The School shark (Galeorhinus galeus) is a shark belonging to the family Triakidae, and the only member of the genus Galeorhinus. Common names also include the Tope shark and Soupfin shark. However, the name “Soupfin” is not encouraged. It is found worldwide in temperate seas at depths down to about 2,625 feet. It is ovoviviparous. The School shark is caught in fisheries for its flesh, its fins, and its liver, which has a very high vitamin A content, and therefore classified as vulnerable.
Family: Triakidae – Houndsharks
Genus: Galeorhinus
Species: galeus
Phylum– Chordata
Class– Chondrichthyles
Common Name– Ground Sharks
Family– Triakidae
Common Name– Houndsharks
Genus– Galeorhinus
Species– galeus
Status: IUCN Red List VULNERABLE
Average Size and Length: The size of the School shark varies by location or region. They are born between 30-40 cm/11.8 inches-1.3 feet. Mature males have been measured between 120-170 cm/3.9-5.6 feet. Mature females have been measured between 130-185 cm/4.3-6.1 feet. The maximum recorded for a male has been 175 cm/5.7 feet and 195 cm/6.4 feet for a female.
Teeth and Jaw: The large mouth is long, arched or 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, or blade-like. The labial furrows are somewhat long.
Head: It has a long nose; the snout is elongated. It does not have obvious anterior nasal flaps or sub-ocular ridges. The eyes are large oval and elongated with nictitating membranes. The spiracles are small.
Tail: It has an extremely long terminal caudal lobe with a notch, which is half the dorsal caudal margin.
Demographic, Distribution, Habitat, Environment and Range: The School shark can be found in world-wide temperate waters. It is most plentiful in cold to warm temperate continental seas from the surf-line to extremely shallow water, to waters that are well offshore, but not oceanic, near the bottom between 7-1,545 feet (some reports down to 2,625 feet). It can be found in the Northeast Atlantic and Mediterranean Sea, where it is uncommon and the Southwest Atlantic where it can be found between Patagonia and southern Brazil. It also can be found around the coast of Namibia and South Africa. It is present in the Northeast Pacific where it can be found between British Columbia and Baja California, and in the Southeast Pacific off Chile and Peru. It has also been seen around the southern coasts of Australia, including Tasmania, and New Zealand (subtropical, 68°N – 55°S). They are considered benthopelagic and oceanodromus.
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 746 miles along the coast and others have turned up in New Zealand. It has been recorded distances up to 994 miles during some of these seasonal migrations. Pregnant females are known to move into shallow bays and estuaries to give birth, then return to offshore feeding grounds. Juvenile sharks will remain in nursery grounds for up to two years, and then join schools of the immature sharks on other locations.
Diet: They are mainly opportunistic predators feeding on bony fish and invertebrates in midwater as well as benthic, down near the seabed. Examination of stomach contents of fish caught off California showed that they consumed whatever fish were plentiful at the time. Their diet was predominantly sardines, midshipmen, flatfish, rockfish, and squid.
Predators include larger sharks like the Great White shark and the Sharpnose Sevengill shark, and maybe even marine mammals.
Aesthetic Identification: The School shark is streamlined, slender and shallow-bodied. The last two of the five gill slits are over the pectoral fins. The dorsal side is dark bluish or greyish, and the ventral side is counter-shaded white. Young sharks have black markings on the fins. The first dorsal fin is triangular with a straight leading edge and is set just behind the pectoral fins. The second dorsal fin is much smaller than the first dorsal fin and is about as large as the anal fin, and it is set directly above it.
Biology and Reproduction: They are ovoviviparous without a yolk-sac placenta. They can have anywhere from 6-52 (average 28-38) pups per litter with a gestation period of about a year. The larger the mother, the larger the litter size. Pups in the same litter may have different sires, possibly because females are able to store sperm for a long time after mating. They have very low biological productivity. The maximum age is though to be around 60 years. Female maturity is greater than 10 years.
Vert. (precaudal) 79; (total) 127.
Behavioral Traits, Sensing and Intelligence: They can occur in small schools. They are partly segregated by sex and size, especially in higher latitudes where they are seasonally migratory. Females give birth in shallow nursery areas, where young sharks remain there for about 2 years.
Speed: The School shark is an extremely active, strong swimmer that swims long distances. They are capable of swimming up to 35 miles per day.
School Shark Future and Conservation: They are currently vulnerable. In 2010, Greenpeace International added the School shark to its seafood red list. The School shark is fished all over the world for its meat, liver oil and of course fins. It is also fished by anglers for sport. Unmanaged fisheries have depleted its population in many regions. The School shark and the Gummy shark are the most important species in the southern Australian commercial fishery. 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.
The meat of the school shark is consumed in Andalusian cuisine, where it is usually known as cazón. Among recipes are the traditional cazón en adobo in the mainland, and tollos in the Canary Islands. In Mexican cuisine, the term cazón refers to other species, and is prepared similarly. In the United Kingdom, the flesh is sometimes used in “fish and chips” as a substitute for the more usual cod or haddock. In Greek cuisine, it is known as galéos (γαλέος) and usually is served with skordaliá (σκορδαλιά), a dip made of mashed potatoes or wet white bread, with mashed garlic and olive oil (NOAA: Northeast Fisheries Science Center).
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 vitamin A 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, 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) and subsequently by lower-potency fish oils from Mexico and South America (“Fish Bulletin No. 64. The Biology of the Soupfin Galeorhinus zyopterus and Biochemical Studies of the Liver“. Repositories.cdlib.org).
School Shark Recorded Attacks on Humans: Not a threat to humans.