Four Hundred And Seventy

There are over 470 species of sharks and they have been living on Planet Earth for 420 million years.

The smallest shark - the dwarf lantern shark - is only 17 centimeters (6.7 inches) in length, while the whale shark is the largest specie in the world, with approximately 12 meters (39 feet).

Sharks live in all oceans down to depths of 2,000 meters (6,600 feet). Usually, they do not live in freshwater with the exception of the bull shark and river shark.

Teeth and jaws of sharks are deadly, but only the great white, oceanic white tip, tiger and bull sharks are responsible for fatal attacks on humans. The International Shark Attack File reveals that between 1580 and 2012, up to 2569 people lost their lives due to shark attacks.

USA and Australia are the most sharks infested countries in the world. From year 1580, a total of 510 shark attacks killed 144 people in Australia. In the United States, 1022 attacks have already caused 36 deaths.

Florida and California have been suffering more than any other US state. With a total of 772 attacks, both territories have claimed 21 lives. Maui, Oahu and Kauai record all fatalities (8) ever in the Hawaiian Islands.

Cartilage

Chondrichthyes are called cartilaginous fish. You can see the clear difference from their cartilage frame. Sharks, skates and rays are the main examples of Chondrichthyes fish. This type of fish usually does not have a connection between the upper jaw and skull. It gives them great difficulty as well to move it independently. The main structure of Chondrichthyes fish is comprised of ten cartilage parts. Chondrichthyes fish also have eyelids to protect their eyes and at the same time, Chondrichthyes fish usually do not have ribs and bone marrow. The dermal dental structure is also slightly different than Osteichthyes fish. Chondrichthyes fish and their red blood cells produced in the spleen as the two lobes of the fin are not equal in size. The size of the two lobes of the fin is important as they give them sharp mobility in the water. The fin is parallel to the longitudinal axis of the main body in Chondrichthyes fish. Chondrichthyes' fins that are parallel to the longitudinal axis of the main body basically helps them to balance and move fast in the water. Chondrichthyes are often called living fossils while many scientists believe that their evolution is in progress for the past 420 million years

Read more at: Difference between Chondrichthyes and Osteichthyes http://www.stepbystep.com/difference-between-chondrichthyes-and-osteichthyes-101533/

Sharksafe

Stellenbosch University scientists have developed an eco-friendly shark barrier which can be used as an alternative to a shark net.

The barrier is called Sharksafe.

Shark nets were introduced to reduce the number of shark attacks on swimmers but they have resulted in the death of other sea animals including dolphins and turtles.

Countries including Australia, Japan and the US are looking at alternatives to shark nets while in Cape Town new shark exclusion nets which can be removed daily have also been developed.

Professor Conrad Matthee, head of the Department of Botany and Zoology, said shark numbers had decreased by up to 90 percent over the past 20 years, “particularly the number of great white sharks”.

“Sharks are top predators and if they were to be taken out of the ecosystem, the latter will be disrupted. 

Mya

The megalodon was the largest shark of all time. Its scientific name is Carcharodon megalodon. It lived from 20 to 1.5 million years ago (mya). This giant of a shark was a huge version of the current great white shark (Carcharodon carcharias). Megalodon had teeth, which are among the largest ever found, over 18 cm (7 inches) long. Fossil remains suggest that this giant shark reached a maximum length of 15.9–20.3 metres (52–67 ft) and weigh over 60 tons.

Sixty-Seven

Many animals that formerly lived on earth have modern analogs, animals living today that look and behave very like those ancient animals, though they might not be direct descendants. It’s as though the giant cats, bears, wolves, and sharks of the world recur again and again, slightly reconfigured each time. One ancient mega-tooth shark, Megalodon (mega for big, odon for tooth) has a small analog in the great white shark.

Great white sharks are big as predatory sharks get today, growing to 20-feet long, weighing up to 4,200 pounds (2.1 short tons). Some older records of much larger great whites are based on inferences of size and not direct measurements. Body shape and weight of these sharks help estimate the size of fossil Megalodon skeletons. Compared to Megalodon, they are in the second tier for size: Megalodon grew to 67 feet long, and a weight of 114 short tons.

A King Is Born

A comet sailing through the inner system make its closest approach to the sun and will be at its brightest at sunset tonight, but the glare of twilight may make it tricky to see.

Pan-Starrs will be 28 million miles (45 million kilometres) from the surface of the sun when it swings around the star today, and should be bright enough to see without the aid of telescopes or binoculars, weather permitting. But the comet is also appearing low on the western horizon at sunset so some planning is needed to spot the celestial wanderer with the naked eye tonight.

"Look too early and the sky will be too bright," said Rachel Stevenson, a NASA Postdoctoral Fellow at the agency's Jet Propulsion Laboratory in Pasadena, Calif. "Look too late, the comet will be too low and obstructed by the horizon. This comet has a relatively small window."

Rottnest

Two years ago, a sport fisherman caught a pair of rare sharks off Rottnest Island in Western Australia. The duo, a male shark about 3.3 feet (1 meter) long and a pregnant female about 3.9 feet (1.2 m) long, looked different from the sharks that normally prowl the Australian waters. The female was carrying 22 pups.

The fishermen gave the sharks to ocean researchers at the University of Western Australia. After analyzing the sharks' DNA, the team concluded that the sharks were mandarin dogfish sharks, which are normally spotted only in the waters off Indonesia, Japan and New Zealand.

Extinction

Sharks risk being driven to extinction due to overfishing, with almost 100 million killed each year, scientists have warned.

Many species of shark need better protection to prevent their extinction within coming decades, researchers warned in advance of a global conference on the trade in threatened species.

The Convention on International Trade in Endangered Species (Cites) will consider greater protection of vulnerable sharks, including porbeagles, oceanic whitetip and three types of hammerhead to preserve their populations.

Sharks are caught for their fins for use in shark fin soup, a delicacy in Asia. The fins are cut off with the dead carcass being thrown back into the sea. Sharks grow slowly and take years to reproduce, which makes them vulnerable to overfishing.

The researchers estimated that global reported catches, unreported landings, discards and sharks caught and thrown back after their fins were cut off – a process known as finning – added up to 97 million fish caught in 2010.

Summit

DELEGATES from around the world have gathered in Thailand to work out a mechanism to restrict trade in wildlife and save endangered animals, including sharks, manta rays, polar bears, elephants and rhinos.

About 2,000 delegates from 178 member nations of the Convention on International Trade in Endangered Species of Wild Fauna and Flora are in Bangkok for the 16th CITES conference, held every three years.

The delegates are to consider dozens of proposals on increased or decreased trade protection for endangered species by listing them on Appendix I, which prohibits all traffic in a species, or Appendix II, which restricts trade to ensure it is sustainable.

Conservationists are calling on Australia to take a stand to protect several shark species threatened by the multi-million dollar shark fin trade to Asia, especially China.

Guilty

{EAV:a24bf918a799496e}

The Department of Agriculture, Forestry and Fisheries (DAFF) welcomes the guilty verdict and stiff sentence handed down to Leon Bekker in the Mossel Bay Magistrate’s Court last Friday afternoon, 1 February 2013.

Bekker, who caught, landed and disturbed a great white shark (Carcharodon carcharias) – a protected species on 11 March 2011 in the Mossel Bay area, was found guilty and fined R120 000 or months imprisonment, suspended for 5 years.

What makes this case so remarkable is the fact that this is the first great white shark case and conviction in any South African court as South Africa is also the first country to impose legislation in protecting Great White Sharks.

  

Mandarin

A rare shark couple found for the first time off the coast of Australia may force a rethink of the species' range.

Two years ago, a sport fisherman caught a pair of rare sharks off Rottnest Island in Western Australia. The duo, a male shark about 3.3 feet (1 meter) long and a pregnant female about 3.9 feet (1.2 m) long, looked different from the sharks that normally prowl the Australian waters. The female was carrying 22 pups.

The fishermen gave the sharks to ocean researchers at the University of Western Australia. After analyzing the sharks' DNA, the team concluded that the sharks were mandarin dogfish sharks, which are normally spotted only in the waters off Indonesia, Japan and New Zealand.

Read more: http://www.businessinsider.com/rare-sharks-found-in-australian-waters-for-the-first-time-2013-3#ixzz2MKSaK2gI

 

Enormous

A shark possibly four metres long killed a swimmer near a popular New Zealand beach on Wednesday, then disappeared after police attempting to save the man fired gunshots at the enormous predator.

Muriwai Beach near Auckland was closed after the fatal attack, one of only about a dozen in New Zealand in the past 180 years.

Pio Mose, who was fishing at the beach, told The New Zealand Herald he saw the swimmer struggle against the “huge” shark. He told the man to swim to the rocks, but it was too late.

“All of a sudden there was blood everywhere,” Mose said. “… I was shaking, scared, panicked.”

Mako

South Australian Research and Development Institute (SARDI) environment and ecology program research scientist Paul Rogers said mako sharks were known to travel vast distances and several tagged as part of the current program had followed the same route.

"He is the fourth shark that has been up there in the past five years," he said.

"It is a fairly consistent pattern we are starting to detect with this species. It does tend to happen in late winter, but there have been sharks that have broken that pattern."

Mr Rogers said Morry weighed about 80kg when tagged and is believed to be aged between eight and 10 years old.

While the reason for their passage north was not yet known, the sharks were following a consistent pathway along the slope of the Continental Shelf until they were off Cape Leeuwin, the most southerly point of WA.

They then ventured into ocean waters, possibly visiting sea mountains and mid-ocean ridges to navigate and locate food.

Another mako tagged off Port MacDonnell in May 2009 swam 24,700km before its tag stopped transmitting in November 2010.

Unprovoked

Shark attacks in the U.S. reached a decade high in 2012, while worldwide fatalities remained average, according to the University of Florida's International Shark Attack File report released today.

The U.S. saw an upturn in attacks with 53, the most since 2000. There were seven fatalities worldwide, which is lower than 2011 but higher than the yearly average of 4.4 from 2001 to 2010. It is the second consecutive year for multiple shark attacks in Western Australia  and Reunion Island  in the southwest Indian Ocean, which indicates the localities have developed problematic situations, said George Burgess, director of the file housed at the Florida Museum of Natural History on the UF campus.

“Those two areas are sort of hot spots in the world – Western Australia is a function of white shark incidents and Reunion is a function most likely of bull shark incidents,” Burgess said. “What I’ve seen in all situations when there’s been a sudden upswing in an area is that human-causative factors are involved, such as changes in our behavior, changes in our abundance, or an overt shark-attracting product of something that we’re doing.”

Eighty unprovoked attacks occurred worldwide, slightly more than 2011. Four attacks were recorded in South Africa, three of which resulted in death, which is higher than its recent average of one fatality per year. Australia had an average year with 14 attacks and two fatalities, despite the media attention regarding incidents in Western Australia that resulted in a government-sanctioned culling hunt for endangered white sharks.

Drones

Drones with infra-red technology and high-tech cameras could be used to spot sharks off WA beaches, which have been ranked as a global hotspot for fatal attacks, according to a Perth shark expert.

Surf Life Saving WA statistics show 101 sharks have been seen from the metropolitan helicopter this season, including nine great whites, 57 tiger sharks, two bronze whalers, 11 hammerheads and a whale shark.

But there could have been more than 500 sharks off the metropolitan coast, with a NSW Department of Primary Industries report finding helicopter surveys spotted only 17.1 per cent of sharks.

Wildlife Marine founder and director William Robbins, who wrote the report while working for the NSW Government, said people in helicopters struggled to spot sharks that were more than 2.5m below the surface or more than 250m from the aircraft.

Dr Robbins said it would be worth investigating whether aerial drones, such as those used by the military, could be equipped with infra-red sensors to look further into the water than human observers.

"White sharks in particular, they actually have a body temperature that's slightly higher than the surrounding water that they're swimming in," he said.