Surfersvillage Global Surf News, 28 June, 2009 : – – A third of the world’s open-water sharks — including the great white and hammerhead — face extinction, according to a conservation survey that singles out overfishing as the main culprit. The survey of 64 species of open-water sharks and rays by the International Union for the Conservation of Nature notes the demand for shark fins, considered a Chinese delicacy, has soared along with income levels in China in the past decade.
Flinders University shark ecologist Charlie Huveneers says the proportion of sharks endangered was higher for the open-water sharks than for sharks in general, mainly because they were large species with slow reproductive rates and were slow to mature. Some, such as the grey nurse, produced only two pups every two years.
“That’s one of the reasons why that species is listed as critically endangered in NSW,” he said. Open-water shark species also lived in areas that were heavily fished and hard to regulate. The report identified the great hammerhead and scalloped hammerhead sharkand the giant devil rays as endangered. The smooth hammerhead, great white, basking and oceanic white-tip sharks are listed as vulnerable as are two species of makos.
Dr Huveneers said fishermen targeted sharks for their fins. The rest of it was discarded. Shark meat can fetch $1-$5 a kilogram, but the fin could bring up to $200 a kilogram. Commercial swordfish and tuna fisherman also caught sharks such as the blue shark and mako shark accidentally. Sharks are important in the ecosystem, especially those at the top of the food chain such as the white, great white and great hammerhead.
Reducing their numbers could prompt an increase in the number of cownose rays, which consumed scallops. “The cascading effect of the decreasing of large sharks has an impact on the whole ecosystem, including humans who work in and benefit from the scallop industry,” he said.
Check out more Images of Sharks on the Red List