The scalloped hammerhead shark, which has declined by 99 per cent over the past 30 years in some parts of the world, is particularly vulnerable and will be declared globally endangered on the World Conservation Union (IUCN) list.
“Sharks are definitely at the top of the list for marine fish, that could go extinct in our lifetime,” said Julia Baum of the Scripps Institution of Oceanography in California and a member of IUCN shark specialist group.
“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,” she said.
Baum said that in addition to the scalloped hammerhead, other shark species that will be added to the revised IUCN endangered list later this year are the smooth hammerhead, shortfin mako, common thresher, big-eye thresher, silky, tiger, bull and dusky.
“The perception has been that really wide-ranging species can’t become endangered because if they are threatened in one area, surely they’ll be fine in another area,” said Baum. “But fisheries now cover all corners of the earth and they’re intense enough that these species are being threatened everywhere.”
Recent studies have shown that all shark populations in the north-west Atlantic Ocean have declined by an average of 50 per cent since the early 1970s.
Market for fins
Shark numbers can become depleted very quickly because they take a long time to mature — 16 years in the case of a scalloped hammerhead. Until recently the eating of shark fin was a delicacy restricted to the rich in China, said Baum, but as the country’s middle class has grown in the past 25 years, so has the market for shark fins.
Excessive fishing has caused a 90 per cent decline in shark populations across the world’s oceans and up to 99 per cent along the US east coast, says Baum.