Unicorn Shark?

6:32 PM - 10/5/2006 - comments {0} - post comment

how Fast can a Shark swim?

How Fast Can a Shark Swim?

Sharks typically swim with the even, liquid grace of a creature completely at home with its place in the Universe. Large sharks generally cruise at a leisurely 1.5 miles (2.4 kilometres) per hour. Because most species fare poorly in captivity, the maximum swimming speed of a shark has seldom been measured. The Blue Shark (Prionace glauca) is an open ocean glider, planing on wing-like pectoral fins and flattened belly. There exists a dubious record of a small Blue Shark about 2 feet (0.6 metres) in length which was found to swim steadily against a current at 17.7 miles (28.5 kilometres) per hour and was reported to achieve 43 miles (69 kilometres) per hour in short bursts. The most reliable record of a Blue Shark at speed is 24.5 miles (39.4 kilometres) per hour for a 6.5-foot- (2-metre-) long individual.

The Shortfin Mako (Isurus oxyrinchus) is probably the champion speedster among sharks. It is an open ocean sprinter, with a highly streamlined body, a lunate tail supported by keels, a sharply pointed snout, large eyes and some of the wickedest-looking teeth in sharkdom. Like the White Shark (Carcharodon carcharias) and a few of its lamnoid relatives, the Shortfin Mako has a jury-rigged circulatory system which enables this species to retain metabolic body heat, making it functionally warm-bodied. It is also a spectacular and much sought-after gamefish, often leaping repeatedly when hooked. Among sport anglers, this explosive activity combined with dazzling ultramarine flanks has earned the Shortfin Mako the dramatic honorific, "Blue Dynamite". Famed western author and big game angler Zane Grey held this species in particularly high regard, noting that hooked Shortfins typically leap in sets of three, with the third leap usually the highest - sometimes as much as 15 to 20 feet (5 to 6 metres) above the surface. Calculations show that for a mako to leap 20 feet (6 metres) into the air, a speed of 24.6 miles (39.6 kilometres) per hour is required - and this for a shark impeded by the drag of a fishing line trailing from its mouth.

Underwater and unimpeded by a fishing line, the Shortfin Mako has been reliably clocked at 31 miles (50 kilometres) per hour, and there is a claim that one individual of this species achieved a burst speed of 46 miles (74 kilometres) per hour. But it is extremely difficult to get a fish in the wild to swim in a straight line over a measured course. Laboratory measurements of numerous kinds of fishes - representing a wide range of body sizes - swimming against an artificial current have revealed a surprisingly uniform maximum burst speed of about 10 times the body length per second. Thus, for an average-sized, 6.5-foot (2-metre) Shortfin, its theoretical maximum speed might be something on the order of 45 miles (72 kilometres) per hour. Yet some estimates of the top-speed of a Shortfin Mako are considerably higher.

In an effort to determine the maximum swimming speed of the Shortfin Mako, two New Zealand researchers undertook a simple experiment which yielded astonishing results. Off the coast of Auckland, aquarist Craig Thorburn and film-maker Mike Bhana videotaped a 3-foot (1-metre) juvenile Shortfin Mako - estimated to be about one year of age - chasing a baited camera trolled behind their boat. The shark seemed to have no trouble keeping up with the towed array at medium speeds, so the researchers decided to accelerate to see just how fast the little Mako could go. From this experiment, Thorburne and Bhana estimate that the shark accelerated from a dead stop to cover a distance to the bait of more than 100 feet (30 metres) in just two seconds.

If, as Thorburn and Bhana attest, the shark did indeed start from a standstill - which seems behaviorally unlikely - to cover the stated distance in the stated time, the little Mako must have achieved an acceleration of at least 50 feet (15 metres) per second, per second. This acceleration rate rivals that of the very fastest sport cars and seems rather improbable. Nevertheless, using this figure as the constant rate of acceleration, calculations suggest that by the time this little Mako reached caught up with the bait, it reached a top speed of about 68 miles (110 kilometres) per hour! But it should be stressed that if any of Thorburn and Bhana's estimates (the shark's initial speed, the actual distance covered, the time required to reach the bait, etc.) is inaccurate, this startling figure could be 'off' by quite a bit.

Not surprisingly, Shortfin Makos are able to catch even the fastest of fishes - there is a record of a 750-pound (340-kilogram) Mako with a whole 120-pound (54.5-kilogram) Broadbill Swordfish (Xiphias gladius) in its stomach; however, it is uncertain whether the shark out-sprinted or out-maneuvered the swordfish. The White Shark is one of the sea's paramount predators, able to catch and consume such speedy prey as tunas, sea lions, and dolphins. It is therefore natural to wonder about its top speed.

Unfortunately, no one has yet measured the swimming speed of a White Shark going flat-out. Analysis of White Sharks attacking a video camera-equipped surfboard off the South Farallon Islands, California, give some indication of this animal's attack speed. Current consensus among shark scientists is that the top swimming speed of the Great White is at least 25 miles (40 kilometres) per hour. My own rough, back-of-the-envelope-type calculations - using several methods - suggest that the White Shark may achieve burst speeds of 35 miles (56 kilometres) per hour or more. That may not seem very speedy, but it's seven times faster than the finest Olympic swimmer and probably at least ten times faster than you or I could manage.

4:33 AM - 7/18/2006 - comments {0} - post comment

Maui Lifeguards Save Shark's Life

It oIs nice to hear about this sort of news:

5:42 AM - 6/21/2006 - comments {0} - post comment

Campbellton shark fossil attracts New York scientist

An American scientist is hoping to use medical technology to better understand the inner workings of a prehistoric shark found near Campbellton.

The 400-million-year old shark is the oldest known intact shark fossil in the world.

Detail of shark fossil. (file)

John Maisey, a paleontologist with the American Museum of Natural History in New York, has travelled around the world to look at old sharks and says the Campbelton fossils are unique. "They are, in fact, some of the oldest known skeletons of early sharks, which makes them really important for us to study."

The Campbelton specimen is the size of a small, modern shark. It is a rare find, because it includes skin, cartilage and bone. Because sharks are mostly cartilage, they don't usually fossilize well.

The scientific journal Nature published a paper about the fossil in 2003. It was discovered in 1997 by New Brunswick geologist Randy Miller.

• FROM OCT. 6, 2003: Ancient shark provides clues to Darwin's mystery

Maisey says modern medical equipment will allow him to learn more about how sharks have evolved. He plans to use a CT scan – a series of X-rays taken at slightly different angles and then combined using a computer – to create a cross-sectional image of the fossil.

"Obviously we can't chop it up or section it mechanically, but CT scanning allows us to look inside the fossil to see its anatomy in greater detail."

The shark has been encased in rock for 400 million years. It is almost flat and Maisey says a CT scan will allow him to construct a three-dimensional picture. "You can then reconstruct the thing and digitally manipulate the images. You can restore it to its original, or as close to as possible, shape."

Maisey says he'll travel to Saint John this summer to study the shark, and make a trip to Campbelton to examine the site where it was found.

7:15 AM - 4/20/2006 - comments {0} - post comment

2005: better in Shark Attacks

Assertive and even aggressive human behavior could explain why shark attacks worldwide dipped last year, continuing a five-year downward trend in close encounters with the oceanic predators, new University of Florida research suggests...

Greater safety precautions and in-your-face responses to confrontations with sharks went a long way in reducing the total number of attacks from 65 in 2004 to 58 in 2005 and fatalities from seven to four, said George Burgess, director of the International Shark Attack File housed at UF’s Florida Museum of Natural History.

In contrast, there were 78 shark attacks — 11 of them fatal — in 2000, the all-time high record year for attacks since statistics were kept, he said.

There also were simply fewer sharks to attack people, a result of a decline in populations caused by overfishing of the carnivorous creature, which generally is slow to reproduce, Burgess said.

“It appears that humans are doing a better job of avoiding being bitten, and on the rare occasion where they actually meet up with a shark, are doing the right thing to save their lives,” he said.

In one such case, a surfer bitten by a great white shark off the Oregon coast on Dec. 24 had the presence of mind to drive it away with a well-timed punch to the nose, he said.

“That gentleman did precisely what he should do under those circumstances,” Burgess said. “A person who is under attack should act aggressively toward the shark and not follow the advice given to women who are having their purses snatched in New York City, which is to lie on the ground, play dead and give up the purse.”

Despite the worldwide decline, the number of attacks in the United States rose slightly, from 30 in 2004 to 38 in 2005. But that is still considerably lower than the recorded high of 52 in 2000, he said.

The same pattern emerged in Florida, the U.S. shark attack capital, where the number of attacks increased from 12 to 18 but was still well below the 2000 record of 37, he said.

The 2004 numbers were the lowest in more than a decade, however, and were probably due to Florida’s unusually active hurricane season, which kept people out of the water, he said.

In addition to last year’s 38 U.S. attacks, Burgess tracked 10 in Australia, four in South Africa and one each in the Bahamas, St. Martin, Mexico, Fiji, Vanuatu and South Korea.

Compared with previous years, the number of attacks in Australia was relatively high last year and in 2004, when there were 12, prompting some people to call for the installation of nets to barricade sharks from beaches, Burgess said. But the per capita rate of shark attacks has not risen over the past century, with apparent increases coinciding with a rise in population and Australia’s growing attraction to tourists in recent decades, he said.

The number of shark attacks at any particular time depends on a variety of factors, including oceanographic and meteorological conditions, abundance of prey items, and very important, the amount of time people spend in the water, he said.

“We need to remember there have been huge changes in how humans use the water over the last 20 to 30 years,” Burgess said. “When our parents and grandparents went into the water, they maybe wiggled their toes, or if they were very daring, jumped in and swam. People of our generation are surfing, diving, sail boarding, scuba diving, skin diving and engaging in all kinds of activities.”

Of this year’s four fatalities, two were in Australia, one in the Indo-Pacific island of Vanuatu and one in the United States. The U.S. attack occurred June 25 along Florida’s Gulf Coast, when 14-year-old Jamie Daigle was attacked by a bull shark while swimming off Sandestin. It was the state’s first death from a shark attack in four years.

Two days later, also in the Florida Panhandle, 16-year-old Craig Hutto lost his right leg to a shark while fishing in waist-deep water off Cape San Blas.

Five of the state’s 18 shark attacks last year occurred along Florida’s Gulf Coast, which is a greater proportion to the Atlantic coast than previous years, Burgess said. “It’s unusual to have only 13 attacks on the state’s eastern coast,” he said.

Elsewhere in the United States, five attacks occurred in South Carolina, four each in Texas and Hawaii, three in California, two in North Carolina and one each in New Jersey and Oregon.

Surfers were the most frequent victims, accounting for 29 incidents, followed by swimmers and waders, 20, and divers, four.

Source: University of Florida

4:41 AM - 2/16/2006 - comments {0} - post comment

The epic odyssey of a Great White Shark

Source: http://www.projectaware.org/uk/english/pts.asp

4:37 AM - 2/16/2006 - comments {1} - post comment

Learning about Sharks - funnky !

Tips to survive an attack:

Of course, the easiest way to avoid a shark attack: DO NOT GO INTO THE WATER. At a time when shark attacks have been dominating the media, you might want to take a moment to ponder whether or not you should be swimming at all. But, you should definitely avoided swimming in the dark. It makes it much harder for you to see the sharks, but doesn't make you taste any worse to them. Also, during the twilight hours is when most sharks tend to do their most severe amount of partying. If you go into the water early in the morning, the shark is likely to be hung over, and even if he couldn't stomach any food, he will eat you just on principle.

If you are alone, DO NOT GO INTO THE WATER. Always go into the water as part of a group, preferably an entire family, as sharks are ten times more likely to attack children. This makes it much easier to bargain with them, as sharks tend to be very reasonable if you will give them the opportunity to eat a small child.

If you resemble a sea lion, walrus or penguin, DO NOT GO INTO THE WATER. Particularly if you have been marinating in drawn butter for the better part of an hour. The odds are pretty good that a shark will not even think twice about eating you.

If you are already profusely bleeding when you arrive at the beach DO NOT GO INTO THE WATER. You'll make the sharks job much easier, thus making them very angry, as they like to be challenged.

If you are wearing shiny jewlery, DO NOT GO INTO THE WATER. Not so much beacuse the sharks will eat you, but because they will think that you are very tacky, and would go on E! with Joan Rivers and talk about your horrible fashion sense.

6:35 AM - 2/13/2006 - comments {0} - post comment

Video of Octopus EATING shark !

Amazing Video in Google Videos

Octopus EATING a shark

2:52 AM - 1/25/2006 - comments {3} - post comment

It's behind you: How to best fight off a shark

MIAMI, Florida (17 Jan 2006) --  An Australian diver has narrowly survived a shark attack by fighting it with his speargun - the latest in a long line of shark-related incidents. So what is the best way to take on a shark and win?

Bernie Williams, a 46-year-old Australian scuba-diver, fought off repeated attacks by an 11ft (3.5m) shark by hitting it on the nose with his speargun.

As is most often the case, he didn't see the shark coming until it bit him.

Mr Williams said: "It just came out from my left hand side... chomped on my arm and took me for a ride for about two metres.

"I stabbed it on the nose with a speargun, but it was just like hitting a lump of steel. It didn't slow down in the slightest."

The shark retreated before making another attack on Mr Williams, giving him just enough time to hide in a crevice near the ocean floor until his diving buddies came to the rescue.

So was Mr Williams' response a text book example of defence or are there better ways to take on Jaws?

Escape strategy

George Burgess, director of the Florida Program for Shark Research and the International Shark Attack File, says the first thing to do is get out of the water as soon as possible.

"Have an escape strategy at all times," he says, "But, if you're diving and can't get out of the water easily, find a place at the bottom of the ocean. This reduces the number of angles the shark can attack you from."

Mr Burgess recommends you swim back to back with your dive partner which gives you two pairs of eyes to watch for the shark.

Although getting out of the water as soon as you see a shark sounds like, sound advice, most attacks come out of the blue. Victims do not know they are in danger until the shark attacks.

"If you can't escape before an attack, hit it with an object - like a spear or camera or whatever you have to hand - avoid using your bare hands. You can replace your camera easily, but not your hands and feet.

"If the shark is persistent hit it hard on the end of the nose which is just a little north of the mouth. But be careful, if you miss you'll place your hand or weapon in the shark's jaws."

In an all-out shark-fight Mr Burgess, perhaps unsurprisingly, recommends being as aggressive as possible.

Play dead?

"Fight like a man," he says, "If you can, get your hands into the gill openings on the side of the shark which are very sensitive."

He also debunks the myth that remaining motionless may fool a circling shark into ignoring you and heading off for other prey.

Whatever you do, don't ever play dead, if you're attacked and you can't escape you will have to fight back and then get out of the water as soon as you can."

Aidan Martin, Director of Australia's Reefquest Centre for Shark Research, echoes Mr Burgess' advice but adds that it's important not to panic.

"That may seem like a tall order under the circumstances, but most shark attacks result in injuries that are readily survivable. Do nothing to unnecessarily incite a retaliatory strike... I have no doubt it's possible to annoy a shark."

Mr Martin adds you should try to staunch any bleeding, even before you get out of the water.

So, full marks to attack-survivor Mr Williams who responded exactly as recommended. But should we all be more aware of the dangers? Are sharks attacking more humans?

Responsibility

Decade on decade the number of shark attacks on people has increased.

However, Mr Burgess says, this is only because the number of humans spending more time in the water, and in deeper waters too. In effect, people are invading the sharks' territory.

"When I starting diving years ago we were oddballs, now it is a very common water activity. In reality, we're pushing the sharks out of the water."

Mr Martin agrees: "We need to stop treating the ocean like a swimming pool. It is a wilderness. And when we enter this liquid wilderness, we must assume responsibility for our own safety."

News by BBC

6:53 AM - 1/20/2006 - comments {1} - post comment

Why Sharks?

My first Blog

Taken from Bite-Back Website

Right now shark, marlin, swordfish, monkfish and orange roughy are being threatened with extinction. Consumer demand for these species has outstripped supply and now these increasingly rare fish are being killed faster than they can reproduce

However, there is only one reason why this catastrophic situation remains uncurbed … because people continue to buy these fish.

When we stop buying these fish, they'll stop killing them.

Without change, we are either participants or witnesses to an underwater genocide fuelled purely by greed, ignorance and ambivalence.

In fact not since the height of the ivory trade in the early 1980s, when 200 elephants were being killed each day, has the planet known of a killing spree so senseless and unnecessary.

6:36 AM - 1/12/2006 - comments {0} - post comment