Hammerhead added to list of sharks close to extinction

ONE of the world's most recognisable sharks has been added to the official endangered species list and could soon be heading towards extinction.

The scalloped hammerhead, so-called because of its unusual hammer-shaped snout, has starred in countless diving movies and marine documentaries.

But like other sharks it has fallen victim to fishing by-catch and the high value placed on its fins, which are considered a delicacy in China.

The shark, whose numbers have declined by 99 per cent in the past 30 years in some parts of the world, is among nine more sharks to be declared endangered on the World Conservation Union list.

"If we carry on the way that we are we're looking at a really high risk of extinction for some of these shark species within the next few decades," said Julia Baum, of the Scripps Institution of Oceanography in California and a member of the World Conservation Union's shark specialist group.

Other shark species that would be added to the endangered list later this year were the smooth hammerhead, shortfin mako, common thresher, big-eye thresher, silky, tiger, bull and dusky, she said. There are already 126 species of shark on the conservation union's list.

"The perception has been that really wide-ranging species cannot become endangered because if they are threatened in one area, surely they'll be fine in another area," Ms Baum told the American Association for the Advancement of Science annual meeting in Boston. "But fisheries now cover all corners of the Earth, and they're intense enough that these species are being threatened everywhere."

Shark numbers can become depleted very quickly because they take a long time to mature - 16 years in the case of a scalloped hammerhead. The decline in predators such as sharks can have devastating consequences for the local marine ecology.

Fishing for sharks in international waters is unrestricted, but Ms Baum supports a recent UN resolution calling for immediate limits on catching sharks and a ban on shark finning.

Some conservation efforts for sharks will focus on newly identified hotspots where sharks congregate during migrations. Peter Klimley of the University of California, Davis, found that scalloped hammerheads migrate along fixed "superhighways" in the oceans, speeding between a series of "stepping stone" sites near coastal islands ranging from Mexico to Ecuador.

"Hammerhead sharks are not evenly dispersed throughout the seas, but concentrated at seamounts and offshore islands," he said.

Guardian News & Media

Contributed by Tim Hochgrebe added 2008-02-19