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Great Lakes Advocates Hope Electric Fence Keeps Asian Carp Out of Canadian Waters

Posted on: Sunday, 22 July 2007, 15:10 CDT

By MICHAEL OLIVEIRA

(CP) - Hauling in a 50-kilogram fish might sound like fishing enthusiast's dream come true, but for the protectors of the Great Lakes, it's an alarming doomsday scenario that's dangerously close to becoming reality.

Scientists already have their hands full dealing with a host of destructive invasive species in the Great Lakes - sea lampreys, zebra mussels, round goby and rusty crayfish.

But they're also keeping a wary eye on the south and what could be a potentially bleak future for the creatures of the Great Lakes.

An electric barrier is all that's keeping invasive Asian carp from entering the Great Lakes basin, where it could wreak havoc with the ecosystem and wipe out the vast diversity of creatures the lakes are known for.

The monstrous fish can grow over a metre in length and dozens of kilograms in weight, and once they establish a new home, other fish are no match. The Illinois River has become so overrun, nine out of every 10 fish being surveyed in the water are now Asian carp.

An invisible line of electric current keeps the carp from entering the lakes at the Chicago Sanitary and Ship Canal. Fish get close to the electric barrier but turn around and swim away rather than trying to cross it.

Becky Cudmore of Fisheries and Oceans Canada travelled to the U.S. to study the carp in the river and was awed by what she saw.

When the fish are startled by passing boats, they often leap two or three metres out of the river and slam back into the water with a loud thud.

"All the video in the world does not prepare you for the shock of these species flying through the air," said Cudmore, who is a manager of the National Centre of Expertise for Aquatic Risk Assessment.

"It was a shock to see this occurring and just very sobering to know the Great Lakes that we work really hard to protect are faced with this threat. To think that could happen here is horrifying."

The fish commonly jump into boats and crash into people, and have caused black eyes, concussions and broken bones.

"One hit me in the shin and my leg was numb for several hours after it," Cudmore said.

It's very likely Asian carp could gain the same foothold throughout the Great Lakes if they are able to get established in just one of the lakes, said Francine MacDonald of the Ontario Federation of Anglers and Hunters.

There have been a few isolated reports of Asian carp spotted in Ontario waters, but in all cases the fish were removed before any damage could be done.

In 2004, the Ontario government banned the sale of live Asian carp - they were popular at fish markets and for use in aquariums and backyard ponds - out of fear they could eventually end up in lakes or streams.

Now officials can only hope the electric fence guarding the Great Lakes will continue to work and keep the predators at bay, MacDonald said.

"We do not want to see these invaders introduced to the Great Lakes. They could have major impacts and probably would have major impacts."

Source: Canadian Press

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