The school shark (''Galeorhinus galeus'') is a

houndshark Houndsharks, the Triakidae, are a family of ground sharks, consisting of about 40 species in nine genera. In some classifications, the family is split into two subfamilies, with ''Mustelus'', '' Scylliogaleus'', and '' Triakis'' in the subfamily ...

of the

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

Triakidae, and the only member of the genus ''Galeorhinus''. Common names also include tope, tope shark, snapper shark, and soupfin shark. It is found worldwide in temperate seas at depths down to about . It can grow to nearly long. It feeds both in midwater and near the seabed, and its reproduction is

ovoviviparous Ovoviviparity, ovovivipary, ovivipary, or aplacental viviparity is a term used as a "bridging" form of reproduction between egg-laying oviparous and live-bearing viviparous reproduction. Ovoviviparous animals possess embryos that develop insi ...

. This shark is caught in

fisheries Fishery can mean either the enterprise of raising or harvesting fish and other aquatic life; or more commonly, the site where such enterprise takes place ( a.k.a. fishing ground). Commercial fisheries include wild fisheries and fish farms, both ...

for its flesh, its fins, and its liver, which has a very high

vitamin A Vitamin A is a fat-soluble vitamin and an essential nutrient for humans. It is a group of organic compounds that includes retinol, retinal (also known as retinaldehyde), retinoic acid, and several provitamin A carotenoids (most notably bet ...

content. The

IUCN The International Union for Conservation of Nature (IUCN; officially International Union for Conservation of Nature and Natural Resources) is an international organization working in the field of nature conservation and sustainable use of natu ...

has classified this species as critically endangered in its

Red List of Threatened Species The International Union for Conservation of Nature (IUCN) Red List of Threatened Species, also known as the IUCN Red List or Red Data Book, founded in 1964, is the world's most comprehensive inventory of the global conservation status of biologi ...

Description

The school shark is a small, shallow-bodied shark with an elongated snout. The large mouth is crescent-shaped and the teeth are of a similar size and shape in both jaws. They are triangular-shaped, small, and flat, set at an oblique angle facing backwards, serrated and with a notch. The spiracles are small. The first dorsal fin is triangular with a straight leading edge and is set just behind the pectoral fins. The second dorsal fin is about the same size as the anal fin and is set immediately above it. The terminal lobe of the caudal fin has a notch in it and is as long as the rest of the fin. School sharks are dark bluish grey on their upper (dorsal) surfaces and white on their bellies (ventral surface). Juveniles have black markings on their fins. Mature sharks range from for males and for females. Galeorhinus galeus head.jpg, Head Galeorhinus galeus jaws.jpg, Jaws Galeorhinus galeus upper teeth.jpg, Upper teeth Galeorhinus galeus lower teeth.jpg, Lower teeth

Distribution

The school shark has a widespread distribution and is found mainly near the seabed around coasts in temperate waters, down to depths around . It occurs in the Northeast Atlantic and Mediterranean Sea, where it is uncommon and the Southwest Atlantic where it occurs between Patagonia and southern Brazil. It also occurs around the coast of Namibia and South Africa. It is present in the Northeast Pacific where it occurs between British Columbia and Baja California, and in the Southeast Pacific off Chile and Peru. It also occurs round the southern coasts of Australia, including Tasmania, and New Zealand.

Behaviour

The school shark is a migratory species. Animals tagged in the United Kingdom have been recovered in the Azores, the Canary Islands, and Iceland. Tagged individuals in Australia have travelled distances of along the coast and others have turned up in New Zealand. The school shark feeds primarily on fish. Examination of stomach contents of fish caught off California showed that they were not fussy eaters and consumed whatever fish were plentiful at the time. Their diet was predominantly

sardines "Sardine" and "pilchard" are common names for various species of small, oily forage fish in the herring family Clupeidae. The term "sardine" was first used in English during the early 15th century, a folk etymology says it comes from the I ...

midshipmen A midshipman is an officer of the lowest rank, in the Royal Navy, United States Navy, and many Commonwealth navies. Commonwealth countries which use the rank include Canada (Naval Cadet), Australia, Bangladesh, Namibia, New Zealand, South Afr ...

flatfish A flatfish is a member of the Ray-finned fish, ray-finned demersal fish order (biology), order Pleuronectiformes, also called the Heterosomata, sometimes classified as a suborder of Perciformes. In many species, both eyes lie on one side of the ...

rockfish Rockfish is a common term for several species of fish, referring to their tendency to hide among rocks. The name rockfish is used for many kinds of fish used for food. This common name belongs to several groups that are not closely related, and ca ...

, and

squid True squid are molluscs with an elongated soft body, large eyes, eight arms, and two tentacles in the superorder Decapodiformes, though many other molluscs within the broader Neocoleoidea are also called squid despite not strictly fitting t ...

. Feeding is done both in open water and near the seabed as sardines and squid are

pelagic The pelagic zone consists of the water column of the open ocean, and can be further divided into regions by depth (as illustrated on the right). The word ''pelagic'' is derived . The pelagic zone can be thought of as an imaginary cylinder or wa ...

animals, while the remainder are benthic species. The school shark is

; its eggs are fertilised internally and remain in the uterus where the developing foetus feeds on the large yolk sac. Males become mature at a length around and females around . The gestation period is about one year and the number of developing pups carried varies with the size of the mother, averaging between about 28 and 38. Pups in the same litter may have different sires, possibly because females are able to store sperm for a long time after mating. The females have traditional "pupping" areas in sheltered bays and estuaries where the young are born. The juvenile fish remain in these nursery areas when the adults move off to deeper waters.

Uses

The

meat Meat is animal flesh that is eaten as food. Humans have hunted, farmed, and scavenged animals for meat since prehistoric times. The establishment of settlements in the Neolithic Revolution allowed the domestication of animals such as chic ...

of the school shark is consumed in

Andalusian cuisine Andalusian cuisine is the cuisine of Andalusia, Spain. Notable dishes include gazpacho, fried fish (often called ''pescaíto frito'' in the local vernacular), the jamones of Jabugo, Valle de los Pedroches and Trevélez, and the wines of Jerez, pa ...

, where it is usually known as ''cazón''. Among recipes are the traditional ''cazón en

adobo or (Spanish: marinade, sauce, or seasoning) is the immersion of cooked food in a stock (or sauce) composed variously of paprika, oregano, salt, garlic, and vinegar to preserve and enhance its flavor. The Portuguese variant is known as . ...

'' in the mainland, and ''tollos'' in the Canary Islands. In

Mexican cuisine Mexican cuisine consists of the cooking cuisines and traditions of the modern country of Mexico. Its earliest roots lie in Mesoamerican cuisine. Its ingredients and methods begin with the first agricultural communities such as the Olmec and M ...

, the term ''cazón'' refers to other species, and is prepared similarly. In the United Kingdom, the flesh is sometimes used in "

fish and chips Fish and chips is a popular hot dish consisting of fried fish in crispy batter, served with chips. The dish originated in England, where these two components had been introduced from separate immigrant cultures; it is not known who created t ...

" as a substitute for the more usual

cod Cod is the common name for the demersal fish genus '' Gadus'', belonging to the family Gadidae. Cod is also used as part of the common name for a number of other fish species, and one species that belongs to genus ''Gadus'' is commonly not call ...

haddock The haddock (''Melanogrammus aeglefinus'') is a saltwater ray-finned fish from the family Gadidae, the true cods. It is the only species in the monotypic genus ''Melanogrammus''. It is found in the North Atlantic Ocean and associated seas where ...

. In

Greek cuisine Greek cuisine (Greek: Ελληνική Κουζίνα) is the cuisine of Greece and the Greek diaspora. In common with many other cuisines of the Mediterranean, it is founded on the triad of wheat, olive oil, and wine. It uses vegetables, oli ...

, it is known as ''galéos'' (γαλέος) and usually is served with

skordalia Skordalia or skordhalia or skorthalia (Greek: σκορδαλιά , also called αλιάδα, aliada/aliatha), is a thick purée in Greek cuisine made of garlic in a base of potatoes, walnuts, almonds or liquid-soaked stale bread mixed with o ...

(σκορδαλιά), a dip made of mashed potatoes or wet white bread, with mashed garlic and olive oil. Before 1937, the school shark was caught in California to supply a local market for shark fillet, and the fins were dried and sold in the Far East. Around that date, laboratory tests on its liver showed that it was higher in

content than any other fish tested. Subsequent to this discovery, it became the subject of a much larger-scale fishery which developed as a result of the high prices obtainable for the fish and its liver. It became the main source of supply for vitamin A in the United States during

World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposin ...

, but was overexploited, populations were reduced, and the numbers of fish caught dwindled. Its oil was replaced by a similar product from the spotted spiny dogfish (''

Squalus suckleyi The Pacific spiny dogfish (''Squalus suckleyi'') is a common species of the Squalidae (dogfish) family of sharks and are among the most abundant species of sharks in the world. This species is closely related to ''Squalus acanthias'' and for many ...

'') and subsequently by lower-potency fish oils from Mexico and South America. The school shark, along with the

gummy shark The gummy shark (''Mustelus antarcticus''), also known as the Australian smooth hound, flake, sweet william or smooth dog-shark, is a shark in the family Triakidae. These small to medium-sized bottom-dwelling sharks are found mostly in, but are ...

, is the most important species in the southern Australian commercial fishery. It is fished throughout its range and heavily exploited.

Conservation status

The IUCN lists the school shark as critically endangered in its Red List of Threatened Species. Although it is widely distributed, it is threatened by

overexploitation Overexploitation, also called overharvesting, refers to harvesting a renewable resource to the point of diminishing returns. Continued overexploitation can lead to the destruction of the resource, as it will be unable to replenish. The term app ...

in many parts of its range, where it is targeted for its liver oil, flesh, and fins. It is caught primarily by

gillnets Gillnetting is a fishing method that uses gillnets: vertical panels of netting that hang from a line with regularly spaced floaters that hold the line on the surface of the water. The floats are sometimes called "corks" and the line with corks is ...

and

longline fishing Longline fishing, or longlining, is a commercial fishing angling technique that uses a long ''main line'' with baited hooks attached at intervals via short branch lines called ''snoods'' or ''gangions''.trawling Trawling is a method of fishing that involves pulling a fishing net through the water behind one or more boats. The net used for trawling is called a trawl. This principle requires netting bags which are towed through water to catch different speci ...

. Pups are sometimes caught inshore and some nursery areas are subject to siltation and their habitat may become degraded. Deep-sea cables and the magnetic field caused by the current flow may disrupt migration routes. In 2010, Greenpeace International added the school shark to its seafood red list. In June 2018 the New Zealand

Department of Conservation An environmental ministry is a national or subnational government agency politically responsible for the environment and/or natural resources. Various other names are commonly used to identify such agencies, such as Ministry of the Environment ...

classified the school shark as "Not Threatened" with the qualifiers "Conservation Dependent" and "Threatened Overseas" under the

New Zealand Threat Classification System The New Zealand Threat Classification System is used by the Department of Conservation to assess conservation priorities of species in New Zealand. The system was developed because the IUCN Red List, a similar conservation status system, had some ...

References

External links

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school shark The school shark (''Galeorhinus galeus'') is a houndshark of the family Triakidae, and the only member of the genus ''Galeorhinus''. Common names also include tope, tope shark, snapper shark, and soupfin shark. It is found worldwide in temperate ...

Fish of the Mediterranean Sea Marine fish of Europe Marine fauna of Oceania Marine fauna of North America Marine fauna of South America Southeastern South American coastal fauna Western North American coastal fauna Marine fauna of Southern Africa Vertebrates of Southern Africa Ovoviviparous fish Vulnerable fish Vulnerable biota of Africa Vulnerable fauna of Asia Vulnerable biota of Europe Vulnerable fauna of Oceania Vulnerable biota of South America

Taxa named by Carl Linnaeus