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Carp not welcome to live in Delta Marsh

Program aims to rid invasive fish from wetland

By: Bruce Owen

Posted: 02/2/2013 1:00 AM | Comments: 0

The province, Ducks Unlimited and its partners are trying to rid Delta Marsh of invasive, habitat-destroying carp while allowing other species to thrive. (JOE.BRYKSA / WINNIPEG FREE PRESS ARCHIVES) Photo Store

Carp Be Gone.

That's the short name for a $3.5-million program unveiled Friday by the province and Ducks Unlimited Canada to restore Delta Marsh on Lake Manitoba by stopping carp, a fat, ugly invasive fish, from getting into the marsh.

The common carp has the nasty habit of destroying habitat by rooting out sensitive marsh plants when it feeds and spawns.

The eight-year plan involves the installation of special screens installed at access points to the Lake Manitoba marsh, such as under bridges and at culverts, to keep carp out of the marsh during the spring and early summer, but allow other smaller fish such as pickerel and yellow perch to come and go without interfering with their spawning.

The plan's goals: By keeping the carp out, the marsh will rejuvenate itself for wildlife and waterfowl that have been driven out over the past 50 years. Plus, with plant life restored, the marsh will again act as a filter to help keep nutrients, such as algae-causing phosphorus, out of the lake.

"We've got to turn it around," Conservation and Water Stewardship Minister Gord Mackintosh said. "There's too much at stake."

The project is the largest of its kind in North America and will be administered by Ducks Unlimited. Its announcement coincides with World Wetlands Day today. The province's contribution is $575,000. Ducks Unlimited Canada and its partners, including Wildlife Habitat Canada, are contributing $3 million for a total project contribution of $3.5 million.

Prof. Gordon Goldsborough, associate professor of biological sciences at the University of Manitoba, said research over the past four years has found vegetation will recover on the 18,000-hectare marsh if carp are prevented from entering it during the late spring and summer. Carp do not overwinter there because it is too shallow.

"I'm willing to lay money we see improvement in the very first year," Goldsborough said. "I think in the long run we're going to have an understanding that will help save a lot more of the marshes of Manitoba, many which are at threat."

The screens will have metal bars spaced seven centimetres apart, allowing fish vital to commercial fishers to spawn in the marsh, but blocking the much bigger carp.

"We want bars wide enough apart that the majority of fish can pass between them," Goldsborough said.

Coupled with the carp exclusion project, the Manitoba Métis Federation and the Manitoba Habitat Heritage Corporation plan to have fishers catch the carp as they congregate by the fish screens. Their goal is to expand the market for carp roe.

"There's money to be made here for the fishermen," MMF minister of fisheries Joe Parenteau said. "It's a win-win for everyone. We can get rid of the carp that are causing the damage in the marsh."

bruce.owen@freepress.mb.ca

Carp factoids

The common carp, native to Asia and parts of Europe, was first introduced to Manitoba in 1886 to be a cheap food source and has spread throughout the Red and Assiniboine rivers and lakes Winnipeg and Manitoba.

By 1954 they were a nuisance to commercial fishers and had little value.

Carp are large bottom-dwelling fish that take on the taste of a river or marsh bottom.

It's recognized by its small eyes, thick lips with two barbels at each corner of the mouth, large scales, and strongly serrated spines on its fins. Colour varies, but is often brassy yellow, olive green or silvery grey on its back, fading to silvery yellow on the belly.

Carp disrupt wetlands by regularly ripping up vegetation when feeding and spawning and stirring up silt and sediment, which stops sunlight from reaching other aquatic life.

The largest Manitoba carp on record was caught in 1997 from the Red River. It was 108 cm (42.5") long.

The potential value of carp is its roe, a poor man's caviar. The average price per kilogram of common carp roe in Manitoba was $2.06 in 2011.

-- Source: Invasive Species Council of Manitoba

Republished from the Winnipeg Free Press print edition February 2, 2013 A16

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