its a dolphin
http://www.snopes.com/photos/surfer.asp
Origins: The photograph displayed above is indeed real, but it doesn't depict the hair-raising scene most viewers think it does.
This picture was taken by photographer Kurt Jones on 9 April 2003 at Surfrider Beach in Malibu, one of California's premier surfing beaches. But as the version of the photograph posted on the web indicates, however, the ominous-looking finned creature lurking just beneath the surface of the waves is a dolphin (possibly a bottlenose), not a shark.
A subsequent photograph of the animal taken later in the day demonstrates conclusively that it was in fact a dolphin:
http://www.surfshooter.com/DolphinInfo.html
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