Search This Blog

Friday, November 6, 2009

Great Whites hang out in Pacific's 'shark cafe'


Photo by Terry Goss, copyright 2006. Taken at Isla Guadalupe, Mexico, August 2006

Some fascinating new research has been announced concerning the behavior of Great White Sharks.Scientists at one time thought Great White sharks were loners exclusively.However, new research indicates this theory is incorrect. According to an article posted online:

"Great Whites may be loners, but the ocean's most feared predators also hang out together between Mexico and Hawaii at a deep sea watering hole known as the "White Shark Cafe," a study reveals.
No animals inspire more fascination and frissons, but scientists admit to knowing precious little about how the endangered Great Whites get around and get it on as they navigate the globe's oceans."

"Like other open water sharks prized for their meat -- and, in Asia, especially for their fins -- the magnificent hunting machines are threatened with extinction, according to experts.

"The new study identifies a distinct population and a major new genetic grouping of the Great White in the eastern Pacific, only the third such "clade" ever found.
The other two concentrations of Carcharodon carcharias are off the coast of South Africa, and in the waters between Australia and New Zealand."

"It had long been assumed shark species at the top of the ocean food chain that roam the high seas looking for food and mates did so almost randomly.
But using satellite tagging, acoustic monitoring of shark "hot spots" and genetic samples, a research team led by Barbara Block of Stanford University found -- to their surprise -- that the eastern Pacific's Great Whites are real homebodies.
Over an eight year period, nearly 100 sharks were electronically tagged, and even more had tissue samples taken by scientists working from a ship."

"Not only do the sharks consistently migrate along the same paths, they stick to a schedule too.
Between August and December, the Great Whites -- which can grow up to six metres (20 feet) and three tonnes -- stalk waters off the coast of central and northern California, feasting on seals and sea lions.
Their preferred hunting grounds in this area are known as the "red triangle", notes the study, published in the British journal Proceedings of the Royal Society B."
"Starting in January, they head for the deep blue around Hawaii some 4,000 kilometers (2,500 miles) to the west, where they are found in largest numbers between April and July."
"But some -- especially males -- loiter at a halfway point known as the "White Shark Cafe", with females coming and going for what scientists presume is a bit of shark intimacy."

"The new findings will help conservation efforts, the study concludes: "The population's fidelity to predictable locations offer clear population assessment, monitoring and management options."
A third of the world's open water sharks -- including the Great White and hammerhead -- face extinction, according to the largest ever shark survey, completed earlier this year by the International Union for the Conservation of Nature (IUCN)."
"For decades, significant numbers of sharks -- including blue and mako -- have perished as "by-catch" in commercial tuna and swordfish operations.
More recently, the soaring value of shark meat has prompted some of these fisheries to target sharks as a lucrative sideline."
"Europe is the fastest growing market for meat from the porbeagle and another species, the spiny dogfish.
Around 100 million sharks are caught in commercial and sports fishing every year, and several species have declined by more than 80 percent in the past decade alone, according the International Fund for Animal Welfare (IFAW)."

"Satellite tracking systems and acoustic sensors are giving researchers insights into the behavior and lifestyles of some very elusive animals in the ocean, including the fabled white shark."

"Researchers from several institutions, including Stanford University, have joined their efforts in a Census of Marine Life project called Tagging of Pacific Predators (TOPP). Since the project began in 1999, they have attached more than 3,000 tags to sharks, seals, whales, tunas, squids, turtles, albatross and more. For the first time, these TOPP researchers are getting a glimpse of a pelagic ecosystem from the California Current to the North Pacific at daily, seasonal and yearly time scales."
"Along with the white shark, the TOPP researchers also have been studying the routes and habits of two cousins of the white shark: the salmon shark, whose range extends from the glaciers of Alaska down to Baja California, where it crosses over the white sharks' territory along the continental coast, and the mako shark, which resides along the continental shelf off California. The team also has tagged thresher sharks and blue sharks."
"Sharks are a vital part of oceanic ecosystems. As the top predators in the food chain, they regulate the populations of the species below them. If shark populations get in trouble, it can trigger a cascading effect all the way down the food chain. The TOPP team has used several distinct tag technologies to get a simultaneous view of how these sharks divide up the ocean turf."
"Salvador Jorgensen, a postdoctoral researcher at Stanford University's Hopkins Marine Station and the Monterey Bay Aquarium, is part of the group that has been tagging and monitoring white sharks, more popularly known as great white sharks."
"Jorgensen discussed the team's work Sunday, Feb. 17, at the American Association for the Advancement of Science (AAAS) annual meeting in Boston."
"What they have found has opened up a whole new vista in the white shark's world. It turns out white sharks are quite the sightseers.
"Jorgensen and his colleagues have tagged more than 100 white sharks along the central California coast. Home to numerous seal and sea lion rookeries, the area along the continental shelf is practically one long lunch counter for the white sharks. But in spite of the fine dining available there, the sharks exhibit an urge to roam."
"Through tracking the tagged sharks, the TOPP team has found two distant destinations that the sharks favor, both of which they visit on a regular, annual travel timetable. Each winter the white sharks head out from the California coast, with some going to the Hawaiian Islands. Most, however, head to another hotspot, out in the middle of the Pacific Ocean. This second location is roughly 1,300 miles from the mainland—about half the distance to Hawaii—and a few hundred miles to the south of the direct route to the islands. Dubbed "the white shark café" by the researchers, just what the attraction is out there remains something of a puzzle. But what is clear is that all the sharks that summer along the California coast show remarkable fidelity; when they return to the mainland, they head for the same local neighborhoods that they favor every summer."
"These animals appear again and again at very specific areas," Jorgensen said. Despite the sharks' ability to move through the ocean to wherever they please, they stick to consistent routes and destinations. It is a striking finding, because white sharks are found off South Africa and Australia, in addition to the West Coast of North America, but what the TOPP team and other researchers have found is that the populations do not appear to mix. New data presented by the TOPP team indicate that even between Pacific Ocean basin populations there are genetic differences. This means that white sharks, at least the females, have maintained long term isolation in the Eastern Pacific."
"This is really important in terms of management, so that management can focus on these population units," Jorgensen said. "And this really sets the stage for us to census the population, now that we know it is a confined population in the eastern Pacific."
There is another group of white sharks that tend to congregate near Guadalupe Island, offshore from Baja California, south of the California population that the TOPP team has been studying, but it is not yet clear whether they are distinct from the central California group.
Most of the tags used by the TOPP researchers have been electronic tags that are monitored by satellite. Those tags provide location data when the sharks are on the high seas. The other tags are acoustic tags; sensors installed along the California coast pick up the signal whenever one of the tagged sharks swims by.
"The TOPP program maintains a live access server that gives regular updates on the locations of the sharks that have been tagged. "My favorite activity is to wake up and check where the sharks are," said Barbara Block, the Charles and Elizabeth Prothro Professor in Marine Sciences at Hopkins Marine Station."
"Block is one of the researchers on the TOPP team and Jorgensen is doing postdoctoral research in Block's lab. TOPP partners in the shark research consortium include scientists from the University of California-Davis, the National Oceanic and Atmospheric Administration, PRBO and the Pelagic Shark Research Foundation."

This graphic shows the route of a single tagged white shark as it swam from the Farallon Islands, off the central coast of California, to the mid-oceanic area known as the “White Shark Café” and then back. 

To see where the great white sharks have been and are today in the World's waterways check out this website: 

To watch a trailer of a film called "White Shark Cafe" please click on the following link:

Here is a link to a CBS news report concerning
"Great White Cafe":

No comments:

Visit GM Alexandra Kosteniuk's Women's Chess Blog:Please click on the image below:

Visit GM Alexandra Kosteniuk's Women's Chess Blog:Please click on the image below:
Chess needs more women and girl participants and administrators!

Thoughts worth thinking about

"Our subconscious minds have no sense of humor, play no jokes and cannot tell the difference between reality and an imagined thought or image. What we continually think about eventually will manifest in our lives."-Sidney Madwed

Laws alone can not secure freedom of expression; in order that every woman and man present their views without penalty, there must be spirit of tolerance in the entire population.- Albert Einstein Too often we underestimate the power of a touch, a smile, a kind word, a listening ear, an honest compliment, or the smallest act of caring, all of which have the potential to turn a life around. - Leo Buscaglia

A person's true wealth is the good he or she does in the world. - Mohammed

Our task must be to free ourselves... by widening our circle of compassion to embrace all living creatures and the whole of nature and its beauty. -Albert Einstein

The best way to find yourself, is to lose yourself in the service of others. - Ghandi

The unselfish effort to bring cheer to others will be the beginning of a happier life for ourselves. - Helen Keller

Aim for success, not perfection. Never give up your right to be wrong, because then you will lose the ability to learn new things and move forward with your life. Remember that fear always lurks behind perfectionism. Confronting your fears and allowing yourself the right to be human can, paradoxically, make yourself a happier and more productive person. - Dr. David M. Burns

Life is as dear to a mute creature as it is to man. Just as one wants happiness and fears pain, just as one wants to live and not die, so do other creatures. -His Holiness The Dalai Lama

Mankind's true moral test, its fundamental test (which lies deeply buried from view), consists of its attitude towards those who are at its mercy: animals. And in this respect mankind has suffered a fundamental debacle, a debacle so fundamental that all others stem from it. -

Milan Kundera, The Unbearable Lightness of Being

The worst sin towards our fellow creatures is not to hate them, but to be indifferent to them. That's the essence of inhumanity. -George Bernard Shaw

Ego's trick is to make us lose sight of our interdependence. That kind of ego-thought gives us a perfect justification to look out only for ourselves. But that is far from the truth. In reality we all depend on each other and we have to help each other. The husband has to help his wife, the wife has to help the husband, the mother has to help her children, and the children are supposed to help the parents too, whether they want to or not.-Gehlek Rinpoche Source: "The Best Buddhist Writing 2005 pg. 165

The hostile attitude of conquering nature ignores the basic interdependence of all things and events---that the world beyond the skin is actually an extension of our own bodies---and will end in destroying the very environment from which we emerge and upon which our whole life depends.