Sharp decline in shark numbers harming ecosystems, scientist says

Sharks may strike fear in to the hearts of those who like to bathe in oceans around the world, but their numbers are drastically declining, which is harming the ecology of marine environments, according to a University of Windsor scientist.

“In terms of ecology and integrity of our food webs, these animals obviously have a role to play,” said Nigel Hussey, a post-doctoral fellow in the university’s Great Lakes Institute for Environmental Research. “When we look at these predators they may look like scary animals with big teeth, but at the end of the day they are playing an important role in maintaining the health of the ecosystem.”

With a booming economy in Asia, where shark fin soup is considered a delicacy, overfishing of sharks is a real problem and can cause unwanted population expansions of other species they feed on, Hussey said.

“The scale of decline can be very regionalized,” he said. “For example in the in the northwest Atlantic, a few years ago a study reported that many of the large shark species such as scalloped hammerhead, great whites, tiger sharks, the sharks that we’re all familiar with had declined by about 90 per cent in the last 20 to 30 years.”

Along with members of The Cousteau Society, Dr. Hussey is conducting research in the Red Sea off the coast of Sudan, developing a regional shark and ray conservation management program that he hopes will ultimately lead to world heritage site status for the region. That status, he said, would give the United Nations the clout it would need to better enforce international regulations to prevent overfishing of sharks there.

In 2007, Hussey participated in a coastal zone management survey to get baseline data on the marine habitat off Sudan and the species that live in it. He said they surveyed 16 reefs along the coast and every one had large schools of hammerheads in them.

“We realized very quickly that it was a unique biodiversity hotspot for sharks, especially for large predators,” he said. “They have very healthy shark populations there.”

Hussey will travel back to Sudan and will begin tagging sharks with satellite devices to help track their migratory patterns. The data collected from those tags will be included in the conservation plan, he said.

Hussey will appear today on CJAM 99.1 FM on Research Matters, a weekly talk show that highlights the work of University of Windsor researchers and airs every Thursday at 4:30 p.m.


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