Wisconsin Sea Grant Littoral Drift 02_95

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Above: With no significant predators, the ruffe threates to spread throughout the Great Lakes. Photo courtesy of Minnesota Sea Grant.

Table of Contents

1. Taking on the Ruffe

2. Using Zebra Mussels to Filter Milwaukee's Water

3. Aquatic Sciences Seminars Continue

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Taking on the Ruffe

The Eurasian ruffe may not get much respect, but it's sure getting a lot of attention.

First identified in North America in 1987 by the Wisconsin Department of Natural Resources in collections taken from Duluth-Superior Harbor, the small perch-like invader has reproduced prolifically and spread as far eastward as the Ontonagon River in Michigan, located 180 miles east of Duluth.

With no sport or commercial value, and no significant predators, the ruffe threatens to spread throughout the Great Lakes, disrupting ecosystems and driving out native fish species. Population studies conducted in the Duluth/Superior Harbor since 1989 indicate dramatic increases in the ruffe population and declines in native fish populations, including yellow perch, trout-perch, spottail shiner and emerald shiner.

In April 1992 the Federal Aquatic Nuisance Species (ANS) Task Force declared the ruffe an aquatic nuisance species as defined by the Nonindig- enous Aquatic Nuisance Prevention and Control Act of 1990; a Ruffe Control Committee subsequently met to develop a control program to halt the ruffe's spread from western Lake Superior.

While most people agree the ruffe threat warrants action, deciding on appropriate measures has been a challenge, said Tom Busiahn, project leader at the U.S. Fish and Wildlife Service Fishery Resources Office in Ashland, Wis., and chairman of the Ruffe Control Committee.

"Nobody is saying 'do nothing' anymore, but there's a diversity of opinion on what should be done," Busiahn said.

The ruffe committee's most contentious proposal treatment involves using chemical piscicides such as trifluoro-nitro-methylphenol (TFM) to stabilize or reduce the ruffe population at the periphery of its range. TFM is the toxicant currently used to control sea lampreys in the Great Lakes basin. National Biological Survey (NBS) tests showed TFM was toxic to ruffe but not lethal to native species like yellow perch or brown trout. However, NBS studies of treatments in Wisconsin's Middle and Amnicon rivers showed that current TFM doses for sea lampreys were only moderately successful in reducing ruffe populations.

In April 1994, the Council of Lake Committees, representing state, tribal and provincial fisheries management agencies on the Great Lakes, gave qualified support for experimental TFM treatments. TFM treatments designed specifically for ruffe will be part of the control program.

"We're planning to apply treatments in some rivers and estuaries in June," Busiahn said.

Though full implementation of the control program awaits final approval, a monitoring program in all the Great Lakes is underway to keep track of the ruffe's range expansion. U.S. and Canadian shipping interests have adopted a voluntary ballast-water management program to prevent spreading ruffe throughout the Great Lakes via "contaminated" ballast water discharge. And federal, state and provincial resource management agencies and the Minnesota and Michigan Sea Grant programs have also sponsored public education programs throughout the Great Lakes basin.

If ruffe spread beyond western Lake Superior - past an imaginary line between Michigan's Keweenaw Peninsula and Marathon, Ontario - Busiahn said the control program may change because current strategies are specific to the western part of the lake.

In Wisconsin, the state DNR is developing a response plan in case ruffe infiltrate inland waters. DNR officials will finalize the specifics of that plan this spring.

Minnesota Sea Grant is currently planning a major research initiative on the ruffe in cooperation with Wisconsin, Michigan, Ohio and New York Sea Grant programs. The initiative is meant to enhance current understanding of the ruffe infestation and its implications on North America.

- Laurence Wiland

Table of Contents

Ruffe Control Committee Treatment Recommendations

1. Range Reduction: Eliminate reproducing populations on the periphery of the range using chemical piscicides.

2. Ballast Water Management: Prevent the transport of ruffe out of western Lake Superior in the ballast water of ships.

3. Population Investigation: Continue and expand investigations of ruffe populations and affected fish communities to provide information necessary to plan and evaluate control activities.

4. Surveillance: Conduct surveillance sampling in likely locations to find newly established populations of ruffe, and designate a single office to compile collections of ruffe.

5. Predator Evaluation: Continue to study the ruffe's predators in Duluth-Superior Harbor.

6. Education: Educate the public so that ruffe will not be transported, or will be killed or reported if caught by anglers.

Table of Contents

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This page created February 1995
Last updated 21 December 1995. T. Yao and J. Eischens
All contents copyright 1995 University of Wisconsin Sea Grant Institute
Designed by Tina Yao tlyao@seagrant.wisc.edu