Fishhook waterflea latest pest to threaten Lake Erie angling

10/1/2000

Another “sea monster” is poised to rear its ugly head in Lake Erie - if you can see it.

It won't be the lake's version of Nessie, Scotland's fabled Loch Ness monster. But this one eventually may be called Messie.

It is known as Cercopagis pengoi among fisheries scientists, but anglers will call it fishhook waterflea, or other less flattering terms, when it gobs up Lake Erie.

The thing is tiny, only about a half-inch long and most of that is a nearly invisible, filamentous tail. It is clear to milk-white except for a black dot - its eye.

But it could have a monstrous impact if it takes hold and spreads across the lake in blobs that could foul fishing tackle and upset the fishery food-chain. Masses of them are said to look and feel like soggy cotton batten full of black dots.

Originally from eastern Europe, the fishhook waterflea is among a group of organisms called crustaceans, such as shrimp and crayfish. It is destined to become yet another of the pests from overseas that have found their way into the lakes via the St. Lawrence Seaway.

The fishhook was found in Lake Ontario in 1998, and already has troubled anglers there and in New York's Finger Lakes, according to Ohio Sea Grant, which recently profiled this latest invader pest in its Twine Line publication.

“We've been looking for it,” said John Hageman Jr., a Sea Grant agent and manager of Ohio State University's prestigious Stone Laboratory at Put-in-Bay. So far, he added, the waterflea has not turned up.

“We all know that it's a matter of time for those (overseas) ships to pick something up and dump it here.”

Adds the state's Gary Isbell: “There's nothing to stop it from being there (in Lake Erie) now, since it's down east.”

Isbell is executive administrator of fisheries management and research for the Ohio Division of Wildlife and frequently has expressed concern about these “aquatic nuisance species.”

The Great Lakes already are polluted with a shipload of alien invader-pests, including the infamous zebra mussel, the round goby, sea lamprey, and a cousin of the fishhook waterflea called the spiny waterflea. Most have gotten here in the ballast-water holds of overseas ships.

Fisheries scientists are concerned, Sea Grant says, that the fishhook's terrific ability to reproduce will lead to high population densities, especially in Lake Erie, which is the shallowest, southernmost, warmest, and most fertile of the Great Lakes.

The waterflea can eat even smaller animals in the food web, ones critical as food for larval fish. All of these tiny creatures are called zooplankton, but their impact is monumental.

Large populations of fishhooks could end up reducing the growth and survival of important fish species, including walleye and yellow perch.

Alternatively, the waterflea could become an important food-source for fish, but concerns remain that its long hooked tail will be hard for small fish to consume. That is one of the drawbacks with the “spine” of the spiny waterflea as a potential food-source for small fish.

The fishhook's long tail, moreover, is expected to easily snag on fishing line and nets as hundreds of waterfleas clump up on tackle.

Less than a year after it was confirmed in Lake Ontario, the fishhook waterflea was found in New York's Finger Lakes and in Grand Traverse Bay of Lake Michigan and in southern lake Michigan.

Fishermen who think they have found a clump of fishhook waterfleas befouling their tackle should scrape or wash a glob of them into a plastic bag or small jar filled with lake water. Refrigerate or ice the sample, or put it in a jar filled half and half with lake water and rubbing alcohol. That will preserve it. Then contact Ohio Sea Grant of the Ohio Division of Wildlife.

Sea Grant's Hageman, for example, can be reached at 419-285-2341. The wildlife division's Lake Erie Fisheries Research Station at Sandusky can be reached at 419-625-8062.

Isbell, among others, wonders where it all will end, or whether it will end. He fears that another insidious alien invader now established in the upper lakes, the ruffe, could show up on Erie any time.

The ruffe is a perchlike species from Eurasia and has infested the Duluth area of western Lake Superior, disrupting yellow perch and other native fish populations. It also has showed up as near as Thunder Bay in Lake Huron at Alpena, Mich. It could spell big trouble on Lake Erie, especially for yellow perch.

A federal law, the Aquatic Nuisance Species Act of 1996, already requires ballast-water exchange for saltwater ships coming into the Great Lakes. But, Isbell said, 75 to 80 per cent of such ships already legally can declare they are “ballast free” while they retain invader pests in the contaminated, unpumpable sludge in their bilges.

Great Lakes interlake carriers, Isbell added, “are awfully sensitive and don't want to be part of the problem.” They have adopted voluntary guidelines aimed at preventing at least moving pests from port to port among freshwater carriers.

Still, Isbell added, no federal U.S. or Canadian guidelines so far will prevent more pest infestations. It's an issue, he asserted, “that continues to rage.”

He noted that the federal nuisance-species act is set for reauthorization next year in Congress. Reauthorization hearings may present an opportunity to strengthen policies and procedures that will choke the flow of new invader pests.

Commentary: The problem of aquatic nuisance species slowly is heading Great Lakes fisheries toward ruin, as if there were not enough other management issues to tackle.

Invader pests, however, are a fundamental problem. For they are interfering with the ecological balance in the lakes, disrupting established food webs that feed species such as walleye, yellow perch, smallmouth bass, steelhead, king salmon, and others that man has grown to know and love. Not to mention spending billions of dollars annually in pursuit of.

This is a huge, complex problem, well beyond the scope and resources of just states, provinces, or private organizations. It is the just the kind that Big Government - the U.S. and Canadian federal governments - are supposed to be there to handle.

But if federal and international action to date over the last 15 years had been effective, the problem would be in hand. It is not. The coming of the fishhook waterflea is yet another example of that.

The solutions will take big money, not thousand-dollar fixes for megamillion-dollar problems.

Steve Pollick is The Blade's outdoors writer.