This great white shark is the subject of a criminal investigation in California. Credit: Ashley Kern
When one of the ocean’s top predators washed up dead on a beach, it is likely that there is something wrong must have happened. On Sunday (17 June), beach goers found a young male great white shark (Carcharodon carcharias), with a weight of 500 pounds (225 kilograms), and reach 8 feet (2.4 metres) long on Beer Can Beach in Aptos, California, near Santa Cruz, reported KION.
But the authorities are not disclosing the shark is the cause of the death, and is now the subject of a criminal investigation by the California Department of Fish and Wildlife (CDFW).
KION reported the male shark appeared healthy in addition to a few relatively small cuts, possibly caused by sea lions. But it is unclear whether that scratching caused the creature’s death, KION reported.
Researchers from CDFW collected the shark on Sunday afternoon and performed a necropsy at the Long Marine Lab in Santa Cruz on Tuesday (19 June), but they are not revealing what they have found. “Upon receipt of the lab, necropsy results, the CDFW’s Law Enforcement Division is now taking the research,” a representative of CDFW told Science in an e-mail. The representative refused to comment further. [See Photos of the Great White Shark on Beer Can Beach]
It is not a frequent for great white sharks to wash ashore, although one washed ashore in the same area last year. “The white shark population is, in essence, booming off the coast of California,” said David Ebert, a shark scientist and the director of the Pacific Shark Research Center at Moss Landing Marine Laboratory in Moss Landing, California. “Would it not seem strange that occasionally they would wash,” he said.
Great white sharks are classified as vulnerable by the International Union for Conservation of Nature. But great white shark populations are making a comeback since 1972, when the Marine Mammal Protection Act was passed, said George Burgess, a marine biologist and director emeritus of the Florida Program for Shark Research at the University of Florida. The law made it illegal to the injury of all marine mammals, including seals and sea lions, that makes the great white shark is the main source of food. And, because they are classified as fragile, large, white is illegal to catch without a special permit.
What could kill such a beast?
Great white sharks don’t usually have predators, except for occasional attacks by killer whales (Orcinus orca), Burgess said. “The orcas have a tendency to go for the belly and eviscerate the white shark,” Burgess told Live Science. But the belly of this great white shark was still intact, and there were no cracks visible in photos. [Photos: orcas Are Chowing Down on the Great-White-Shark Bodies]
The great white that washed up dead in the same area of last year had a bacterial infection of the brain that also affect salmon sharks (Lamna ditropis) and the thresher sharks (Alopias species), Ebert said. It is unclear how the sharks become infected with the brain bacteria, but it is a major cause of death in salmon sharks along the California and Oregon coasts, scientists reported in a 2012 study in the journal Veterinary Pathology.
People are able to kill a great white shark, but that is rare, Ebert said. “They are not taken, often in the fisheries,” he said. “It is a good size animal, so it is not the kind of thing that someone probably trying to catch.” There is a fee for accidentally catching a great white shark, who becomes entangled in a fishing net, he said, but it is prohibited to target them.
Some anglers might be tempted to catch a great white shark, though, because the shark fins are a delicacy in the Chinese culture, and elsewhere. “That fins are worth a great deal of money and, if they were sold on the black market, they would have made a very pretty penny,” Burgess said. This shark still had all of his fins, so Burgess wonders if it is caught accidentally in a fishing net and then back in the water by someone who didn’t know what else to do.
Ebert said that he was “not aware of any other instances in California where a white shark washing up has led to a criminal investigation.”
None of the experienced shark researchers has any idea why the CDFW’s Law Enforcement Division is investigating the shark’s death. But, Burgess said, “If this was a result of human interaction, it had to be prohibited.”
Original article on Live Science.