Tiger sharks (Galeocerdo cuvier): – have teeth shaped like those found on a circular saw? – can travel thousands of miles between continents ? – can have between 10 & 82 pups ? – require bays or estuaries as nursery aeras ? – can take up to 18 years to reach maturity ? Basking sharks (Cetorhinus maximus) : – are long distance travellers ? – filter around 2000 tons of water a day? – can weight up to 1800 kgs ? – are the second largest fish in the sea ? – swim by moving their entire body from side to side, not just their tail ? – spend a lot of their time at the surface, hence their nickname (confusingly) is “sunfish” ? – have hundreds of tiny ineffective teeth ? Tresher sharks (Alopias sp.): – have tails so large they account for more than a third of their body weight and half of their total length? – are solitary and are rarely seen near the shore ? – use their tails to herd prey, and even to stun sardines or mackerels ? – can leap out of the water if threatened or provoked? – are ovoviviparous (eggs develop and hatch in the uterus, and continue to develop until birth) and have young that can feed on weaker siblings in the womb – known as intra-uterine cannibalism ? – have very big eyes to help to see in the dark ? Great white sharks (Carcharodon carcharias): – females are generally larger than males ? – males reach maturity at 3.5–4.0 meters (11–13 ft), and females at 4.5–5.0 meters (15–16 ft) ? – have an average mass of 680–1,100 kgs (1,500–2,400 lb) ? – reach sexual maturity at around 12-15 years of age? – have an gestation period about 11 months ? – are ovoviparous and that the shark’s pup’s powerful jaws begin to develop in the first month? – are now considered endangered as no accurate population numbers are available? Sharks taken during the long interval between birth and sexual maturity never reproduce, preventing population recovery.
- Nausicaà : “sélection” non naturelle
- 17 espèces de raies et requins classées menacées d’extinction
- La Réunion : massacre de petits requins à la Pointe au sel / slaughter of small sharks on the West coast
- Nausicaá : 28 requins marteaux morts sur 30 individus prélevés dans la nature en 2011 et 2018 pour le centre de Boulogne-sur-mer
- Décembre 2018 : notre blog fait peau neuve!