# Shark (fish)

Sharks are fish that constitute more than 500 known species and belong to the subclass Elasmobranchii. Sharks occur in all of the world's seas, and the vast majority of species live exclusively in saltwater. The two shark species with the most documented cases of attacks on humans are the great white shark and the tiger shark. The two physically largest shark species are the whale shark and the basking shark.

## Quotes

* The life span of sharks can be determined by keeping them in captivity, by tagging, or, more commonly, by counting growth rings in their vertebrae or spines and estimating the age. Only a few species of sharks have been kept in captivity for long periods of time. When sharks have been captured young and have lived in captivity for prolonged periods, a rough idea of their potential life span can be obtained. Although keeping sharks in captivity for many years is a difficult feat, some sharks have lived for decades in captivity, indicating that they have long life spans. Unfortunately, most aquaria do not keep accurate records of the life span of their captive sharks, and valuable data on the longevity of sharks is lost.
** José I. Castro, The Sharks of North America. Oxford University Press. 2011. p. 6. ISBN 978-0-19-539294-4.
* I have heard from Dr. Allan of Forres, that he has frequently found a Didion, floating alive and distended, in the stomach of the shark; and that on several occasions he has known it eat its way, not only through the coats of the stomach, but through the sides of the monster, which has thus been killed. Who would ever have imagined that a little soft fish could have destroyed the great and savage shark?
** Charles Darwin, The Voyage of the Beagle. 1909. p. 24. (1st edition 1839; Didion antennatus is a synonym for Chilomycterus antennatus.)
* we used to think of sharks as bad guys — like the only good shark was a dead shark. And “man-eaters” — they used to tell me to “watch out for the man-eaters”...But actually, sharks have to worry about humans eating sharks. We consume millions of sharks...we’re shark-eaters. If 50 people a year get bitten by sharks, that’s big news. But consider the number of shark deaths that we cause every year. Maybe as many as on the order of 80 million sharks are taken, largely for shark fins for the soup.
** Sylvia Earle Interview (2018)
* When the young dog-fish is completely formed, the yolk remains attached to the belly by a long chord, consisting of blood vessels, and the fish swims about in the surrounding jelly with this attached to it. If the bag is torn, and the fish is taken out and put into the water, it swims about, but if the vessels going to the yolk are wounded, the fish immediately dies.
** Everard Home, (1810)"Article XII. On the Mode of Breeding of the Ovo-viviparous Shark, and on the Aëration of the fætal Blood in different Classes of Animals". Philosophical Transactions of the Royal Society of London: 205–222. (quote from p. 209)
* ... While sharks kill an average of four humans a year, humans kill 100 million sharks each year. ... While recreational fishing is doing considerable harm to the shark population around the world, commercial fishing is decimating it. Sharks are harvested throughout the world for their meat, skin, fins, liver, and cartilage. ... Specifically sharks are killed as a by-product of the $40 billion tuna industry, which provides the United States with enough tuna to feed every American 2.6 pounds per year.
** William McKeever, "Introduction. Man Bites Shark". Emperors of the Deep: Sharks—The Ocean's Most Mysterious, Most Misunderstood, and Most Important Guardians. HarperCollins. 2019. ISBN 978-0-06-288034-5.

## External links

* Encyclopedic article on Shark on Wikipedia
* The dictionary definition of shark on Wiktionary