The great white shark's ominous reputation may be overblown, a San Francisco researcher says. "It's apparent that their speed, grace and maneuverability have been greatly exaggerated," says John McCosker, director of the Steinhart Aquarium at the California Academy of Sciences. The sharks have killed at least seven swimmers and injured more than 55 in recent years along the Northern California coast and officials say a management plan may be necessary to control the increasing shark population. McCosker said he and other researchers in Australia were surprised to learn that the great white rarely swims faster than 3 miles an hour. A skilled human swimmer can move at close to 4 miles an hour, he said. But, McCosker warns, although slow and often awkward, the shark is a skilled hunter.