Bronze whaler
Encyclopedia
The copper shark, bronze whaler, or narrowtooth shark (Carcharhinus brachyurus) is a species
of requiem shark
, family
Carcharhinidae, and the only member of its genus found mostly at temperate
latitude
s. It is distributed in a number of separate populations in the northeastern and southwestern Atlantic, off southern Africa
, in the northwestern and eastern Pacific, and around Australia
and New Zealand
, with scattered reports from equator
ial regions. This species can be found from brackish river
s and estuaries, to shallow bay
s and harbor
s, to offshore waters 100 m (328.1 ft) deep or more. Females are found apart from males for most of the year, and conduct seasonal migrations
. A large species reaching 3.3 m (10.8 ft) long, the copper shark is difficult to distinguish from other large requiem sharks. It is characterized by its narrow, hook-shaped upper teeth, lack of a prominent ridge between the dorsal fin
s, and plain bronze coloration.
Feeding mainly on cephalopod
s, bony fishes, and other cartilaginous fishes, the copper shark is a fast-swimming predator that often hunts in large groups, utilizing their numbers to their advantage. Off South Africa
, this species associates closely with the annual sardine run
, involving millions of southern African pilchard (Sardinops sagax). Like other requiem sharks, it is viviparous, with the developing embryo
s mainly nourished through a placenta
l connection formed from the depleted yolk sac
. Females bear litters of 7 to 24 pups every other year in coastal nursery areas, after a gestation period
of 12 or perhaps as long as 21 months. It is extremely slow-growing, with males and females not reaching maturity until 13–19 and 19–20 years of age respectively.
While not noted as being especially dangerous to humans, the copper shark has been responsible for a number of non-fatal attacks
, particularly on spear fishers
and bathers. This species is valued by commercial
and recreational fisheries
throughout its range, and utilized as food. It is very susceptible to population depletion due to its low growth and reproductive rates, and its numbers are believed to have declined in some areas. As a result, the International Union for Conservation of Nature (IUCN) has assessed it as Near Threatened
.
's 1865 Carcharias remotus, until it was found that the type specimen associated with that name is actually a blacknose shark
(C. acronotus). Thus, this shark was often referred to as C. remotus in older literature. An even earlier name, Richard Owen
's 1853 Galeolamna greyi, is of questionable taxonomic status as it was based solely on a set of now-destroyed jaws that may or may not have belonged to a copper shark. Modern authors have assigned this species to the genus Carcharhinus.
The specific epithet brachyurus is derived from the Greek
brachys ("short") and oura ("tail"). The name "whaler" originated in the 19th century, applied by the crews of whaling vessels in the Pacific who saw large sharks of various species congregating around harpooned whale carcasses. This species may also be referred to as black-tipped whaler, cocktail shark or cocktail whaler, or New Zealand whaler, as well as by the shortened "bronze", "bronzie", or "cocktail". Günther originally referred to four syntype
s: a stuffed specimen from Antarctica and another from New Zealand
, which have since been lost, and two fetus
es from Australia
that were later discovered to be bull shark
s (C. leucas). In the interests of taxonomic stability, in 1982 Jack Garrick designated a 2.4 m (7.9 ft) long female caught off Whanganui
, New Zealand as a new type specimen.
and returned inconclusive results: in 1982 Jack Garrick placed it by itself as a grouping within Carcharhinus, while in 1988 Leonard Compagno
placed it in an informal "transitional group" that also contained the blacknose shark (C. acronotus), the blacktip reef shark
(C. melanopterus), the nervous shark
(C. cautus), the silky shark
(C. falciformis), and the night shark
(C. signatus). Gavin Naylor's 1992 allozyme
study concluded that the closest relative of the copper shark is the spinner shark
(C. brevipinna), but could not resolve their wider relationships with the rest of the genus. Fossil
ized teeth from the copper shark have been recovered from the Pungo River
in North Carolina
, dating to the Miocene
(23–5.3 Ma), from Tuscany
, dating to the Pliocene
(5.3–2.6 Ma), and from Costa Mesa
in California
, dating to the Late Pleistocene
(126,000–12,000 years ago).
rather than tropical waters, in temperatures above 12 °C (53.6 °F). It is widely distributed but as disjunct
regional populations with little to no interchange between them. In the Atlantic, this shark occurs from the Mediterranean Sea
to Morocco
and the Canary Islands
, off Argentina
, and off Namibia
and South Africa
(where there may be two separate populations), with infrequent records from Mauritania
, the Gulf of Guinea
, and possibly the Gulf of Mexico
. In the Indo-Pacific
, it is found from the East China Sea
to Japan
(excluding Hokkaido
) and southern Russia
, off southern Australia
(mostly between Sydney
and Perth
but occasionally further north), and around New Zealand
but not as far as the Kermadec Islands
; there are also unconfirmed reports from the Seychelles
and the Gulf of Thailand
. In the eastern Pacific, it occurs from northern Chile
to Peru
, and from Mexico
to Point Conception
, California
, including the Gulf of California
. The copper shark is common off parts of Argentina, South Africa, Australia, and New Zealand, and rare elsewhere; in many areas its range is ill-defined because of confusion with other species.
Copper sharks can be found from the surf zone
to slightly beyond the continental shelf
in the open ocean, diving to depths of 100 m (328.1 ft) or more. This species commonly enters very shallow habitat
s, including bay
s, shoal
s, and harbor
s, and also inhabits rocky areas and offshore islands. It is tolerant of low and changing salinities
, and has been reported from estuaries and the lower reaches of large river
s. Juveniles inhabit inshore waters less than 30 m (98.4 ft) deep throughout the year, while adults tend to be found further offshore and regularly approach the coast only in spring and summer, when large aggregations can be readily observed in shallow water.
Populations of copper sharks in both hemispheres perform seasonal migrations, in response to temperature changes, reproductive events, and/or prey availability; the movement patterns differ with sex and age. Adult females and juveniles spend winter in the subtropics and generally shift to higher latitudes as spring nears, with pregnant females also moving towards the coast to give birth in inshore nursery areas. Adult males remain in the subtropics for most of the year, except in late winter or spring when they also move into higher latitudes, in time to encounter and mate with post-partum females dispersing from the nurseries. During migrations, individual sharks have been recorded traveling up to 1320 km (820.2 mi). It is philopatric, returning to the same areas year after year.
The copper shark has a slender, streamlined body with a slightly arched profile just behind the head. The snout is rather long and pointed, with the nostrils preceded by low flaps of skin. The round, moderately large eyes are equipped with nictating membranes (protective third eyelids). The mouth has short, subtle furrows at the corners and contains 29–35 upper tooth rows and 29–33 lower tooth rows. The teeth are serrated with single narrow cusps; the upper teeth have a distinctive hooked shape and become more angled towards the corners of the jaw, while the lower teeth are upright. The upper teeth of adult males are longer, narrower, more curved, and more finely serrated than those of adult females and juveniles. The five pairs of gill slit
s are fairly long.
The pectoral fins are large, pointed, and falcate (sickle-shaped). The first dorsal fin
is tall, with a pointed apex and a concave trailing margin; its origin lies about even with the tips of the pectoral fins. The second dorsal fin is small and low, and positioned about opposite to the anal fin. There is usually no ridge between the dorsal fins. The caudal fin has a well-developed lower lobe and a deep ventral notch near the tip of the upper lobe. This species is bronze to olive-gray above with a metallic sheen and sometimes a pink cast, darkening towards the fin tips and margins but not conspicuously so; the color fades quickly to a dull gray-brown after death. The underside is white, which extends onto the flanks as a prominent band. The copper shark is easily mistaken for other large Carcharhinus species, particularly the dusky shark
(C. obscurus), but can be identified by its upper tooth shape, absent or weak interdorsal ridge, and lack of obvious fin markings. It reportedly reaches a maximum length of 3.3 m (10.8 ft) and weight of 305 kilograms (672.4 lb).
s containing up to hundreds of individuals. Some aggregations seem to form for reproductive purposes, while others form in response to concentrations of food. This species may fall prey to larger sharks. Known parasites of the copper shark include the tapeworms Cathetocephalus australis, Dasyrhynchus pacificus and D. talismani, Floriceps minacanthus, Phoreiobothrium robertsoni, and Pseudogrillotia spratti, the leech
Stibarobdella macrothela, and the fluke
Otodistomum veliporum.
The copper shark feeds more towards the bottom of the water column than the top, consuming cephalopod
s, including squid
(Loligo
spp.), cuttlefish
es, and octopus
; bony fishes, including gurnards
, flatfish
es, hakes, catfish
es, jacks
, Australian salmon
, mullets, sea breams, smelts, tuna
s, sardine
s, and anchovies; and cartilaginous fishes, including dogfish sharks (Squalus spp.), stingray
s, skates, electric ray
s, and sawfish
es. Cephalopods and cartilaginous fishes become relatively more important food for sharks over 2 m (6.6 ft) long. Young sharks also consume scyphozoan jellyfish
and crustacean
s, including mud shrimp
s (Callianassa
) and penaeid prawn
s. It does not attack marine mammals, though has been known rarely to scavenge on dolphin
s that had succumbed to fishing nets. The predominant prey of this species off South Africa is the southern African pilchard (Sardinops sagax), which comprise 69–95% of its diet. Every winter, schools of copper sharks follow the "run" of the pilchard
from the Eastern Cape to KwaZulu-Natal
. The gathering of millions of forage fish
attract a multitude of predators, including several species of sharks, of which copper sharks are the most numerous.
Large numbers of copper sharks have been observed hunting together in a seemingly cooperative fashion. Small schooling fish are "herded" into a tight ball, whereupon each shark swims through in turn with its mouth open to feed. For groups of tuna and larger prey, the pursuing sharks may adopt a "wing" formation to force their quarry closer together, with each shark targeting a particular fish and attacking in turn. In False Bay
, South Africa, this species reportedly follows seine net fishing vessels.
of the developing embryo
, once depleted, is converted into a placenta
l connection through which the mother delivers nourishment. Adult females have one functional ovary
, on the right, and two functional uterus
es. The male bites the female as a prelude to mating. In the Southern Hemisphere, mating takes place from October to December (spring and early summer), when both sexes have migrated into offshore waters at higher latitudes. Birthing seems to occur from June to January, peaking in October and November.
Female copper sharks make use of shallow inshore habitats, varying from stretches of open coast to more sheltered bays and inlets, as nurseries. These nurseries provide abundant food and reduce the likelihood of predation by larger members of the species. Known and suspected nursery areas occur off northern North Island
from Waimea Inlet to Hawke Bay
for New Zealand sharks, off Albany
, in and around Gulf St Vincent, and in Port Phillip Bay for Australian sharks, off Niigata
(Japan) for northwestern Pacific sharks, off the Eastern Cape
for South Africa sharks, off Rhodes
(Greece), Nice
(France), and Al Hoceima
(Morocco) for Mediterranean sharks, off Río de Oro
(Western Sahara) for northwest African sharks, off Rio de Janeiro
(Brazil) and Buenos Aires
and Bahía Blanca
(Argentina) for southwestern Atlantic sharks, and off Paita
and Guanape Cove (Peru), in Sebastián Vizcaíno Bay
(Mexico), and in and around San Diego Bay
for eastern Pacific sharks.
Most sources estimate a gestation period
of 12 months, though some data support the interpretation of a 15–21 month long gestation period instead. Females produce litters every other year, with the number of pups ranging from 7 to 24 and averaging 15 or 16. Females off California and the Baja Peninsula tend to bear fewer young relative to other parts of the world. The newborns measure 55–67 cm (21.7–26.4 in) long. The copper shark is among the slowest-growing Carcharhinus species: off South Africa, males reach sexual maturity
at 2–2.4 m (6.6–7.9 ft) long and an age of 13–19 years, while females mature at 2.3–2.5 m (7.5–8.2 ft) long and an age of 19–20 years. Females off Australia mature at a comparable length of 2.5 m (8.2 ft), while females off Argentina mature at a slightly smaller length of 2.2 m (7.2 ft). The maximum lifespan is at least 30 years for males and 25 years for females.
in an attempt to steal catches, and has also bitten several bathers in Australia, where it is abundant. As of May 2009, the International Shark Attack File
listed 33 attacks on people and boats by the copper shark, 17 of them unprovoked and none fatal. However, witnesses attributed a fatal attack on September 2011 in Bunker Bay, Western Australia to a copper shark. Like many large, active sharks, this species adapts poorly to captivity; it tends to bump into the sides of its enclosure, and the resulting abrasions then become infected with often fatal consequences.
Commercial fisheries
for the copper shark exist off New Zealand, Australia (though the "bronze whaler fishery" of Western Australia
actually takes mostly dusky sharks), South Africa, Brazil, Uruguay, Argentina, Mexico, and China; it also contributes to the bycatch
of other commercial fisheries across its range. This species is caught in gillnet
s and on bottom longlines, and to a much lesser extent in bottom trawls and on pelagic longlines. The meat is sold for human consumption. The copper shark is also popular with recreational fishers
in New Zealand, Australia, South Africa, Argentina, Mexico and California, predominantly by anglers but also by bowfishers
and gillnetters. In New Zealand, it is the Carcharhinus species most frequently caught by sport fishers and sustains a small, summer recreational fishery in northern North Island, that mainly captures pregnant and post-partum females and for the most part practices tag and release
. A tag and release program is also practiced in Namibia.
worldwide, noting that its long maturation time and low reproductive rate render it highly susceptible to fishing depletion. Regionally, the IUCN has listed this species under Least Concern
off Australia, New Zealand, and South Africa, where fisheries are generally well-managed; the local copper shark population for each of those three countries is contained almost entirely within their respective Exclusive Economic Zone
s (EEZ). Reported catches by New Zealand have steadily declined from a peak of 40 tons in 1995/96 to 20 tons 2001/02, though it is uncertain whether this reflects a genuine decline or changing fishing habits and the species remains relatively common.
In the eastern Pacific, the copper shark is rare and little fishery information is available, leading to an assessment of Data Deficient
. However, catch declines across all shark and ray
species have been documented in the heavily-fished Gulf of California. Off East Asia
, the copper shark has been assessed as Vulnerable
; though species-specific data is unavailable, shark populations overall have been decimated in the region. The number of large adults have been too low to sustain targeted fisheries since the 1970s, and most of the current shark catch consists of small juveniles. Additional threats to this species include the degradation and destruction
of its coastal nurseries from development, pollution
, and aquaculture
, mortality from shark net
s used to protect beaches in South Africa and Australia, and persecution by fish farmers in southern Australia.
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, and the only member of its genus found mostly at temperate
Temperate
In geography, temperate or tepid latitudes of the globe lie between the tropics and the polar circles. The changes in these regions between summer and winter are generally relatively moderate, rather than extreme hot or cold...
latitude
Latitude
In geography, the latitude of a location on the Earth is the angular distance of that location south or north of the Equator. The latitude is an angle, and is usually measured in degrees . The equator has a latitude of 0°, the North pole has a latitude of 90° north , and the South pole has a...
s. It is distributed in a number of separate populations in the northeastern and southwestern Atlantic, off southern Africa
Southern Africa
Southern Africa is the southernmost region of the African continent, variably defined by geography or geopolitics. Within the region are numerous territories, including the Republic of South Africa ; nowadays, the simpler term South Africa is generally reserved for the country in English.-UN...
, in the northwestern and eastern Pacific, and around 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...
and New Zealand
New Zealand
New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...
, with scattered reports from equator
Equator
An equator is the intersection of a sphere's surface with the plane perpendicular to the sphere's axis of rotation and containing the sphere's center of mass....
ial regions. This species can be found from brackish river
River
A river is a natural watercourse, usually freshwater, flowing towards an ocean, a lake, a sea, or another river. In a few cases, a river simply flows into the ground or dries up completely before reaching another body of water. Small rivers may also be called by several other names, including...
s and estuaries, to shallow bay
Bay
A bay is an area of water mostly surrounded by land. Bays generally have calmer waters than the surrounding sea, due to the surrounding land blocking some waves and often reducing winds. Bays also exist as an inlet in a lake or pond. A large bay may be called a gulf, a sea, a sound, or a bight...
s and harbor
Harbor
A harbor or harbour , or haven, is a place where ships, boats, and barges can seek shelter from stormy weather, or else are stored for future use. Harbors can be natural or artificial...
s, to offshore waters 100 m (328.1 ft) deep or more. Females are found apart from males for most of the year, and conduct seasonal migrations
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...
. A large species reaching 3.3 m (10.8 ft) long, the copper shark is difficult to distinguish from other large requiem sharks. It is characterized by its narrow, hook-shaped upper teeth, lack of a prominent ridge between the 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, and plain bronze coloration.
Feeding mainly on 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, bony fishes, and other cartilaginous fishes, the copper shark is a fast-swimming predator that often hunts in large groups, utilizing their numbers to their advantage. Off 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...
, this species associates closely with the annual sardine run
Sardine run
The sardine run of southern Africa occurs from May through July when billions of sardines – or more specifically the Southern African pilchard Sardinops sagax – spawn in the cool waters of the Agulhas Bank and move northward along the east coast of South Africa...
, involving millions of southern African pilchard (Sardinops sagax). Like other requiem sharks, it is viviparous, with 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 mainly nourished through 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 formed from 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...
. Females bear litters of 7 to 24 pups every other year in coastal nursery areas, after 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 12 or perhaps as long as 21 months. It is extremely slow-growing, with males and females not reaching maturity until 13–19 and 19–20 years of age respectively.
While not noted as being especially dangerous to humans, the copper shark has been responsible for a number of non-fatal attacks
Shark attack
A shark attack is an attack on a human by a shark. Every year around 60 shark attacks are reported worldwide, although death is quite unusual. Despite the relative rarity of shark attacks, the fear of sharks is a common phenomenon, having been fueled by the occasional instances of serial attacks,...
, particularly on spear fishers
Spearfishing
Spearfishing is an ancient method of fishing that has been used throughout the world for millennia. Early civilizations were familiar with the custom of spearing fish from rivers and streams using sharpened sticks....
and bathers. This species is valued by commercial
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...
and recreational fisheries
Recreational fishing
Recreational fishing, also called sport fishing, is fishing for pleasure or competition. It can be contrasted with commercial fishing, which is fishing for profit, or subsistence fishing, which is fishing for survival....
throughout its range, and utilized as food. It is very susceptible to population depletion due to its low growth and reproductive rates, and its numbers are believed to have declined in some areas. As a result, the International Union for Conservation of Nature (IUCN) has assessed it 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...
.
Taxonomy
Because of its very patchy range, the copper shark has been scientifically described several times from different locales. The earliest valid description is presently considered to be British zoologist Albert Günther's account of Carcharias brachyurus in the 1870 eighth volume of Catalogue of the fishes in the British Museum. The earliest name was once thought to be Auguste DumérilAuguste Duméril
Auguste Henri André Duméril was a French zoologist. He was professor of Herpetology and Ichthyology at the Muséum National d'Histoire Naturelle in Paris from 1857. His father André Marie Constant Duméril was also a zoologist...
's 1865 Carcharias remotus, until it was found that the type specimen associated with that name is actually a blacknose shark
Blacknose shark
The blacknose shark is a species of requiem shark, family Carcharhinidae, common in the tropical and subtropical waters of the western Atlantic Ocean. This species generally inhabits coastal seagrass, sand, or rubble habitats, with adults preferring deeper water than juveniles...
(C. acronotus). Thus, this shark was often referred to as C. remotus in older literature. An even earlier name, Richard Owen
Richard Owen
Sir Richard Owen, FRS KCB was an English biologist, comparative anatomist and palaeontologist.Owen is probably best remembered today for coining the word Dinosauria and for his outspoken opposition to Charles Darwin's theory of evolution by natural selection...
's 1853 Galeolamna greyi, is of questionable taxonomic status as it was based solely on a set of now-destroyed jaws that may or may not have belonged to a copper shark. Modern authors have assigned this species to the genus Carcharhinus.
The specific epithet brachyurus is derived from the Greek
Greek language
Greek is an independent branch of the Indo-European family of languages. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. Its writing system has been the Greek alphabet for the majority of its history;...
brachys ("short") and oura ("tail"). The name "whaler" originated in the 19th century, applied by the crews of whaling vessels in the Pacific who saw large sharks of various species congregating around harpooned whale carcasses. This species may also be referred to as black-tipped whaler, cocktail shark or cocktail whaler, or New Zealand whaler, as well as by the shortened "bronze", "bronzie", or "cocktail". Günther originally referred to four syntype
Syntype
In biological nomenclature, a syntype is a term used to indicate a specimen with a special status.In zoological nomenclature, a syntype is defined as "Each specimen of a type series from which neither a holotype nor a lectotype has been designated [Arts. 72.1.2, 73.2, 74]. The syntypes...
s: a stuffed specimen from Antarctica and another from New Zealand
New Zealand
New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...
, which have since been lost, and two fetus
Fetus
A fetus is a developing mammal or other viviparous vertebrate after the embryonic stage and before birth.In humans, the fetal stage of prenatal development starts at the beginning of the 11th week in gestational age, which is the 9th week after fertilization.-Etymology and spelling variations:The...
es from 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...
that were later discovered to be bull shark
Bull shark
The bull shark, Carcharhinus leucas, also known as Zambezi shark or unofficially known as Zambi in Africa and Nicaragua shark in Nicaragua, is a shark common worldwide in warm, shallow waters along coasts and in rivers...
s (C. leucas). In the interests of taxonomic stability, in 1982 Jack Garrick designated a 2.4 m (7.9 ft) long female caught off Whanganui
Whanganui
Various places in New Zealand are called Whanganui:*Whanganui, a city at the mouth of the Whanganui River, also often spelled "Wanganui", Manawatu-Wanganui Region*Whanganui District, Manawatu-Wanganui Region*Whanganui Island, Waikato Region...
, New Zealand as a new type specimen.
Phylogeny and evolution
The first efforts to determine the evolutionary relationships of the copper shark were based on morphologyMorphology (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....
and returned inconclusive results: in 1982 Jack Garrick placed it by itself as a grouping within Carcharhinus, while in 1988 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,...
placed it in an informal "transitional group" that also contained the blacknose shark (C. acronotus), the blacktip reef shark
Blacktip reef shark
The blacktip reef shark is a species of requiem shark, family Carcharhinidae, easily identified by the prominent black tips on its fins...
(C. melanopterus), the nervous shark
Nervous shark
The nervous shark, Carcharhinus cautus, is a requiem shark of the family Carcharhinidae, found in the western Pacific Ocean between latitudes 5° S and 30° S. Its length is up to about 1.5 m....
(C. cautus), the silky shark
Silky shark
The silky shark is a species of requiem shark, family Carcharhinidae, named for the smooth texture of its skin. It is one of the most abundant sharks in the pelagic zone, and can be found around the world in tropical waters. Highly mobile and migratory, this shark is most often found over the edge...
(C. falciformis), and the night shark
Night shark
The night shark is a species of requiem shark, family Carcharhinidae, found in the temperate and tropical waters of the Atlantic Ocean...
(C. signatus). Gavin Naylor's 1992 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....
study concluded that the closest relative of the copper shark is the spinner shark
Spinner shark
The spinner shark is a species of requiem shark, family Carcharhinidae, named for the spinning leaps it makes as a part of its feeding strategy. This species occurs in tropical and warm temperate waters worldwide, except for in the eastern Pacific Ocean...
(C. brevipinna), but could not resolve their wider relationships with the rest of the genus. Fossil
Fossil
Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...
ized teeth from the copper shark have been recovered from the Pungo River
Pungo River
The Pungo River is a river in eastern North Carolina, USA. It originally began in the Great Dismal Swamp in Washington County, North Carolina; the upper part of the river has since been supplanted by the Pungo River Canal, dug in the 1950s to improve drainage of local farmland. The river flows...
in North Carolina
North Carolina
North Carolina is a state located in the southeastern United States. The state borders South Carolina and Georgia to the south, Tennessee to the west and Virginia to the north. North Carolina contains 100 counties. Its capital is Raleigh, and its largest city is Charlotte...
, dating to the Miocene
Miocene
The Miocene is a geological epoch of the Neogene Period and extends from about . The Miocene was named by Sir Charles Lyell. Its name comes from the Greek words and and means "less recent" because it has 18% fewer modern sea invertebrates than the Pliocene. The Miocene follows the Oligocene...
(23–5.3 Ma), from Tuscany
Tuscany
Tuscany is a region in Italy. It has an area of about 23,000 square kilometres and a population of about 3.75 million inhabitants. The regional capital is Florence ....
, dating to the Pliocene
Pliocene
The Pliocene Epoch is the period in the geologic timescale that extends from 5.332 million to 2.588 million years before present. It is the second and youngest epoch of the Neogene Period in the Cenozoic Era. The Pliocene follows the Miocene Epoch and is followed by the Pleistocene Epoch...
(5.3–2.6 Ma), and from Costa Mesa
Costa Mesa, California
Costa Mesa is a city in Orange County, California. The population was 109,960 at the 2010 census. Since its incorporation in 1953, the city has grown from a semi-rural farming community of 16,840 to a primarily suburban and "edge" city with an economy based on retail, commerce, and light...
in California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...
, dating to the Late Pleistocene
Late Pleistocene
The Late Pleistocene is a stage of the Pleistocene Epoch. The beginning of the stage is defined by the base of the Eemian interglacial phase before the final glacial episode of the Pleistocene 126,000 ± 5,000 years ago. The end of the stage is defined exactly at 10,000 Carbon-14 years BP...
(126,000–12,000 years ago).
Distribution and habitat
The copper shark is the only member of its genus largely found in temperateTemperate
In geography, temperate or tepid latitudes of the globe lie between the tropics and the polar circles. The changes in these regions between summer and winter are generally relatively moderate, rather than extreme hot or cold...
rather than tropical waters, in temperatures above 12 °C (53.6 °F). It is widely distributed but as disjunct
Disjunct distribution
In biology, a taxon with a disjunct distribution is one that has two or more groups that are related but widely separated from each other geographically...
regional populations with little to no interchange between them. In the Atlantic, this shark occurs from 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...
to Morocco
Morocco
Morocco , officially the Kingdom of Morocco , is a country located in North Africa. It has a population of more than 32 million and an area of 710,850 km², and also primarily administers the disputed region of the Western Sahara...
and the Canary Islands
Canary Islands
The Canary Islands , also known as the Canaries , is a Spanish archipelago located just off the northwest coast of mainland Africa, 100 km west of the border between Morocco and the Western Sahara. The Canaries are a Spanish autonomous community and an outermost region of the European Union...
, off Argentina
Argentina
Argentina , officially the Argentine Republic , is the second largest country in South America by land area, after Brazil. It is constituted as a federation of 23 provinces and an autonomous city, Buenos Aires...
, and off Namibia
Namibia
Namibia, officially the Republic of Namibia , is a country in southern Africa whose western border is the Atlantic Ocean. It shares land borders with Angola and Zambia to the north, Botswana to the east and South Africa to the south and east. It gained independence from South Africa on 21 March...
and 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...
(where there may be two separate populations), with infrequent records from Mauritania
Mauritania
Mauritania is a country in the Maghreb and West Africa. It is bordered by the Atlantic Ocean in the west, by Western Sahara in the north, by Algeria in the northeast, by Mali in the east and southeast, and by Senegal in the southwest...
, the Gulf of Guinea
Gulf of Guinea
The Gulf of Guinea is the northeasternmost part of the tropical Atlantic Ocean between Cape Lopez in Gabon, north and west to Cape Palmas in Liberia. The intersection of the Equator and Prime Meridian is in the gulf....
, and possibly 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...
. In the Indo-Pacific
Indo-Pacific
The Indo-Pacific is a biogeographic region of the Earth's seas, comprising the tropical waters of the Indian Ocean, the western and central Pacific Ocean, and the seas connecting the two in the general area of Indonesia...
, it is found from the East China Sea
East China Sea
The East China Sea is a marginal sea east of China. It is a part of the Pacific Ocean and covers an area of 1,249,000 km² or 750,000 square miles.-Geography:...
to Japan
Japan
Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...
(excluding Hokkaido
Hokkaido
, formerly known as Ezo, Yezo, Yeso, or Yesso, is Japan's second largest island; it is also the largest and northernmost of Japan's 47 prefectural-level subdivisions. The Tsugaru Strait separates Hokkaido from Honshu, although the two islands are connected by the underwater railway Seikan Tunnel...
) and southern Russia
Russia
Russia or , officially known as both Russia and the Russian Federation , is a country in northern Eurasia. It is a federal semi-presidential republic, comprising 83 federal subjects...
, off southern 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...
(mostly between Sydney
Sydney
Sydney is the most populous city in Australia and the state capital of New South Wales. Sydney is located on Australia's south-east coast of the Tasman Sea. As of June 2010, the greater metropolitan area had an approximate population of 4.6 million people...
and Perth
Perth, Western Australia
Perth is the capital and largest city of the Australian state of Western Australia and the fourth most populous city in Australia. The Perth metropolitan area has an estimated population of almost 1,700,000....
but occasionally further north), and around New Zealand
New Zealand
New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...
but not as far as the Kermadec Islands
Kermadec Islands
The Kermadec Islands are a subtropical island arc in the South Pacific Ocean northeast of New Zealand's North Island, and a similar distance southwest of Tonga...
; there are also unconfirmed reports from the Seychelles
Seychelles
Seychelles , officially the Republic of Seychelles , is an island country spanning an archipelago of 115 islands in the Indian Ocean, some east of mainland Africa, northeast of the island of Madagascar....
and the Gulf of Thailand
Gulf of Thailand
The Gulf of Thailand , also known in to Malays as Teluk Siam literally meant Gulf of Siam, is a shallow arm of the South China Sea.-Geography:...
. In the eastern Pacific, it occurs from northern Chile
Chile
Chile ,officially the Republic of Chile , is a country in South America occupying a long, narrow coastal strip between the Andes mountains to the east and the Pacific Ocean to the west. It borders Peru to the north, Bolivia to the northeast, Argentina to the east, and the Drake Passage in the far...
to Peru
Peru
Peru , officially the Republic of Peru , is a country in western South America. It is bordered on the north by Ecuador and Colombia, on the east by Brazil, on the southeast by Bolivia, on the south by Chile, and on the west by the Pacific Ocean....
, and from Mexico
Mexico
The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...
to Point Conception
Point Conception
Point Conception is a headland along the Pacific coast of U.S. state of California, located in southwestern Santa Barbara County. It is the point where the Santa Barbara Channel meets the Pacific Ocean, and as the corner between the mostly north-south trending portion of coast to the north and the...
, California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...
, including 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...
. The copper shark is common off parts of Argentina, South Africa, Australia, and New Zealand, and rare elsewhere; in many areas its range is ill-defined because of confusion with other species.
Copper sharks can be found from the surf zone
Surf zone
As ocean surface waves come closer to shore they break, forming the foamy, bubbly surface we call surf. The region of breaking waves defines the surf zone. After breaking in the surf zone, the waves continue to move in, and they run up onto the sloping front of the beach, forming an uprush of...
to slightly beyond 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,...
in the open ocean, diving to depths of 100 m (328.1 ft) or more. This species commonly enters very shallow habitat
Habitat
* Habitat , a place where a species lives and grows*Human habitat, a place where humans live, work or play** Space habitat, a space station intended as a permanent settlement...
s, including bay
Bay
A bay is an area of water mostly surrounded by land. Bays generally have calmer waters than the surrounding sea, due to the surrounding land blocking some waves and often reducing winds. Bays also exist as an inlet in a lake or pond. A large bay may be called a gulf, a sea, a sound, or a bight...
s, shoal
Shoal
Shoal, shoals or shoaling may mean:* Shoal, a sandbank or reef creating shallow water, especially where it forms a hazard to shipping* Shoal draught , of a boat with shallow draught which can pass over some shoals: see Draft...
s, and harbor
Harbor
A harbor or harbour , or haven, is a place where ships, boats, and barges can seek shelter from stormy weather, or else are stored for future use. Harbors can be natural or artificial...
s, and also inhabits rocky areas and offshore islands. It is tolerant of low and changing salinities
Salinity
Salinity is the saltiness or dissolved salt content of a body of water. It is a general term used to describe the levels of different salts such as sodium chloride, magnesium and calcium sulfates, and bicarbonates...
, and has been reported from estuaries and the lower reaches of large river
River
A river is a natural watercourse, usually freshwater, flowing towards an ocean, a lake, a sea, or another river. In a few cases, a river simply flows into the ground or dries up completely before reaching another body of water. Small rivers may also be called by several other names, including...
s. Juveniles inhabit inshore waters less than 30 m (98.4 ft) deep throughout the year, while adults tend to be found further offshore and regularly approach the coast only in spring and summer, when large aggregations can be readily observed in shallow water.
Populations of copper sharks in both hemispheres perform seasonal migrations, in response to temperature changes, reproductive events, and/or prey availability; the movement patterns differ with sex and age. Adult females and juveniles spend winter in the subtropics and generally shift to higher latitudes as spring nears, with pregnant females also moving towards the coast to give birth in inshore nursery areas. Adult males remain in the subtropics for most of the year, except in late winter or spring when they also move into higher latitudes, in time to encounter and mate with post-partum females dispersing from the nurseries. During migrations, individual sharks have been recorded traveling up to 1320 km (820.2 mi). It is philopatric, returning to the same areas year after year.
Description
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 fairly long.
The pectoral fins are large, pointed, and falcate (sickle-shaped). 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...
is tall, with a pointed apex and a concave trailing margin; its origin lies about even with the tips of the pectoral fins. The second dorsal fin is small and low, and positioned about opposite to the anal fin. There is usually no ridge between the dorsal fins. The caudal fin has a well-developed lower lobe and a deep ventral notch near the tip of the upper lobe. This species is bronze to olive-gray above with a metallic sheen and sometimes a pink cast, darkening towards the fin tips and margins but not conspicuously so; the color fades quickly to a dull gray-brown after death. The underside is white, which extends onto the flanks as a prominent band. The copper shark is easily mistaken for other large Carcharhinus species, particularly 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), but can be identified by its upper tooth shape, absent or weak interdorsal ridge, and lack of obvious fin markings. It reportedly reaches a maximum length of 3.3 m (10.8 ft) and weight of 305 kilograms (672.4 lb).
Biology and ecology
Fast and active, the copper shark may be encountered alone, in pairs, or in loosely organized schoolShoaling and schooling
In biology, any group of fish that stay together for social reasons are said to be shoaling , and if, in addition, the group is swimming in the same direction in a coordinated manner, they are said to be schooling . In common usage, the terms are sometimes used rather loosely...
s containing up to hundreds of individuals. Some aggregations seem to form for reproductive purposes, while others form in response to concentrations of food. This species may fall prey to larger sharks. Known parasites of the copper shark include the tapeworms Cathetocephalus australis, Dasyrhynchus pacificus and D. talismani, Floriceps minacanthus, Phoreiobothrium robertsoni, and Pseudogrillotia spratti, the leech
Leech
Leeches are segmented worms that belong to the phylum Annelida and comprise the subclass Hirudinea. Like other oligochaetes such as earthworms, leeches share a clitellum and are hermaphrodites. Nevertheless, they differ from other oligochaetes in significant ways...
Stibarobdella macrothela, and the fluke
Trematoda
Trematoda is a class within the phylum Platyhelminthes that contains two groups of parasitic flatworms, commonly referred to as "flukes".-Taxonomy and biodiversity:...
Otodistomum veliporum.
Feeding
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, including squid
Squid
Squid are cephalopods of the order Teuthida, which comprises around 300 species. Like all other cephalopods, squid have a distinct head, bilateral symmetry, a mantle, and arms. Squid, like cuttlefish, have eight arms arranged in pairs and two, usually longer, tentacles...
(Loligo
Loligo
Loligo is a genus of squids and one of the most representative and widely distributed groups of myopsid squids.The genus was first described by Jean Baptiste Lamarck in 1798. However, the name had been used earlier than Lamarck and might even have been used by Pliny...
spp.), cuttlefish
Cuttlefish
Cuttlefish are marine animals of the order Sepiida. They belong to the class Cephalopoda . Despite their name, cuttlefish are not fish but molluscs....
es, and octopus
Octopus
The octopus is a cephalopod mollusc of the order Octopoda. Octopuses have two eyes and four pairs of arms, and like other cephalopods they are bilaterally symmetric. An octopus has a hard beak, with its mouth at the center point of the arms...
; bony fishes, including gurnards
Sea robin
Sea robins, also known as gurnard, are bottom-feeding scorpaeniform fishes in the family Triglidae. They get their name from their large pectoral fins, which, when swimming, open and close like a bird's wings in flight....
, 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, hakes, catfish
Catfish
Catfishes are a diverse group of ray-finned fish. Named for their prominent barbels, which resemble a cat's whiskers, catfish range in size and behavior from the heaviest and longest, the Mekong giant catfish from Southeast Asia and the second longest, the wels catfish of Eurasia, to detritivores...
es, jacks
Carangidae
Carangidae is a family of fish which includes the jacks, pompanos, jack mackerels, and scads.They are marine fish found in the Atlantic, Indian and Pacific Oceans...
, Australian salmon
Australian salmon
Australian Salmon, , are medium-sized perciform marine fish of the small family Arripidae . Four species are recognized, all within the genus Arripis...
, mullets, sea breams, smelts, 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...
s, sardine
Sardine
Sardines, or pilchards, are several types of small, oily fish related to herrings, family Clupeidae. Sardines are named after the Mediterranean island of Sardinia, around which they were once abundant....
s, and anchovies; and cartilaginous fishes, including dogfish sharks (Squalus spp.), 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, skates, electric ray
Electric ray
The electric rays are a group of rays, flattened cartilaginous fish with enlarged pectoral fins, comprising the order Torpediniformes. They are known for being capable of producing an electric discharge, ranging from as little as 8 volts up to 220 volts depending on species, used to stun prey and...
s, and sawfish
Sawfish
Sawfish, also known as the Carpenter Shark, are a family of rays, characterized by a long, toothy nose extension snout. Several species can grow to approximately . The family as a whole is largely unknown and little studied...
es. Cephalopods and cartilaginous fishes become relatively more important food for sharks over 2 m (6.6 ft) long. Young sharks also consume scyphozoan jellyfish
Scyphozoa
Scyphozoa is a class within the phylum Cnidaria, sometimes referred to as the "true jellyfish".The class name Scyphozoa comes from the Greek word skyphos , denoting a kind of drinking cup and alluding to the cup shape of the organism....
and crustacean
Crustacean
Crustaceans form a very large group of arthropods, usually treated as a subphylum, which includes such familiar animals as crabs, lobsters, crayfish, shrimp, krill and barnacles. The 50,000 described species range in size from Stygotantulus stocki at , to the Japanese spider crab with a leg span...
s, including mud shrimp
Thalassinidea
Thalassinidea is an infraorder of decapod crustaceans that live in burrows in muddy bottoms of the world's oceans. In Australian English, the littoral thalassinidean Trypaea australiensis is referred to as the yabby , frequently used as bait for estuarine fishing; elsewhere, however, they are...
s (Callianassa
Callianassa (genus)
Callianassa is a genus of mud shrimps, in the family Callianassidae. Three of the species in this genus Callianassa is a genus of mud shrimps, in the family Callianassidae. Three of the species in this genus Callianassa is a genus of mud shrimps, in the family Callianassidae. Three of the species...
) and penaeid prawn
Prawn
Prawns are decapod crustaceans of the sub-order Dendrobranchiata. There are 540 extant species, in seven families, and a fossil record extending back to the Devonian...
s. It does not attack marine mammals, though has been known rarely to scavenge on dolphin
Dolphin
Dolphins are marine mammals that are closely related to whales and porpoises. There are almost forty species of dolphin in 17 genera. They vary in size from and , up to and . They are found worldwide, mostly in the shallower seas of the continental shelves, and are carnivores, mostly eating...
s that had succumbed to fishing nets. The predominant prey of this species off South Africa is the southern African pilchard (Sardinops sagax), which comprise 69–95% of its diet. Every winter, schools of copper sharks follow the "run" of the pilchard
Sardine run
The sardine run of southern Africa occurs from May through July when billions of sardines – or more specifically the Southern African pilchard Sardinops sagax – spawn in the cool waters of the Agulhas Bank and move northward along the east coast of South Africa...
from the Eastern Cape to KwaZulu-Natal
KwaZulu-Natal
KwaZulu-Natal is a province of South Africa. Prior to 1994, the territory now known as KwaZulu-Natal was made up of the province of Natal and the homeland of KwaZulu....
. The gathering of millions of forage fish
Forage fish
Forage fish, also called prey fish or bait fish, are small fish which are preyed on by larger predators for food. Predators include other larger fish, seabirds and marine mammals. Typical ocean forage fish feed near the base of the food chain on plankton, often by filter feeding...
attract a multitude of predators, including several species of sharks, of which copper sharks are the most numerous.
Large numbers of copper sharks have been observed hunting together in a seemingly cooperative fashion. Small schooling fish are "herded" into a tight ball, whereupon each shark swims through in turn with its mouth open to feed. For groups of tuna and larger prey, the pursuing sharks may adopt a "wing" formation to force their quarry closer together, with each shark targeting a particular fish and attacking in turn. In False Bay
False Bay
False Bay is a body of water defined by Cape Hangklip and the Cape Peninsula in the extreme South-West of South Africa.- Description and location :...
, South Africa, this species reportedly follows seine net fishing vessels.
Life history
Like other members of its family, the copper shark is viviparous, in which the yolk sacYolk 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...
of 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...
, once depleted, 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. Adult females have one functional ovary
Ovary
The ovary is an ovum-producing reproductive organ, often found in pairs as part of the vertebrate female reproductive system. Ovaries in anatomically female individuals are analogous to testes in anatomically male individuals, in that they are both gonads and endocrine glands.-Human anatomy:Ovaries...
, on the right, and two functional uterus
Uterus
The uterus or womb is a major female hormone-responsive reproductive sex organ of most mammals including humans. One end, the cervix, opens into the vagina, while the other is connected to one or both fallopian tubes, depending on the species...
es. The male bites the female as a prelude to mating. In the Southern Hemisphere, mating takes place from October to December (spring and early summer), when both sexes have migrated into offshore waters at higher latitudes. Birthing seems to occur from June to January, peaking in October and November.
Female copper sharks make use of shallow inshore habitats, varying from stretches of open coast to more sheltered bays and inlets, as nurseries. These nurseries provide abundant food and reduce the likelihood of predation by larger members of the species. Known and suspected nursery areas occur off northern North Island
North Island
The North Island is one of the two main islands of New Zealand, separated from the much less populous South Island by Cook Strait. The island is in area, making it the world's 14th-largest island...
from Waimea Inlet to Hawke Bay
Hawke Bay
Hawke Bay is a large bay on the eastern coast of the North Island of New Zealand. It stretches from the Mahia Peninsula in the northeast to Cape Kidnappers in the southwest, a distance of some 100 kilometres....
for New Zealand sharks, off Albany
Albany, Western Australia
Albany is a port city in the Great Southern region of Western Australia, some 418 km SE of Perth, the state capital. As of 2009, Albany's population was estimated at 33,600, making it the 6th-largest city in the state....
, in and around Gulf St Vincent, and in Port Phillip Bay for Australian sharks, off Niigata
Niigata Prefecture
is a prefecture of Japan located on the island of Honshū on the coast of the Sea of Japan. The capital is the city of Niigata. The name "Niigata" literally means "new lagoon".- History :...
(Japan) for northwestern Pacific sharks, off the Eastern Cape
Eastern Cape
The Eastern Cape is a province of South Africa. Its capital is Bhisho, but its two largest cities are Port Elizabeth and East London. It was formed in 1994 out of the "independent" Xhosa homelands of Transkei and Ciskei, together with the eastern portion of the Cape Province...
for South Africa sharks, off Rhodes
Rhodes
Rhodes is an island in Greece, located in the eastern Aegean Sea. It is the largest of the Dodecanese islands in terms of both land area and population, with a population of 117,007, and also the island group's historical capital. Administratively the island forms a separate municipality within...
(Greece), Nice
Nice
Nice is the fifth most populous city in France, after Paris, Marseille, Lyon and Toulouse, with a population of 348,721 within its administrative limits on a land area of . The urban area of Nice extends beyond the administrative city limits with a population of more than 955,000 on an area of...
(France), and Al Hoceima
Al Hoceima
Al Hoceima is a city and port in the north of Morocco and in the center of the Rif Mountains. The Al Hoceima city region has a population of 395.644 and is the capital of the Taza-Al Hoceima-Taounate region...
(Morocco) for Mediterranean sharks, off Río de Oro
Río de Oro
Río de Oro , is, with Saguia el-Hamra, one of the two territories that formed the Spanish province of Spanish Sahara after 1969; it was originally taken as a Spanish colonial possession in the late 19th century...
(Western Sahara) for northwest African sharks, off Rio de Janeiro
Rio de Janeiro
Rio de Janeiro , commonly referred to simply as Rio, is the capital city of the State of Rio de Janeiro, the second largest city of Brazil, and the third largest metropolitan area and agglomeration in South America, boasting approximately 6.3 million people within the city proper, making it the 6th...
(Brazil) and Buenos Aires
Buenos Aires
Buenos Aires is the capital and largest city of Argentina, and the second-largest metropolitan area in South America, after São Paulo. It is located on the western shore of the estuary of the Río de la Plata, on the southeastern coast of the South American continent...
and Bahía Blanca
Bahía Blanca
Bahía Blanca is a city located in the south-west of the province of Buenos Aires, Argentina, by the Atlantic Ocean, and seat of government of Bahía Blanca Partido. It has a population of 274,509 inhabitants according to the...
(Argentina) for southwestern Atlantic sharks, and off Paita
Paita
Paita is a city in northwestern Peru. It is the capital of the Paita Province which is in the Piura Region. It is a leading seaport in that region...
and Guanape Cove (Peru), in Sebastián Vizcaíno Bay
Sebastián Vizcaíno Bay
Sebastián Vizcaíno Bay is a bay along the west coast of the Baja California Peninsula in Mexico. It is part of the El Vizcaíno Biosphere Reserve. It lies off the Pacific coast of Ensenada Municipality and Mulegé Municipality....
(Mexico), and in and around San Diego Bay
San Diego Bay
San Diego Bay is a natural harbor and deepwater port adjacent to San Diego, California. It is 12 mi/19 km long, 1 mi/1.6 km–3 mi/4.8 km wide...
for eastern Pacific sharks.
Most sources estimate 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 12 months, though some data support the interpretation of a 15–21 month long gestation period instead. Females produce litters every other year, with the number of pups ranging from 7 to 24 and averaging 15 or 16. Females off California and the Baja Peninsula tend to bear fewer young relative to other parts of the world. The newborns measure 55–67 cm (21.7–26.4 in) long. The copper shark is among the slowest-growing Carcharhinus species: off South Africa, males reach sexual maturity
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 2–2.4 m (6.6–7.9 ft) long and an age of 13–19 years, while females mature at 2.3–2.5 m (7.5–8.2 ft) long and an age of 19–20 years. Females off Australia mature at a comparable length of 2.5 m (8.2 ft), while females off Argentina mature at a slightly smaller length of 2.2 m (7.2 ft). The maximum lifespan is at least 30 years for males and 25 years for females.
Human interactions
Though large and powerful, the copper shark is not particularly aggressive towards humans unless in the presence of food, and is thus not regarded as especially dangerous. However, it has been known to harass spear fishersSpearfishing
Spearfishing is an ancient method of fishing that has been used throughout the world for millennia. Early civilizations were familiar with the custom of spearing fish from rivers and streams using sharpened sticks....
in an attempt to steal catches, and has also bitten several bathers in Australia, where it is abundant. As of May 2009, the International Shark Attack File
International Shark Attack File
The International Shark Attack File is a global database of shark attacks. It began as an attempt to catalogue shark attacks on servicemen during World War II. The Office of Naval Research funded it from 1958 until 1968. During that time a panel of shark experts developed a standard system for...
listed 33 attacks on people and boats by the copper shark, 17 of them unprovoked and none fatal. However, witnesses attributed a fatal attack on September 2011 in Bunker Bay, Western Australia to a copper shark. Like many large, active sharks, this species adapts poorly to captivity; it tends to bump into the sides of its enclosure, and the resulting abrasions then become infected with often fatal consequences.
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...
for the copper shark exist off New Zealand, Australia (though the "bronze whaler fishery" of Western Australia
Western Australia
Western Australia is a state of Australia, occupying the entire western third of the Australian continent. It is bounded by the Indian Ocean to the north and west, the Great Australian Bight and Indian Ocean to the south, the Northern Territory to the north-east and South Australia to the south-east...
actually takes mostly dusky sharks), South Africa, Brazil, Uruguay, Argentina, Mexico, and China; it also contributes to the bycatch
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...
of other commercial fisheries across its range. This species is caught in 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...
s and on bottom longlines, and to a much lesser extent in bottom trawls and on pelagic longlines. The meat is sold for human consumption. The copper shark is also popular with recreational fishers
Recreational fishing
Recreational fishing, also called sport fishing, is fishing for pleasure or competition. It can be contrasted with commercial fishing, which is fishing for profit, or subsistence fishing, which is fishing for survival....
in New Zealand, Australia, South Africa, Argentina, Mexico and California, predominantly by anglers but also by bowfishers
Bowfishing
Bowfishing is a method of fishing that uses specialized archery equipment to shoot and retrieve fish. Fish are shot with a barbed arrow that is attached with special line to a reel mounted on the bow. Some freshwater species commonly hunted include common carp, grass carp, bighead carp, alligator...
and gillnetters. In New Zealand, it is the Carcharhinus species most frequently caught by sport fishers and sustains a small, summer recreational fishery in northern North Island, that mainly captures pregnant and post-partum females and for the most part practices tag and release
Tag and release
Tag and release is a form of catch and release fishing in which the angler attaches a tag to the fish, records data such as date, time, place, and type of fish on a standardized post card, and submits this card to a fisheries agency or conservation organization...
. A tag and release program is also practiced in Namibia.
Conservation
The International Union for Conservation of Nature (IUCN) has assessed the copper shark as Near ThreatenedNear 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...
worldwide, noting that its long maturation time and low reproductive rate render it highly susceptible to fishing depletion. Regionally, the IUCN has listed this species under 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...
off Australia, New Zealand, and South Africa, where fisheries are generally well-managed; the local copper shark population for each of those three countries is contained almost entirely within their respective Exclusive Economic Zone
Exclusive Economic Zone
Under the law of the sea, an exclusive economic zone is a seazone over which a state has special rights over the exploration and use of marine resources, including production of energy from water and wind. It stretches from the seaward edge of the state's territorial sea out to 200 nautical...
s (EEZ). Reported catches by New Zealand have steadily declined from a peak of 40 tons in 1995/96 to 20 tons 2001/02, though it is uncertain whether this reflects a genuine decline or changing fishing habits and the species remains relatively common.
In the eastern Pacific, the copper shark is rare and little fishery information is available, leading to an assessment of 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...
. However, catch declines across all shark and ray
Elasmobranchii
Elasmobranchii is a subclass of Chondrichthyes or cartilaginous fish, that includes the sharks and the rays and skates .-Evolution:...
species have been documented in the heavily-fished Gulf of California. Off East Asia
East Asia
East Asia or Eastern Asia is a subregion of Asia that can be defined in either geographical or cultural terms...
, the copper shark has been assessed as Vulnerable
Vulnerable species
On 30 January 2010, the IUCN Red List of Threatened Species identified 9694 Vulnerable species, subspecies and varieties, stocks and sub-populations.-References:...
; though species-specific data is unavailable, shark populations overall have been decimated in the region. The number of large adults have been too low to sustain targeted fisheries since the 1970s, and most of the current shark catch consists of small juveniles. Additional threats to this species include the degradation and destruction
Habitat destruction
Habitat destruction is the process in which natural habitat is rendered functionally unable to support the species present. In this process, the organisms that previously used the site are displaced or destroyed, reducing biodiversity. Habitat destruction by human activity mainly for the purpose of...
of its coastal nurseries from development, pollution
Water pollution
Water pollution is the contamination of water bodies . Water pollution occurs when pollutants are discharged directly or indirectly into water bodies without adequate treatment to remove harmful compounds....
, and aquaculture
Aquaculture
Aquaculture, also known as aquafarming, is the farming of aquatic organisms such as fish, crustaceans, molluscs and aquatic plants. Aquaculture involves cultivating freshwater and saltwater populations under controlled conditions, and can be contrasted with commercial fishing, which is the...
, mortality from shark net
Shark net
A shark net is a submerged net placed around beaches to reduce shark attacks on swimmers.Shark nets do not offer complete protection but work on the principle of "fewer sharks, fewer attacks". They reduce occurrence via shark mortality. Reducing the local shark populations is believed to reduce the...
s used to protect beaches in South Africa and Australia, and persecution by fish farmers in southern Australia.