Invasive Die-Off Stirs Fishery Debate

  • A naturally reproduced wild lake trout fingerling. (Photo courtesy of MI DNR.)

The fisheries in the Great Lakes are seeing dramatic changes. In one lake, an invasive species that has become part of the food chain has collapsed. But some native fish are doing better because of that collapse. Lester Graham reports some fishery managers are debating what to do next:

Transcript

The fisheries in the Great Lakes are seeing dramatic changes. In one lake, an invasive species that has become part of the food chain has collapsed. But, some native fish are doing better because of that collapse. Lester Graham reports some fishery managers are debating what to do next:


When we started digging canals, connecting the lakes to the Atlantic Ocean, things changed a lot for the fish in the Great Lakes.


First, the sea lamprey got into the lakes through the Welland canal that bypasses Niagara Falls.


The lamprey is an eel-like parasite that nearly wiped out the big fish in the Great Lakes by attaching to them and sucking the life out of them.

Also slipping through the canals was a smaller fish, the alewife. Since the lamprey wiped out most of the predator fish in the lakes, the alewife population exploded. They out-competed native fish for food. It got so bad, that by the mid 1960s, if you weighed all the fish in Lake Michigan, more than 80% of the weight would have been alewives.


So, once wildlife managers got the sea lamprey under control, they had to figure out what they could do to get alewives under control. The fish biologists decided to introduce new predators, trout and salmon, to prey on the alewives. These fish were not native to the Great Lakes. Expensive nurseries were built by federal and state game agencies to keep supplying new trout and salmon every year to prey on alewives.


Forty years later, in Lake Huron, the alewife population collapsed, and in Lake Michigan alewives are declining rapidly. Mission accomplished, right?


Well, in that 40 years, a whole recreational fishing industry has grown up around fishing for those introduced trout and salmon. Some fishery managers now say we have to find a balance of the right amount of alewives to sustain the introduced trout and salmon fishery. So, recently states have cut their trout and salmon stocking programs to give alewives a chance to recover.


Tom Trudeau [who] operates a fish nursery for the state of Illinois says it would cause trouble to try to take the Great Lakes back to native fish only.


“We do have this industry that we have pressure to keep. You know, you’re putting a lot of people out of business if you get rid of it.”


And Trudeau says because of ecological damage, many of the smaller native fish on which big predators used to feed have been wiped out.


“So, I mean, of the six or seven species in that category, we only have one. And a couple of them are extinct. So, I mean, we could talk about going back to the ideal situation of pure native species, but we’ve disrupted the habitat so much.”


So, the argument goes, the invasive alewives are now needed. But something unexpected happened when the alewives disappeared from Lake Huron. The native fish, walleye, yellow perch, and lake trout started doing better.


Dave Fielder is a fisheries research biologist with the Michigan Department of Natural Resources.


“We’ve long known that adult alewives were a predator and a competitor on newly hatched perch and walleye fry. We just didn’t realize how substantial that effect was until finally the adult alewives were removed from the system and now we’re enjoying some greatly increased reproductive success. Walleye, particularly in Saginaw bay, are at some of the highest levels that we’ve seen in a long time.”


But, after 40 years, people are used to fishing for those introduced trout and salmon. And some fisheries managers are wondering what will happen to all those expensive nurseries that provide their jobs.


What happens to all of those charter boat fishing operations, fishing tourism, if the government were to stop stocking those trout and salmon? Would they switch to fishing for native fish? And, can the native fish even survive in the long-run since so many of the smaller native prey-fish are no longer around?


Dave Fielder says it’s hard to say.


“So, we’re kind of in the middle of a change – it’s really a paradigm shift in many ways – and that’s always scary because nobody really knows how we’re going to end up, but I prefer to be optimistic. I think there are a lot of reasons to be hopeful in regards to the benefits that we’re seeing for our native species.”


But some fisheries managers say the debate of whether to go all native or to try to find the right mix of native and non-native fish is not over. Since invasive species, pollution, and habitat destruction have changed the Great Lakes so much, wildlife managers think they’ll still have to keep stocking one kind of fish or another to keep the recreational fishing industry going. If that’s the case, does it matter whether it’s native fish, or the introduced fish that anglers have grown to like so much?


For the Environment Report, this is Lester Graham.

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Yellow Perch Making Resurgence?

A popular fish might be making a comeback in the upper Great Lakes. Yellow perch were once a favorite catch for sport and commercial fishermen, but their populations crashed in the 1990’s. Biologists say new surveys in Lakes Huron and Michigan have found huge numbers of young perch. The GLRC’s Peter Payette reports:

Transcript

A popular fish might be making a comeback in the upper Great Lakes.
Yellow Perch were once a favorite catch for sport and commercial
fishermen, but their populations crashed in the 1990’s. Biologists say
new surveys in Lakes Huron and Michigan have found huge numbers of
young perch. The GLRC’s Peter Payette reports:


A survey of Lake Michigan found more perch were born last year than in
the best years on record. Two or three times as many.


Recent studies of perch in Lake Huron’s Saginaw Bay have shown
similar results. It’s not clear why fish numbers would suddenly
skyrocket. Weather is believed to be one factor.


Dave Fielder is a biologist with the Michigan DNR. He says perch in
Lake Huron have also benefited from the decline of alewives, which are
an invasive species.


“We’ve known for a long time that alewives are formidable predators and
competitors on newly hatched yellow perch fry.”


Fielder says most of the newborn perch are not surviving so the adult
population in Saginaw Bay has not grown. He says it may be too many
perch have been born and there’s not enough food for them all.


For the GLRC, I’m Peter Payette.

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Ten Threats: Wetlands – Where Life Begins

  • Great Lakes coastal wetlands filter water, give lots of wildlife a place to live and help prevent erosion. These wetlands are also greatly responsible for feeding the fish of the Great Lakes. (Photo by Lester Graham)

The Ten Threats to the Great Lakes were identified for us by experts from all over the region.
Again and again they stressed that the shores and wetlands along the lakes were critical to the
well-being of the lakes and the life in them. Great Lakes coastal wetlands filter water, give lots of
wildlife a place to live and help prevent erosion. But the coastal wetlands are also greatly
responsible for feeding the fish of the Great Lakes. Biologists are finding that when people try to
get rid of the wetlands between them and their view of the lake, it hurts the fish populations.
Reporter Chris McCarus takes us to where life begins in the lakes:

Transcript

We’ve been bringing you the series, Ten Threats to the Great Lakes. One of the
keys to the health of the lakes is the connection between the lakes and the land.
The Great Lakes Radio Consortium’s Lester Graham is our guide through the series:


The Ten Threats to the Great Lakes were identified for us by experts from all over the region.
Again and again they stressed that the shores and wetlands along the lakes were critical to the
well-being of the lakes and the life in them. Great Lakes coastal wetlands filter water, give lots of
wildlife a place to live and help prevent erosion. But the coastal wetlands are also greatly
responsible for feeding the fish of the Great Lakes. Biologists are finding that when people try to
get rid of the wetlands between them and their view of the lake, it hurts the fish populations.
Reporter Chris McCarus takes us to where life begins in the lakes:


(sound of walking in water)


About a dozen researchers have come to Saginaw Bay off of Lake Huron. They walk from the
front yard of a cottage into some tall grass and black mud out back. The coastal wetland is wide
here.


Don Uzarski is a professor from Grand Valley State University. He wants to see just how many
different kinds of microorganisms live in this wetland. He asks a colleague to dip a fine mesh net
into the muck.


“Why don’t you give us your best scoop there…”


The net’s contents are poured into a tray. The water and muck is pushed aside and tiny animals
are revealed. None of them is any bigger than an inch.


“There are a lot organisms right there. That’s a lot of fish food. Lot of water boatmen. We have
scuds swimming through here. We have snails. Probably a bloodworm. I don’t see it. But the
red thing.”


Uzarski says this is a healthy patch of wetland. It’s where Great Lakes life begins.


“The whole community starts here. And we’re talking about everything from the birds and fish
and all the things that people tend to care about more. But without this stuff we don’t have
anything.”


These microorganisms are at the bottom of the food chain. Lake trout, walleye and salmon are at
the top. But this natural order has been disturbed by humans. Only parts of the wetland are able
to work as nature intended. The bugs, snails and worms are supposed to be everywhere here. But
Uzarski says they’re not.


“Look at if we take 20 steps over there we’re not going to find the same thing. It’s gonna be
gone. And where’s that coming from? It’s coming from these disturbed edges. Which were
disturbed by? It was the spoils from dredging out that ditch right there.”


The dredging material is piled along the edge… a bit like a dike. Uzarski says that’s one of the
three main threats to coastal wetlands.


The dikes stop the natural flow of water. Farm and lawn fertilizers, sediment and chemical
pollution are not filtered out when they run off the land. Dikes also stop the water from carrying
food for fish out into the lake… and in the other direction, water can’t bring oxygen from the lake
into the wetlands. They’re at risk of becoming stagnant pools.


A second threat to the wetlands is alien invasive plants. Ornamental plants intended for gardens
have escaped. Phragmites, purple loosestrife, and European water milfoil among others all choke
out the native plants that help make the wetland systems work.


But… the greatest threat to the coastal wetlands is construction. We’ve been building homes,
buildings and parking lots right over the top of some of the Great Lakes’ most critical wetlands.


Sam Washington is Executive Director of the Michigan United Conservation Clubs, the state’s
largest hunting and fishing advocacy group. He says we need healthy wetlands if we want to
keep fishing the Great Lakes.


“If we didn’t have wetlands, if we didn’t have the ability to regenerate the bottom foods in the
food cycle of these animals, we wouldn’t have the big fish that people go out in the Great Lakes
to catch everyday. They just wouldn’t be there.”


Washington says the way to fix the problem is easy… but it will require us to do something that
comes really hard…


“The best thing human beings can do for wetlands, even though we really believe we know how
to fix everything, is just to leave ’em alone.”


Sam Washington gets support from the biologists who tromp out into the wetlands. They say
we’ve got to protect the whole food chain… so we should leave wetlands alone and just let nature
do its job.


For the GLRC, I’m Chris McCarus.

Related Links

Ten Threats: Dead Zones in the Lakes

  • These fishermen at Port Clinton, Ohio, are a few miles away from the dead zone that develops in Lake Erie every summer... so far, most fish can swim away from the dead zone. But the dead zone is affecting the things that live at the bottom of the lake. (Photo by Lester Graham)

One of the Ten Threats to the Great Lakes is nonpoint source pollution. That’s pollution that
doesn’t come from the end of a pipe. It’s oil washed off parking lots by storms, or pesticides and
fertilizers washed from farm fields. Nonpoint source pollution might be part of the reason why
some shallow areas in the Great Lakes are afflicted by so-called dead zones every summer.

Transcript

In another report on the Ten Threats to the Great Lakes series, reporter Lester Graham looks at a
growing problem that has scientists baffled:


One of the Ten Threats to the Great Lakes is nonpoint source pollution. That’s pollution that
doesn’t come from the end of a pipe. It’s oil washed off parking lots by storms, or pesticides and
fertilizers washed from farm fields. Nonpoint source pollution might be part of the reason why
some shallow areas in the Great Lakes are afflicted by so-called dead zones every summer.


Dead zones are places where there’s little or no oxygen. A dead zone develops in Lake Erie
almost every summer. It was once thought that the problem was mostly solved. But, it’s become
worse in recent years.


(sound of moorings creaking)


The Environmental Protection Agency’s research ship, the Lake Guardian, is tied up at a dock at
the Port of Cleveland. Nathan Hawley and his crew are loading gear, getting ready for a five day
cruise to check some equipment that measures a dead zone along the central basin of Lake Erie.


“What I have out here is a series of bottom-resting moorings that are collecting time series data of
currents and water temperature and periodically we have to come out here and clean them off and
we take that opportunity to dump the data as well.”


Hawley is gathering the data for scientists at several universities and the National Oceanic and
Atmospheric Administration’s Great Lakes Environmental Research Lab. The information helps
them measure the behavior of the dead zone that occurs nearly every year in Lake Erie…


“What we’re trying to do this year is get a more comprehensive picture of how big this low-oxygen zone is and how it changes with time over the year.”


One of the scientists who’ll be pouring over the data is Brian Eadie. He’s a senior scientist with
NOAA’s Great Lakes Environmental Research Lab. He says Lake Erie’s dead zone is a place
where most life can’t survive…


“We’re talking about near the bottom where all or most of the oxygen has been consumed so
there’s nothing for animals to breathe down there, fish or smaller animals.”


Lester Graham: “So, those things that can swim out of the way, do and those that can’t…”


Brian Eadie: “Die.”


The dead zone has been around since at least the 1930’s. It got really bad when there was a huge
increase in the amount of nutrients entering the lake. Some of the nutrients came from sewage,
some from farm fertilizers and some from detergents. The nutrients, chiefly phosphorous, fed an
explosion in algae growth. The algae died, dropped to the bottom of the lake and rotted. That
process robbed the bottom of oxygen. Meanwhile, as spring and summer warmed the surface of
Lake Erie, a thermal barrier was created that trapped the oxygen-depleted water on the bottom.


After clean water laws were passed, sewage treatment plants were built, phosphorous was banned
from most detergents, and better methods to remove phosphorous from industrial applications
were put in place.


Phosphorous was reduced to a third of what it had been. But Brian Eadie says since then
something has changed.


“The concentration of nutrients in the central basin the last few years has actually been going up.
We don’t understand why that’s happening.”


Eadie says there are some theories. Wastewater from sewage plants might be meeting pollution
restrictions, but as cities and suburbs grow, there’s just a lot more of it getting discharged. More
volume means more phosphorous.


It could be that tributaries that are watersheds for farmland are seeing increased phosphorous. Or
it could be that the invasive species, zebra mussel, has dramatically altered the ecology of the
lakes. More nutrients might be getting trapped at the bottom, feeding bacteria that use up oxygen
instead of the nutrients getting taken up into the food chain.


Whatever is happening, environmentalists are hopeful that the scientists figure it out soon.


Andy Buchsbaum heads up the Great Lakes office of the National Wildlife Federation. He says
the dead zone in the bottom of the lake affects the entire lake’s productivity.


“If you’re removing the oxygen there, for whatever reason, for any period of time, you’ve
completely thrown that whole system out of balance. It’s all out of whack. It could mean
irreversible and devastating change to the entire ecosystem.”


And Buchsbaum says the central basin of Lake Erie is not the only place where we’re seeing this
low-oxygen problem…


“What makes the dead zone in Lake Erie even more alarming is that we’re seeing similar dead
zones appearing in Saginaw Bay which is on Lake Huron and Green Bay in Lake Michigan.
There, too, scientists don’t know what’s causing the problem. But, they’re already seeing
potentially catastrophic effects on aquatic life there.”


State and federal agencies and several universities are looking at the Lake Erie dead zone to try to
figure out what’s going on there. Once they do… then the battle likely will be getting
government to do what’s necessary to fix the problem.


For the GLRC, this is Lester Graham.

Related Links

New Lakeshore Wetlands: Nuisance or Asset?

  • Terry Miller, of the Lone Tree Council, is one of the few Bay City residents trying to protect wetlands sprouting up along the beaches of Saginaw Bay. Many of his neighbors prefer beaches with less vegetation. Photo by Steve Meador.

With water levels below-average in the Great Lakes, emergent wetlands are flourishing in many large, protected bays. This thick vegetation, a few hundred yards wide at most, fringes the shoreline of exposed lakebeds. Scientists and government officials say emergent wetlands are valuable resources worth protecting. Others say the vegetation is a nuisance and want it destroyed. The Great Lakes Radio Consortium’s Steve Meador has more:

Transcript

With water levels below-average in the Great Lakes, emergent wetlands are flourishing in
many large, protected bays. This thick vegetation, a few hundred yards wide at most,
fringes the shoreline of exposed lakebeds. Scientists and government officials say
emergent wetlands are valuable resources worth protecting. Others say the vegetation is
a nuisance and want it destroyed. The Great Lakes Radio Consortium’s Steve Meador
has more:


There’s a dull gray sky over Saginaw Bay, a large, shallow arm of Lake Huron. A brisk
wind blows off the bay toward Bay City State Park.


“This is the area that bathers come to in the summer, and as you can see, there is only a
small portion of the beach left, that much of the rest has reverted to fairly high levels of
vegetation…cattails…bulrushes… lots of vegetation.”


Terry Miller heads an environmental organization in Bay City called the Lone Tree
Council. These days, Lone Tree is an appropriate description of Miller. He’s one of the
few locals trying to protect emergent wetlands. These wetlands remain mostly out of
mind during cycles of high water. However, with Lake Huron near its lowest level in
decades, thin bands of emergent wetlands now flourish along the shores of Saginaw Bay.


Scientists call these wetlands some of the most productive in the country because they
provide critical habitat for fish and birds. Yellow perch and northern pike use them as
breeding areas, and waterfowl feed and nest there. The wetlands also reduce coastal
erosion by anchoring shoreline sediment during storms.


Terry Miller sees the value of emergent wetlands and is fighting to protect them. He also
accepts that some people are less concerned with how wetlands benefit an ecosystem than
they are with clean, sandy beaches or an unobstructed view of Saginaw Bay.


“As you can see, some of this vegetation is taller than we are, and if you’re a homeowner
sitting back in your coffee hutch looking out and not seeing water but greenery, some
may find that pleasant, but more than likely they would prefer to see the water.”


One local resident who doesn’t like the wetlands is Ernie Krygier. He says the vegetation
reduces property values and prevents access to the water. Worst of all, he says it ruins
sandy beaches, like the one at Bay City State Park.


“This park used to be just jammed, you see all the parking lot space that’s out here, you
couldn’t find a spot back when we had beaches. Now you could shoot a gun through here
and not hit anybody.”


Krygier wants the vegetation along the park’s shoreline removed. He says the place for
wildlife is in the nearby Tobico Marsh, away from park users.


“This is where people belong, that’s where nature belongs.”


Krygier’s issue with the park is part of a larger conflict with government regulators that
also involves private property. The dispute has been dubbed the “weed war” by a
property rights group called Save Our Shoreline, or SOS, that Krygier heads up.


SOS members say they have the right to remove vegetation below the ordinary high
water mark. That’s land the state and federal government says is publicly-owned
bottomland. Government regulators protect this land by requiring permits for
mechanized activities like plowing or grading. This helps preserve the dense root mat
that anchors the shoreline.


Some less destructive techniques for controlling vegetation are allowed without a permit,
including mowing, weed-whacking, and hand-pulling vegetation. Nevertheless, many
property owners have used tractors and other heavy machinery to destroy vegetation on
public land without a permit. Government regulators say this is a violation of the Clean
Water Act. They’ve sent “cease and desist” letters to many property owners, including
one state legislator.


Krygier’s main contention is that property owners have ownership rights to the water’s
edge.


“The government, the state of Michigan wants to take ownership of our property, and that
is wrong. We feel we have the law on our side.”


Some law experts say Krygier’s interpretation is wrong. Chris Shafer is a professor at
Thomas M. Cooley School of Law in Lansing. He’s had some experience in this area.
He ran the Great Lakes Shorelands program for the Michigan Department of Natural
Resources for more than 15 years.


“I think the law is real clear on this, that all of the land we’re talking about below the
ordinary high water mark on the Great Lakes is owned by the state of Michigan. It’s held
in trust for all nine million citizens of Michigan.”


Shafer says that while property owners have some legitimate concerns, they don’t own
the land out to the water’s edge as they believe. They have a right to access the water, but
no right to destroy vegetation on public land.


Shafer says that, unlike the sand dune shores of Lake Michigan, it may be unrealistic to
expect sandy beaches throughout Saginaw Bay. Dr. Thomas Burton agrees. He’s a
professor of fisheries and zoology at Michigan State University who studies wetland
ecosystems.


Burton says emergent wetlands have always been an important part of Saginaw Bay, and
that they naturally grow and recede as water levels fall and rise. He says wetlands are a
vanishing resource along the Great Lakes, and that the small portion of coastline that’s
not sandy beach should be protected. Burton says property owners are missing the bigger
picture.


“To call it a ‘weed war’ to me is very short sighted, and really says that the person doesn’t
either, A. understand the importance of these wetlands, or B. they just don’t care about
nature at all, and are willing to destroy it just so they have a sandy beach in front of their
house, and my own opinion is that that’s a pretty lousy way to look at nature.”


Back in Saginaw Bay, Terry Miller says his crusade to protect emergent wetlands is a
lonely one, especially when neighbors tell him he’s one of the most hated people on the
beach. He says these wetlands are held in the public trust to benefit everyone who uses
the bay, and hopes that some day the effort expended by property owners will be
redirected.


“And the sad thing, the thing that I find very frustrating is that, from an environmental
perspective, our Saginaw Bay is hurting. There are a host of environmental problems that
this energy could be directed at, but it’s not.”


For now, property owners are putting their energy into changing state law. A bill before
the Michigan legislature backed by SOS would allow unpermitted destruction of wetland
vegetation on publicly-owned lands.


For the Great Lakes Radio Consortium, I’m Steve Meador.