curved and lacks obvious furrows at the corners. The upper teeth number 14–16 rows on either side and have tall, broad, triangular cusps with serrated edges; they are erect at the jaw center and become increasingly oblique towards the sides. The lower teeth number 14–15 rows on either side and have narrow, erect cusps with extremely fine serrations. The five pairs of gill slit
Gill slit
Gill slits are individual openings to gills, i.e., multiple gill arches, which lack a single outer cover. Such gills are characteristic of Cartilaginous fish such as sharks, rays, sawfish, and guitarfish. Most of these have five pairs, but a few species have 6 or 7 pairs...
s are moderately long.
The long and wide pectoral fins have pointed tips and nearly straight margins. The first dorsal fin
Dorsal fin
A dorsal fin is a fin located on the backs of various unrelated marine and freshwater vertebrates, including most fishes, marine mammals , and the ichthyosaurs...
originates roughly over the rear of the pectoral fin bases; it is fairly tall and falcate (sickle-shaped), with a blunt apex and a long free rear tip. The second dorsal fin is relatively large with a short free rear tip, and is positioned slightly ahead of the anal fin. A high midline ridge is present between the dorsal fins. The caudal peduncle has a crescent-shaped notch at the origin of the upper caudal fin margin. The caudal fin has a large lower lobe and a strong ventral notch near the tip of the upper lobe. The dermal denticles are closely spaced but non-overlapping, such as that the skin shows between them; each is oval with three horizontal ridges leading to marginal teeth. The coloration is gray to bronze above, with a faint pale stripe on the flank, and white below; sometimes there is a green sheen along the gills. The tips of the fins (except for the pelvic fins) are darker; this is most obvious in young sharks. Males and females grow to at least 2.7 m (8.9 ft) and 2.8 m (9.2 ft) long respectively; this species possibly reaches 3 m (9.8 ft) in length. The maximum weight on record is 168 kg (370.4 lb).
Biology and ecology
Sciaenidae
Sciaenidae is a family of fish commonly called drums, croakers, or hardheads for the repetitive throbbing or drumming sounds they make...
s, flatfish
Flatfish
The flatfish are an order of ray-finned fish, also called the Heterosomata, sometimes classified as a suborder of Perciformes. In many species, both eyes lie on one side of the head, one or the other migrating through and around the head during development...
es, and batfish
Ogcocephalidae
Ogcocephalidae is a family of bottom-dwelling, specially adapted fish. They are sometimes referred to as batfishes or anglerfishes. They are found in deep, lightless waters of the Atlantic, Indian and western Pacific Oceans....
es), cartilaginous fishes (including Squalus dogfish
Squaliformes
Squaliformes is an order of sharks that includes about 97 species in seven families.Members of the order have two dorsal fins, which usually possess spines, no anal fin or nictitating membrane, and five gill slits. In most other respects, however, they are quite variable in form and size...
es, Holohalaelurus
Holohalaelurus
Holohalaelurus is a genus of catshark in the family Scyliorhinidae, commonly known as Izak catsharks or hallelujah sharks.-Species:* Holohalaelurus favus Human, 2006...
catshark
Catshark
Catsharks are ground sharks of the family Scyliorhinidae, with over 150 known species. While they are generally known as catsharks, many species are commonly called dogfish....
s, Dasyatis
Dasyatis
Dasyatis is a genus of stingray. The members of the genus Neotrygon were formerly included in Dasyatis.-Species:...
stingray
Stingray
The stingrays are a group of rays, which are cartilaginous fishes related to sharks. They are classified in the suborder Myliobatoidei of the order Myliobatiformes, and consist of eight families: Hexatrygonidae , Plesiobatidae , Urolophidae , Urotrygonidae , Dasyatidae , Potamotrygonidae The...
s, and chimaera
Chimaera
Chimaeras are cartilaginous fish in the order Chimaeriformes, known informally as ghost sharks, ratfish , spookfish , or rabbitfishes...
s), and cephalopod
Cephalopod
A cephalopod is any member of the molluscan class Cephalopoda . These exclusively marine animals are characterized by bilateral body symmetry, a prominent head, and a set of arms or tentacles modified from the primitive molluscan foot...
s. In turn, juveniles may potentially fall prey to larger sharks. Like other requiem sharks, this species is viviparous: when the developing embryo
Embryo
An embryo is a multicellular diploid eukaryote in its earliest stage of development, from the time of first cell division until birth, hatching, or germination...
s exhaust their supply of yolk, the depleted yolk sac
Yolk sac
The yolk sac is a membranous sac attached to an embryo, providing early nourishment in the form of yolk in bony fishes, sharks, reptiles, birds, and primitive mammals...
is converted into a placenta
Placenta
The placenta is an organ that connects the developing fetus to the uterine wall to allow nutrient uptake, waste elimination, and gas exchange via the mother's blood supply. "True" placentas are a defining characteristic of eutherian or "placental" mammals, but are also found in some snakes and...
l connection through which the mother delivers nourishment. Females bear litters of 3–15 pups, with 7 being typical, following a gestation period
Gestation period
For mammals the gestation period is the time in which a fetus develops, beginning with fertilization and ending at birth. The duration of this period varies between species.-Duration:...
of approximately 10 months. A single litter may be fathered by two or more males. Birthing has been reported to occur in August and September in the Mediterranean, and in September and October off Madagascar. The newborns measure 70–90 cm (27.6–35.4 in) long. Males and females mature sexually
Sexual maturity
Sexual maturity is the age or stage when an organism can reproduce. It is sometimes considered synonymous with adulthood, though the two are distinct...
at around 2.2 and 2.3 m (7.2 and 7.5 ft) long respectively. The average age of reproductively active individuals is 21 years.
Human interactions
While large enough to perhaps be dangerous, the bignose shark seldom comes into contact with humans due to its preference for deep water. This species is a bycatchBycatch
The term “bycatch” is usually used for fish caught unintentionally in a fishery while intending to catch other fish. It may however also indicate untargeted catch in other forms of animal harvesting or collecting...
of gillnet
Gillnet
Gillnetting is a common fishing method used by commercial and artisanal fishermen of all the oceans and in some freshwater and estuary areas. The gillnet also is used by fisheries scientists to monitor fish populations. Because gillnets can be so effective their use is closely monitored and...
, bottom trawl, and deep-set pelagic longline fisheries (particularly those targeting tuna
Tuna
Tuna is a salt water fish from the family Scombridae, mostly in the genus Thunnus. Tuna are fast swimmers, and some species are capable of speeds of . Unlike most fish, which have white flesh, the muscle tissue of tuna ranges from pink to dark red. The red coloration derives from myoglobin, an...
) in many parts of its range. It is regularly taken in Cuba
Cuba
The Republic of Cuba is an island nation in the Caribbean. The nation of Cuba consists of the main island of Cuba, the Isla de la Juventud, and several archipelagos. Havana is the largest city in Cuba and the country's capital. Santiago de Cuba is the second largest city...
n waters and used to produce liver oil
Shark liver oil
Shark liver oil is obtained from sharks that are caught for food purposes and are living in cold, deep oceans. The liver oil from sharks has been used by fishermen for centuries as a folk remedy for general health...
, shagreen
Shagreen
Shagreen is a type of leather or rawhide consisting of rough untanned skin, formerly made from a horse's back or that of an onager . Shagreen is now commonly made of the skins of sharks and rays....
, and fishmeal. Elsewhere, such as in Southeast Asia
Southeast Asia
Southeast Asia, South-East Asia, South East Asia or Southeastern Asia is a subregion of Asia, consisting of the countries that are geographically south of China, east of India, west of New Guinea and north of Australia. The region lies on the intersection of geological plates, with heavy seismic...
, the meat is consumed and the fins shipped to East Asia
East Asia
East Asia or Eastern Asia is a subregion of Asia that can be defined in either geographical or cultural terms...
for shark fin soup
Shark fin soup
Shark fin soup is a popular soup item of Chinese cuisine usually served at special occasions such as weddings and banquets, or as a luxury item in Chinese culture. The shark fins provide texture while the taste comes from the other soup ingredients.There is controversy over the practice of shark...
. The bignose shark is not utilized commercially in United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
, where it is listed as Prohibited Species under the 2007 Fishery Management Plan (FMP) for Atlantic tunas, swordfish and sharks, or in Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
.
The International Union for Conservation of Nature (IUCN) has listed the bignose shark as Data Deficient
Data Deficient
Data Deficient is a category applied by the IUCN, other agencies, and individuals to a species when the available information is not sufficient for a proper assessment of conservation status to be made...
overall, due to inadequate population and fishery monitoring. The species is considered to be of concern however, given that it is slow-reproducing and faces widespread heavy fishing pressure. There is evidence that its numbers have recently declined in the Maldives. Furthermore, most bignose shark bycatch occurs in international waters
International waters
The terms international waters or trans-boundary waters apply where any of the following types of bodies of water transcend international boundaries: oceans, large marine ecosystems, enclosed or semi-enclosed regional seas and estuaries, rivers, lakes, groundwater systems , and wetlands.Oceans,...
, where a single stock
Fish stock
Fish stocks are subpopulations of a particular species of fish, for which intrinsic parameters are the only significant factors in determining population dynamics, while extrinsic factors are considered to be insignificant.-The stock concept:All species have geographic limits to their...
may be affected by multiple fisheries. It is listed as a "highly migratory species" under the 1995 UN Agreement on the Conservation and Management of Straddling Fish Stocks and Highly Migratory Fish Stocks (UNFSA), but thus far this has not led to significant conservation measures. Regionally, the IUCN has assessed the bignose shark as Near Threatened
Near Threatened
Near Threatened is a conservation status assigned to species or lower taxa that may be considered threatened with extinction in the near future, although it does not currently qualify for the threatened status...
in the northwestern Atlantic. Though specific data is lacking, it is suspected to have declined there because it is commonly misidentified as the sandbar shark, and thus the known decline in sandbar shark numbers resulting from US longline fishing may represent a decline in bignose shark numbers as well. This species has been assessed as Least Concern
Least Concern
Least Concern is an IUCN category assigned to extant taxon or lower taxa which have been evaluated but do not qualify for any other category. As such they do not qualify as threatened, Near Threatened, or Conservation Dependent...
in Australian waters, where it faces no significant threats.