While looking for scientific articles about sharks on-line I discovered scientific research concerning Great White Sharks. To be more specific,this research has to do with Great White sharks which live off the waters of California USA.
Researchers have long thought that white sharks migrated across oceans, but a new study in the Proceedings of the Royal Society B shows that the population in the northeastern Pacific Ocean, along California, hasn't mixed with other white sharks for tens of thousands of years!!
"White sharks are a large, highly mobile species," said Salvador Jorgensen, a postdoctoral scholar at Stanford's Hopkins Marine Station. "They can go just about anywhere they want in the ocean, so it's really surprising that their migratory behaviors lead to the formation of isolated populations."
At the newsmongobay.com website I found an article written by Jeremy Hance, entitled, "California's great white sharks are a distinct population", which was published on November 4,2009.
In the article Mr.Nance states:
"Employing satellite tapping, passive acoustic monitoring, and genetic tags, researchers with the Tagging of Pacific Predators (TOPP) found that the white shark (Carcharodon carcharias) in northeastern Pacific frequently return to the same spot over and over, and sometimes remain in one hunting ground for over a hundred days."
"The sharks were detected frequently at their chosen site," Jorgensen said, "which means that they are patrolling around there nearly constantly, for long periods of time. They will occasionally visit one of the adjacent sites, but they always come back."
"They also never stray far. Genetic studies show that the population of northeastern Pacific white sharks was likely founded by a small number of sharks sometime in the last 200,000 years and hasn't mixed with other shark populations near Australia and South Africa since."
This is amazing to me,seeing as you would think that great whites would be migrating to different ocean regions based upon the availability of food sources.
"If you had asked us a few years ago, we would have said white sharks found in California probably migrated throughout the Pacific. Now, even though we know they travel great distances, their paths are surprisingly constrained to specific routes. This explains how a highly migratory marine species becomes a genetically isolated population. This also makes it much easier to appreciate how vulnerable the northeastern Pacific white shark population could become if too many individuals were taken as either catch or bycatch, since these sharks do not appear to interbreed with other shark populations," said Molecular geneticist Carol Reeb, a research associate at Stanford."
To read the entire article please click on the following link:
http://news.mongabay.com/2009/1103-hance_greatwhite.html
Hopefully this new research will help scientists better understand Great white sharks so that this understanding will enhance our ability to learn what human behaviors must be changed to ensure the survival of Great white sharks in the oceans of our planet! I wonder why these Great White sharks have not chosen to move elsewhere during their daily lives?
New research also shows that humans have underrated the cognitive abilities of sharks:
Many sharks have good learning capacity, which is one way we measure intelligence," says Samuel Gruber, a marine biologist at the University of Miami's Rosenstiel School of Marine and Atmospheric Science (RSMAS), who discovered in 1975 that lemon sharks could learn a classical conditioning task 80 times faster than a cat or rabbit. "I was shocked to find that they could learn so rapidly," he says. "
I found that quote in a new article about sharks posted at the Scientific America Website, the article is entitled, " Today's Sharks: Smart, Tagged, and in Short Supply" and was written by
John Pavlus. A direct link to this article is: http://www.scientificamerican.com/article.cfm?id=sharks-tagged
Source of image:http://theworldisshaking.blogspot.com/2010/10/unprecedented-great-white-shark.html
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