Eusphyra+Blochii


 * Slender Hammerhead **

//Kingdom:// Animalia //Phylum:// Chordata //Class:// Chondrichthyes //Order:// Carcharhimformes //Family:// Sphyrnidae //Scientific name:// Eusphyra blochii

The Slender Hammerhead was assesed in 2003 and was put on the endangered species list due to over-fishing. There is no scientific data on its status and biological data is pretty much unknown, but based on lesser-known accounts and market surveys the population is assumed to have declined and is assessed as Near Threatened. In Australia it is only a small component of commercial catches, the population is considered to be relatively healthy and is assessed as Least Concern. If the over-fishing were to continue, they may become listed as Highly Threatened.

The Slender Hammerhead is found in the waters of the Indo-West Pacific: from the Persian Gulf to the Philippines, north to China and south to Australia. Thes sharks are found between 0 and 30 degrees latitude in the Indian Ocean. The Indian ocean's temperature ranges from 15 to 28.5 degrees celcius and the salinity is between 34.0 to 36.0 PPT. Their migratory patterns are currently unknown but researchers do know that they travel in schools into shallower water seasonally which leaves their young threatened by commercial fisherman.

The currents found in the Indian Ocean are the North Equitorial, South Equitorial, South Indian, W. Australia and the Equitorial Counter. The average tidal range in the Cocos Islands, which is found in the Indian Ocean, is about .58 meters. The Indian Ocean has natural occurences such as a few volcanoes, tsunamis, earthquakes, seafloor spreading in the Southern Indian Ocean, and subduction zones caused by earthquakes. (Some examples of volcanoes are Piton de la Fournaise on La Réunion island and Karthala volcano on the Comores.)

Eusphyra Blochii, or slender hammerhead, is rightly named after its hammer-like appearence occuring at the head with the eyes and nostril positioned at the tip of hammer.

-Back predominantly grey/brownish, underside white/light grey with two dorsal fins -Sizes range from 0.9-6 m long (3-20 ft) -Many species are migratory and are known to form schools containing hundreds of individuals -Average lifespan in the ocean: 20 to 30 years

Female hammerheads ten to have 4 to 42 young per litter with a gestation period of 10-12 months. The pups fend for themselves after birth and most survive. These hammerheads feed on aother sharks, cephalopods, gastropods, bivalves, and crustaceans such as shrimp, mantis shrimp, brachyurid crabs, lobsters, barnacles, and isopods. These sharks specifically but do not feed on marine mammals or other very large marine vertebrates. Hammerheads are not hunted by any creatures in the ocean; just killed for meat and other supplies by humans. Studies done to see their natural predators have been inconclusive; humans may be the only reason for extinction. Hammerheads are important to humans because they supply oil, meat and skin to tradespeople mainly in the tropics. The only real human interaction with these species is commercial fishing of them for profit. Humans are the reason they are even considered threatened, although it is not presently a huge concern.

Hammerheads and other sharks share mutualistic relationships with the Barberfish in that the fish eats parasites off of the shark and gains a mean while the shark is rid of parasites that infect it. Scientists and researchers have no idea what the population could be due to overfishing and migration of these hammerheads.

The hammerhead's unique anatomy and abilities consist of: -Hammer-shaped head that helps hunt their prey, with an eye and nostril on each side of the head -Their head shape also helps to pin down food such as rays, making it easier to catch. -Their eyesight is amazing in the blue and green spectrum and unlike most creature in the ocean, they can see red. (They have adapted this way from living in the deepest parts of the oceans.) -Another superior sense hammerheads have is their hearing; hammerheads can hear sounds just as we can. But their most keen ability is hearing is low frequency vibrations mainly from wounded fish. -They can smell chemicals such as blood in concentrations as low as one part per million, and track the animals for miles. Although the slender hammerhead's population numbers are unknown because of instability, hammerhead numbers in general have decreased 99.99% in the past 20 years. They are facing extinction due to over-fishing mainly in Asia. Activists in Austraia are calling on law enforcenment officials to criminalize the capture of these sharks and many more species in the Coral Reefs. Also, this area needs to be protected for other fish and mammals facing extinction over the next few years. If it were up to me, I would ban fishing of all sharks in general and make the punishment more serious than a fine. Also i would ban the selling of fins, oils and other products of these animals. Lastly i would continue and expand on the projects to raise these hammerheads and other sharks in captivity to help raise population numbers. All of these marine species face extinction unless we eliminate pollution and restrict fishing of these species especially.

-What types of natural occurances are found in the Indian Ocean?

-In the Indian Ocean, what degrees latitude are these sharks found at?

-What is the average lifespan of a slender hammerhead shark?

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