Sharks in the Canary Islands
To the date, there have been records of some 50 shark species in the Canary Islands, however it is true that the vast majority live either in deep areas -the nurse shark, the gulper shark, the bluntnose sixgill shark, the spiny dogfish, and the sharpnose sevengill shark amongst others-, or in shallow waters away from the coastline -the shortfin mako shark and the blue shark-, so they never interact with humans except for when we fish for them. Even so, some species which are considered to be dangerous can be found in coastal waters, such as the tiger shark (Galeocerdo cuvier), the silky shark (Carcharhinus spp.), the hammerhead shark (Sphyrna spp.) and the bigeye thresher shark (Alopias spp.). Cases of attacks are very rare, however, and the few that have been reported were related to actions caused indirectly by men and were not serious. Biologists cannot come up with a clear explanation for the fact that species that normally cause attacks in other areas do not behave in that way in the Canarias. This abnormal behaviour is without a doubt a great competitive advantage of the beaches and bathing areas in our islands. On the other hand, the extremely dangerous white shark (Carcharodon carcharias), so widely feared in other maritime areas -mainly temperate and subtropical- is exceptionally rare in the Canary Islands and the scarce records there are -3- have occurred far from the coast in the eastern islands. It is believed that the absence in the islands of one of their preferred preys, the seal, may have something to do with this.
By the seashore, the Atlantic angel shark (Squatina squatina) and the houndshark (Mustelus mustelus) are more frequently seen, mainly in sandy sectors. Some females go into sheltered beaches at night to give birth there.
These are harmless animals and they ought not to be disturbed. Houndsharks have blunt teeth and are unable to bite the bathers. In the case of the angel shark, which does have sharp teeth, some cases have been reported of these animals biting swimmers in the feet when the latter stepped on their offspring in some beaches, but these accidents have always been little or not important at all. Species such as the silky shark and the hammerhead shark can be found near the coast and they will exceptionally swim into the beach, but that is a very rare phenomenon. Nowadays, the populations of the above species are very small after having been remarkably decimated through fishing activities, and can only very occasionally be seen, especially in far-away areas such as Anaga and Teno in Tenerife.
Sharks are predators placed in the top tier of the food chain, which in turn means that their populations cannot be numerous. In addition their growing rate is quite slow, their reproductive cycle starts late in life and female gestation periods are rather long, reaching sometimes 20 months, and they give birth to few babies. This evolutionary self-regulation makes sharks extremely vulnerable to fishing activities, with greater risks around intense trawling and long-line fishing areas. The situation has become so serious that it has been deemed necessary to proceed to the protection of certain species which it is now prohibited to fish. In Canarian waters, hammerhead sharks, bigeye thresher sharks and Atlantic angel sharks have been protected in this way. Given that trawling is not practiced in the Canarias, there is a numerous population of Atlantic angel sharks, which is currently highly valued due to it being increasingly rare in European coasts.
We now know that the correct preservation of shark populations guarantees in turn the good condition of ecosystemic structures. Therefore, it is important to put into value the role played by these animals -which films have exclusively and falsely depicted as dangerous monsters- in the organization of marine life, and make understood that they are not as dangerous. A region such as the Canarias can be proud to boast a wealth of shark species and at a time have safe coasts and beaches for swimmers and divers. With the appropriate protection measures in place, they will become a great attraction in our natural world.
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