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Tope: the shark that kept the USA supplied with vitamin A during the war

Until 1937 it was caught in California for its fillets, and its dried fins went to East Asia. Then studies showed, according to the English Wikipedia, that its liver contained more vitamin A than that of any other fish tested — and in the Second World War it became the most important source of vitamin A in the USA. Until it was overfished. This article is about the tope, *Galeorhinus galeus* — in English also school shark, soupfin shark and snapper shark — German Hundshai, Spanish cazón (also tiburón vitamínico), Italian canesca (GBIF), French requin-hâ, Portuguese tubarão-perna-de-moça (GBIF), Dutch ruwe haai, Danish and Swedish gråhaj, Norwegian gråhai (GBIF), Finnish harmaakoirahai, Russian суповая акула, Turkish camgöz (GBIF), Greek Γαλέος, Croatian butor, Albanian peshk qen (GBIF), Japanese イコクエイラクブカ and Arabic جلاد كلبي (Wikidata); in Slovenian we found no name of its own in either Wikidata or GBIF. It is a predator of temperate seas, rare in the Mediterranean — and the IUCN now lists it as critically endangered. Here is how to identify it, how far it travels and why, if it bites, it belongs back in the water.

A name from antiquity

It was described by Carl Linnaeus in 1758 as *Squalus galeus* (the English Wikipedia). According to FishBase, the species name goes back to the Greek galeos, which Aristotle used for a small shark — sometimes translated as weasel, perhaps because of the pointed snout, the nimble movements or the predatory feeding of small sharks. *Rhinus*, according to FishBase, is an old name for sharks, derived from rhine, the rasp — an allusion to the rough skin. According to the English Wikipedia, the tope is the only living species in its genus, and the genus goes back at least to the early Eocene. FishBase also explains the English name soupfin: its fins end up in soup — and the Russian суповая акула literally means soup shark.

How to identify it

FishBase describes it as a large shark of the family Triakidae with a long, pointed snout, a large mouth and small, blade-like teeth. According to the English Wikipedia, the teeth in the upper and lower jaws look the same: small, flat, triangular, serrated, with a notch and angled backwards. The first dorsal fin is triangular and sits just behind the pectoral fins; the second dorsal fin is about as large as the anal fin and stands directly above it. The most striking feature is the tail fin: according to FishBase, its terminal lobe is as long as the entire rest of the fin. It is grey above (dark bluish grey according to the English Wikipedia) and white below; juveniles have black markings on the fins.

  • Size: according to FishBase, at most 193 cm in males and 195 cm in females, commonly 160 cm; the English Wikipedia gives just under 2 m.
  • Weight: according to FishBase, the heaviest published weight is 44.7 kg.
  • Age: according to FishBase, up to 55 years — a very slow life for a shark of this size.

Where it lives

According to FishBase, it lives worldwide in cold to warm temperate seas, between 70° North and 58° South, from the surface down to 1,100 m, but mostly between 2 and 471 m. It stays mainly above the bottom of continental shelves and upper slopes — but it also ventures into the open sea: FishBase reports that it is often caught on drifting tuna longlines over deep water. The English Wikipedia gives a water temperature of 10 to 20 °C and lists its range: the Northeast Atlantic and the Mediterranean, where it is rare; the Southwest Atlantic from Patagonia to southern Brazil; Namibia and South Africa; the Northeast Pacific from British Columbia to Baja California; Chile and Peru; southern Australia including Tasmania, and New Zealand.

A shark that travels far

According to FishBase, it moves in small schools — hence the English school shark — which migrate widely in the higher latitudes of its range; in some areas the animals segregate clearly by size and sex. Tagging shows how far: according to the English Wikipedia, topes tagged in Great Britain were recovered off the Azores, the Canaries and in Iceland. Animals tagged in Australia covered up to 1,200 km along the coast, others turned up in New Zealand — and conversely, according to FishBase, many animals tagged in New Zealand were recaptured in Australia.

What it eats

According to FishBase, it eats fish — from the bottom as well as from open water — plus crustaceans, cephalopods, worms and echinoderms; the English Wikipedia mainly names fish. Stomach contents from California included sardines, midshipmen, flatfish, rockfish and squid. According to the English Wikipedia, topes living on reefs prefer barracuda — and the stomach contents of a fossil relative, *Galeorhinus cuvieri*, suggest that this predator–prey relationship has existed for at least 50 million years. FishBase puts it at trophic level 4.3.

A year’s pregnancy, dozens of pups

The tope gives birth to live young, which according to FishBase feed only on yolk in the womb. According to FishBase, a litter comprises 6 to 52 pups — the larger the mother, the more —, each 30 to 36 cm long; gestation lasts about twelve months. According to the English Wikipedia, the pups of one litter can have different fathers, because females store sperm for a long time. To give birth, females seek out sheltered bays and estuaries; the young stay there while the adults move into deeper water. According to the English Wikipedia, males reach maturity at 8 to 13 years, females only at 11 to 18. FishBase rates its resilience as low: a population needs 4.5 to 14 years to double.

The liver that went to war

According to the English Wikipedia, in the Second World War the tope was the most important source of vitamin A in the USA until it was overfished; its oil was then replaced by that of the spiny dogfish and later by weaker oils from Mexico and South America. It is still used today: FishBase lists its meat, the liver for squalene oil, the fins for soup and fishmeal. In Andalusia it is called cazón in the kitchen, in the Canaries tollos, in Greece galéos, and in Britain, according to the English Wikipedia, it sometimes replaces cod or haddock in fish and chips. The Māori call it kapetā: according to the English Wikipedia, communities gathered at Rangaunu Harbour, because there it could be caught for two days — and they mixed the oil from its liver with red ochre to make cosmetics.

Why it belongs back in the water

The IUCN lists it worldwide as critically endangered (Critically Endangered; assessed on 14 February 2020 according to FishBase). As causes, the English Wikipedia names overfishing for liver oil, meat and fins, mainly with gillnets and longlines, and damage to its nursery grounds. FishBase rates its vulnerability to fishing as very high and lists it under Appendix II of the Bonn Convention (CMS). In England, the Tope Order has applied since 6 April 2008: within its scope, any fishing for tope other than with rod and line is prohibited, and topes caught with rod and line may not be landed in England. According to FishBase it is harmless to humans, and FishBase lists it as a game fish. Which rules apply on your water today is something you check yourself before you head out — with the harbour office, the fisheries authority, your guide or skipper. If a tope takes the hook, release it as gently as possible in the water.

Four contradictions, left standing

  • How deep does it go? FishBase: down to 1,100 m, mostly 2 to 471 m — and elsewhere on the same page down to 550 m. The English Wikipedia: down to about 800 m. The German Wikipedia: down to about 550 m.
  • Bottom fish or open-ocean fish? The English Wikipedia: mainly close to the bottom. FishBase: mainly above the bottom, but also pelagic in the open sea — often on drifting tuna longlines.
  • When is it mature? The English Wikipedia: males at around 135 cm, females at 150 cm. FishBase: on average 144.1 cm, with a range of 120 to 185 cm.
  • How many pups? FishBase: 6 to 52. The English Wikipedia: on average 28 to 38 — both say that the number grows with the size of the mother.

Three names that lead to the wrong fish

  • “Cazón”. This is the Spanish name of the tope — but according to the Spanish Wikipedia, similar species such as the smooth-hounds (genus *Mustelus*) are also sold as cazón, and in parts of the Gulf of Mexico and the Caribbean even the young of other sharks go by that name. Anyone eating cazón en adobo cannot be sure which shark is on the plate.
  • “Émissole”. GBIF also lists this French name for the tope, but according to the French Wikipedia, émissole is an ambiguous name that mainly refers to the smooth-hounds of the genus *Mustelus*. The French name of the tope is requin-hâ.
  • “Hondshaai”. It sounds like Hundshai, the German name of the tope, but it is not: GBIF lists Hondshaai for the small-spotted catshark, *Scyliorhinus canicula*, to which this series devotes a group of its own. The Dutch name of the tope is ruwe haai.

That leaves the question every article in this series starts with: when. Habitat, prey and habits are set out above, and they are fixed. Everything else changes every day — light, wind, current, water temperature —, and that is exactly where it is decided whether a day at sea is worth it. That is what StrikeAhead works out: it takes the conditions on your water and tells you when the trip is worth it. And because you cannot know an unfamiliar area, its edges and its rules from day one, StrikeAhead Pathfinder tells you who to go out with: curated guides and skippers, personally vetted before listing — licence and insurance —, with verified catches instead of promo photos, no paid ranking and, for you as an angler, no booking fee. The app tells you when, Pathfinder tells you who with.