New Details on Bat-Killing Fungus

  • In caves where 200 to 300 thousand bats used to hibernate, scientists like Scott Darling have found that this year there are only hundreds. (Photo courtesy of the US Fish and Wildlife Service)

Scientists are racing to find a way to fight-off a fungus that’s killing bats. More than a million bats have died so far. Scientists believe entire hibernating bat species could be wiped out within two decades. Laura Iiyama reports the cause might have come from overseas:

Transcript

Scientists are racing to find a way to fight-off a fungus that’s killing bats. More than a million bats have died so far. Scientists believe entire hibernating bat species could be wiped out within two decades. Laura Iiyama reports the cause might have come from overseas:

Biologist Scott Darling knew something was wrong in a recent winter when he got several calls at his Fish and Wildlife office in Vermont. People told him about hundreds of bats flying in the air and dying in the snow. During winter, the furry mammals should be hibernating.

He went to Aeolus cave. It’s where the bats in the area should be crowded together on the walls and ceiling.

“Aeolus cave became a morgue. Bats freezing to death in clusters just outside the cave entrance. Most of the bats flew out of the cave onto the landscape to certain death.”

Where 200 to 300 thousand bats had hibernated just four years ago, this year there are just a couple hundred.

The dead bats had white nose syndrome.

The white powdery fungus was first noticed on bats in New York State in 2006. It’s spread into Ontario, Canada and as far south as Tennessee.

The fungus is not directly killing the bats.

Thomas Kunz is a professor at Boston University. He suspects the fungus keeps waking-up the hibernating bats.

“It may be simply the irritation from the fungus that is causing, if you have athlete’s feet, it itches.”

Instead of hibernating, surviving on their fat reserves, the bats keep waking-up. They burn off the fat. They get too thin. And they die.

Word spread about the fungus.

Thomas Kunz says some scientists recalled seeing a white fungus on bats elsewhere:

“Bat biologists in Europe have observed and reported that there are bats that do have the fungus although it doesn’t seem to be killing them.”

Scientists think someone visited a cave in Europe. Spores from the fungus got on clothing or shoes. Then that person wore the same shoes or clothing in a cave in the U.S. The spores were picked-up by the bats.

The bats huddle together in hibernation, easily spreading the fungus.

Often 90 percent of the bats are killed-off after the first appearance of the fungus. And Kunz says that may have been what happened to bats in Europe because we don’t find as many bats in European caves as there have been in North American caves:

“Now it’s very possible that in historic times there were large numbers of hibernating bats in Europe and these are the leftovers, these were the survivors that may be resistant to the fungus.”

So the arrival of the fungus may mean US bat species will permanently drop in numbers, like the bats in Europe.

David Blehert (blee-hurt) of the US Geological Survey says if that’s the case, it will be a dramatic change in life in caves in America and Canada.

“Whereas we have hibernation caves with 100 thousand, 300 thousand and even commonly lower ten thousand but those are rather common sites where we’ve seen the fungus decimate up to 95 percent and greater to the animals in the cave. Many of the European hibernation sites have between one and thirty animals.”

There’s no treatment for white nose syndrome. And even if a cure is found, it will be a very long time –centuries– before the bats recover. Bats reproduce slowly. The females have only one pup, one baby bat, per year. And there are over a million bats dead so far.

For The Environment Report, I’m Laura Iiyama.

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Lake Huron’s Invasive Species

  • Filmmaker John Schmit says he wanted to make this film to show how even the smallest invader could mess up the delicate balance of life in the lake. (Photo courtesy of the NOAA GLERL)

You might call Lake Huron the forgotten Great Lake. There are no major cities on its shores. It doesn’t get the media attention the other four Great Lakes do. But its problems are just as bad or worse. Rebecca Williams reports a new documentary tells the story of Lake Huron’s struggle with dozens of alien invaders… and the biologists and fishermen who are trying to reclaim their lake:

Transcript

You might call Lake Huron the forgotten Great Lake. There are no major cities on its shores. It doesn’t get the media attention the other four Great Lakes do. But its problems are just as bad or worse. Rebecca Williams reports a new documentary tells the story of Lake Huron’s struggle with dozens of alien invaders… and the biologists and fishermen who are trying to reclaim their lake:

The documentary Lake Invaders is a cautionary tale about opening the door to strangers. It tells how Lake Huron was opened up to alien invasive species. The film paints fish biologists as the heroes rushing in.

“Seems like it always has to wait until it’s at a disaster level before you know, we can start fixing it… we’re constantly putting out these biological fires, running from fire to fire, to try to keep them under control. We have to find another way to approach this.”

More than 180 non-native species have gotten into the Lakes… and some of them have turned everything upside down. Long, slithering, blood-sucking parasites called sea lamprey were the first to get in. They slipped through a canal that connects the Atlantic Ocean and the Great Lakes. Lamprey killed off most of the big predator fish in the Lakes.

Then… came the alewife. Since the lamprey had taken out the top predators… there was nothing to eat the invading alewives. In the film… biologist Jeff Schaeffer explains how the small fish took over the lakes.

“At that time over 90% of the fish biomass of Lake Michigan and Lake Huron was probably dominated by the exotic alewife. One of my colleagues refers to the Great Lakes at that time as alewife soup.”

Suddenly… there was a major stinking mess. Each spring, hundreds of millions of dead alewives washed up on shore and rotted. Not the best thing for tourism.

Filmmaker John Schmit says he was surprised to learn what happened to the lakes next.

“The funny thing about the Great Lakes is there’s Pacific salmon in them.”

Schmit says biologists brought in millions of salmon from the Northwest to control the alewives. The crazy thing is… it worked. In the film we see how a 4 billion dollar sport fishing industry was born. And the native fish of Lake Huron were pretty much forgotten about.

The salmon fishery boomed for decades. Until the alewives crashed in 2003.

Fisher Doug Niergarth says then… the salmon started starving.

“Two years ago we saw some monster salmon heads that were sitting on little dwarfed bodies. And it was the ugliest thing and rather nasty. Just skinny and withered away. It was the nastiest thing you ever done seen.”

The fishing industry started slipping away. Marinas just scraped by. Tackle shops and motels closed. People finally realized there was something wrong with the lakes.

John Schmit says he wanted to make this film to show how even the smallest invader could mess up everything… both the delicate balance of life in the lake and the people who fish it and depend on money from tourism.

“Lake Huron has been the most impacted by the newest invaders. My personal concern, my investment in the Great Lakes and making this documentary is for people to be aware of the kind of damage invasive species can do to these huge lake systems.”

He says his film Lake Invaders is an example of what invasive creatures can do… not just to Lake Huron… but any ecosystem.

For The Environment Report, I’m Rebecca Williams.

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Wolf Hunting Hurts Wolf Packs

  • The gray wolf is slated to be removed from the Endangered Species List. Many are worried this will have a negative impact on wolf packs. (Photo courtesy of Wisconsin Fish and Wildlife Service)

This year, the U.S. Fish and Wildlife Service plans to officially remove the northern
Rockies gray wolf from the federal Endangered Species List. The agency will hand over
management of the wolves to states in the region. The states will allow hunters and
ranchers to kill wolves during specific seasons, or even year-round. But scientists and
conservationists are concerned about the hunting plans. Kinna Ohman reports some
conservationists think hunting could disrupt the way a wolf pack works, and even lead
members to seek out easier prey such as livestock:

Transcript

This year, the U.S. Fish and Wildlife Service plans to officially remove the northern
Rockies gray wolf from the federal Endangered Species List. The agency will hand over
management of the wolves to states in the region. The states will allow hunters and
ranchers to kill wolves during specific seasons, or even year-round. But scientists and
conservationists are concerned about the hunting plans. Kinna Ohman reports some
conservationists think hunting could disrupt the way a wolf pack works, and even lead
members to seek out easier prey such as livestock:


Biologists in Yellowstone National Park have had an unprecedented opportunity to study
wolves over the last twelve years. They’ve looked at everything from what wolves prefer
to eat, to why wolves kill big prey such as bison. But one topic they haven’t studied
much is how a typical wolf pack works.


Doug Smith is a biologist with Yellowstone’s wolf recovery program. He says they now
understand healthy wolf packs need lots of older, skilled members in order to hunt natural
prey:


“They’re very good at it. They have a lot of teamwork. They switch back and forth
about whose doing what job.”


In fact, studies have shown it takes 3-4 skilled adults to kill an elk. It takes more wolves
to kill a bison. Packs in Yellowstone are naturally filled with large numbers of adults.
But in places where wolves are hunted by humans, skilled adults are in short supply.


Smith says a lack of skilled wolves in a pack could mean they’d be more likely to go after
easier prey including livestock:


“If they don’t have that experienced age structure in the pack, they make do, and so
you will have probably inexperienced killers out there and inexperienced killers are gonna
look for easier prey. The elders of the pack, if there are only 2 or 3 of you,
are much more likely going to go after a sheep or cow than if there’s 7 or 8 of you.”


These concerns could become real when the gray wolf is taken off the Endangered
Species list in the northern Rockies. The states of Montana, Idaho, and Wyoming will
take over management. Suzanne Stone with the Defenders of Wildlife in Idaho says
hundreds of wolves could be killed as part of state management plans:


“They’re talking about killing now about 500 to 600 wolves after delisting. You
don’t manage any population of wildlife like that. The delisting plan, as it’s written
right now, is just a recipe for failure.”


Stone says the gray wolves were protected to build healthy populations, and how a wolf
pack works should be part of that consideration.


But the government is focused on how sport hunting effects just wolf numbers. Ed Bangs
is the wolf recovery coordinator with the U.S. Fish and Wildlife Service. He says that
hunting won’t threaten the wolves:


“One thing that does happen everywhere in the world that wolves and people
overlap is that people kill wolves. And the answer is yes, that does have an effect on
wolf pack structure. And it certainly never endangered wolf populations.”


So it’s hard for conservationists to convince officials that the sport hunting of wolves
could change how wolf packs work and even lead to more livestock conflicts. Biologist
Doug Smith says that’s because the decision to delist the wolves is based purely on
numbers:


“Delisting is entirely numbers. Some conservation biologists have made the
argument that delisting should not occur until the endangered species is integrated
back within the ecosystem and functioning as a member as that ecosystem. That is
not how delisting occurs now for the Fish and Wildlife Service. It’s ‘do we have
enough?'”


Many conservationists and activists will soon be arguing that killing 500 to 600 wolves
leave too few. They’ll likely file lawsuits, stressing that the importance of healthy wolf
packs should be considered before hunting is allowed.


Ed Bangs with the Fish and Wildlife Service says he’s confident the agency has followed
the law. He says they’ll meet the requirements of the Endangered Species Act by
delisting the wolves and handing management over to the states:


“My deal with the Fish and Wildlife Service is: What is the purpose of the act as it’s
currently written by Congress, have we met those conditions for wolves, and the
answer is clearly yes and therefore we’re supposed to delist them. If people want the
act to say something different, they need to talk to their elected officials, not the Fish
and Wildlife Service.”


But the wolf’s defenders will argue the U.S. Fish and Wildlife Service as well as the
states need to understand how the wolf packs work before declaring open season on the
wolf.


For the Environment Report, I’m Kinna Ohman.

Related Links

New Virus in Mississippi River

Fish biologists are worried about a
virus from Europe that is killing fish in the
Mississippi River. Sandra Harris reports:

Transcript

Fish biologists are worried about a virus from Europe that is killing fish in the
Mississippi River. Sandra Harris reports:


Spring Viremia is killing carp in the Mississippi River. Biologists are concerned the
virus could spread to other smaller related fish, called cyprinids, that are used for bait. Ron Benjamin is
a fish biologist with the Wisconsin Department of Natural Resources:


“Right now, we’re not seeing that happen. We see the forest base is pretty stable out there. Like I say, it does affect other cyprinids but it’s to various degrees. And so, at least so far, we haven’t seen that impact.”


Benjamin says Spring Viremia was discovered in the Mississippi in 2002 when
antibodies of the virus were found in carp. It is not harmful to humans who eat the fish.
The virus is thought to have been brought to the United States in goldfish imported from
Europe.


For the Environment Report, I’m Sandra Harris.

Related Links

Invasive Species at the Aquarium

  • Asian carp are one of the invasive species featured in the exhibits in your local museums. (Photo courtesy of USFWS)

Big, public aquariums spend a lot of money to make fish look like they’re at home in the wild. But lately some aquariums are showing fish that are out of place. The GLRC’s Shawn Allee looks at one aquarium’s effort to give them the spotlight, too:

Transcript

Big, public aquariums spend a lot of money to make fish look like
they’re at home in the wild, but lately some aquariums are showing fish
that are out of place. The GLRC’s Shawn Allee looks at one aquarium’s
effort to give them the spotlight, too:


The federal government’s spending millions to keep Asian Carp out of
the Great Lakes. Biologists worry Asian Carp could devastate the lakes’
ecosystem. Recently, though, several carp were brought within sight of
the Great Lakes, and biologists are happy about it.


Chicago’s Shedd Aquarium is on the shore of Lake Michigan. It’s
holding an exhibit of Asian Carp and other alien invasive species.


Curator Kurt Hettinger captured the aquarium’s carp during a trip on an
Illinois river.


“They’re literally jumping, sometimes over the bow of the boat,
sometimes smacking into the side of the boat. I just looked behind me
and was amazed to see all these fish jumping in the wake of the boat, and
to this day, I’m still stunned by this.”


And Hettinger’s more than just stunned. He’s worried.


Asian Carp are an invasive species, basically … pests that crowd out
native fish, and that river where he caught them hooks up to Lake
Michigan.


Again, Asian carp haven’t made it to the Great Lakes, but more than one
hundred and sixty other invasive species have arrived and are breeding
quickly.


One example’s the zebra mussel. At first, scientists worried about how
much money it could cost us. Zebra mussels multiply so fast they can
block pipes that carry cooling water to power plants. But now, we know
the zebra mussel’s disrupting the lakes’ natural food chain.


In other words, invasive species are a huge economic and ecological
nuisance. That’s why the Shedd Aquarium started the exhibit.


“The public I think has seen enough stories about the damages and the
spread and the harmfulness, but those stories are not very often coupled
with solutions.”


That’s ecologist David Lodge. He says the exhibit tries to show how
people spread these species around. Lodge points to one exhibit tank. It
looks like a typical backyard water garden. It’s decked out with a small
fishpond, water lilies, even a little fountain shaped like an angel. It looks
pretty innocent, but Lodge says plants and fish you buy for your own
water garden could be invasive species.


“All those plants and animals that are put outside, then have an
opportunity to spread. Now, it doesn’t happen very often, but with the
number of water gardens, it happens enough so that they are a serious
threat to the spread of species.”


Birds or even a quick flood could move seeds or minnows from your
garden to a nearby lake or river.


The Shedd Aquarium’s not alone in spotlighting invasive species.
Several aquariums and science museums are also getting on board. For example one in
Florida shows how invasive species have infested the Everglades.


Shedd curator George Parsons went far and wide for inspiration.


“I was in Japan last year when we were planning this, and I just
happened to stumble across one of their aquariums and they had an
invasive species exhibit, except that they were talking about large mouth
bass and blue gill. You know, something that is our natives. So, it was
kind of ironic to see that out there. It was kind of neat.”


Like us, the Japanese take invasive species seriously. Back in 1999 the
humble Midwestern Blue Gill created a national uproar. Turns out, they
had taken over ponds throughout the Emperor’s palace, and how did the
bluegill get to Japan?


Probably as a gift from a former Chicago mayor. Apparently, the mayor
thought blue gill might make nice sport fishing in Japan. It was an
innocent mistake, but it’s just the kind of mishap biologists want all of us
to avoid from now on.


For the GLRC, I’m Shawn Allee.

Related Links

Delisting the Bald Eagle

Federal wildlife officials have proposed removing the bald eagle from the endangered species list. In the lower 48 states, bald eagles have recovered from around 400 nesting pairs in the early 1960’s, to more than 7-thousand pairs today. The Great Lakes Radio Consortium’s Erin Toner reports:

Transcript

Federal wildlife officials have proposed removing the bald eagle from
the endangered species list. In the lower 48 states, bald eagles have
recovered from around 400 nesting pairs in the early 1960s, to more than
seven thousand pairs today. The Great Lakes Radio Consortium’s Erin
Toner reports:


Major environmental groups hailed the government’s proposal to remove
the bald eagle from the endangered species list.


Doug Inkley is senior science advisor for the National Wildlife
Federation, which helped lead the bald eagle recovery.


“The success of recovering our nation’s symbol…the bald eagle…
demonstrates that with the right resources and with cooperative action by
all of those involved, the Endangered Species Act does chart a successful
path to recovery.”


The U.S. Fish and Wildlife Service will take public comment until May
17th on the proposed de-listing of the bald eagle. It was added to the
endangered species list in 1967, after becoming nearly extinct because of
the use of the pesticide DDT.


Some biologists are calling the proposed de-listing premature, saying the
bird’s numbers haven’t rebounded everywhere, and that its habitat still
needs protection.


For the GLRC, I’m Erin Toner.

Related Links

Cash Strapped Biologists Lean on Volunteers

  • The lynx was recently considered extinct in Michigan until a trapper caught one. (Photo courtesy of USFWS)

For years, federal and state governments have cut funding for wildlife protection. That’s led to complaints from biologists who say they don’t have enough money to adequately do their jobs, but it’s also led to a new movement. The Great Lakes Radio Consortium’s Celeste Headlee reports on how citizens are starting to take over duties once performed by trained scientists:

Transcript

For years, federal and state governments have cut funding for wildlife
protection. That’s led to complaints from biologists who say they don’t
have enough money to adequately do their jobs, but it’s also led to a new
movement. The Great Lakes Radio Consortium’s Celeste Headlee
reports on how citizens are starting to take over duties once performed by
trained scientists:


Ray Rustem says wildlife biologists these days are often chained to their
desks.


“Years ago, when I first started with the Department of Natural
Resources, wildlife habitat biologists spent quite a bit of time in the field
actually doing fieldwork. With the types of things that are going on now,
they’ve become much more in getting the planning done and we’ve had
to shift some of that fieldwork done to the technician level. Frankly,
yeah, we could always use additional people out there.”


Rustem is with the Wildlife Division of the Michigan Department of
Natural Resources. He says state funding has fallen steadily for years,
and one way he’s made up the difference is by involving Michigan
citizens. Rustem says the DNR uses dozens of volunteers for its frog and
toad survey in the early part of the summer.


“This is our tenth year and we’ve got at least 120 people who’ve been
doing this all ten years. That’s a tremendous amount of data that’s being
provided for us on information about species and where they’re located.”


Many groups are now using so-called citizen scientists to collect data.
Sally Petrella is a biologist who works with the non-profit organization
the Friends of the Detroit River.


“We’ve cut out so much of the funding for regular science that there’s a
real lack, and citizen scientists can cover far more areas than
professionals can, at a much lower cost.”


Petrella is standing beside the murky, reed-choked waters of the Rouge
River Watershed. It’s home to six species of frogs and toads. Every
summer, Friends of the Detroit River enlists the help of 700 people to
listen for the creatures as they call to each other from the marshy
grasses.


Petrella is standing beside one of her more loyal volunteers… Al Sadler.
Sadler admits that part of the appeal is the walk along the banks of the
river… but he also believes that public participation in wildlife
protection has become an absolute necessity.


“I think that it’s required if we plan on keeping any wildlife areas
around. I think that if citizens don’t get involved, I think that people
won’t know what they’re going to miss, and before we know it, there
won’t be much wild places left.”


Sadler is a fairly typical citizen scientist. He has a day job as an engineer
and volunteers in his spare time, but there are also people with advanced
degrees in biology and wildlife management who are called citizen
scientists simply because they don’t work for the government.


Dennis Fijakowski is one of those people. He’s the executive director of
the Michigan Wildlife Conservancy.


“We can’t count on the government to do everything for us. We have to
be a part of the solution.”


Fijakowski says ordinary people have made important contributions to
wildlife conservation. He says the lynx was considered extinct in
Michigan until a trapper caught one, and a rare Great Gray Owl was
discovered on a national wildlife refuge last spring by a photographer.


“You look back at the conservation history of our state and it was citizen
led. All of the important, the milestone decisions, legislation… it was
citizen led.”


John Kostyack with the National Wildlife Federation says involving
citizen scientists is great, but…


“They’re not really a substitute for having staff in the wildlife agencies…
state and federal and tribal. Because they are the ones who are going to
take this initial data, which is going to be very rough from volunteers,
and then use it to decide upon where to take the research next.”


And there have been cases in which citizen scientists have clashed with
state and federal governments. They are consistently at odds with government
officials over issues related to global warming and the Michigan Wildlife
Conservancy is locked in a bitter battle with state biologists over whether
the state is home to a viable cougar population.


The Conservancy’s Dennis Fijakowski acknowledges that the union
between government biologists and citizen scientists may not always be
an easy one, but he says the involvement of residents in the protection of
their state’s wildlife can only be a good thing.


“Because all anyone of us wants is that we pass on a wild legacy to our
children and grandchildren… and we’re not going to if we don’t get our
acts together.”


Many organizations offer citizens the opportunity to get involved in data
collection, including the U.S. Fish and Wildlife Service.


For the GLRC, I’m Celeste Headlee.

Related Links

Whooping Cranes Following by Example

Researchers began a program to reintroduce whooping cranes in the eastern U.S. in 2000. This winter, some young cranes are learning how to migrate south from older birds. The biologists tracking the birds say so far, the new recruits are catching on. The Great Lakes Radio Consortium’s Christina Shockley reports:

Transcript

Researchers began a program to reintroduce whooping cranes in the
eastern U.S. in 2000. This winter, some young cranes are learning how
to migrate south from older birds. The biologists tracking the birds say
so far, the new recruits are catching on. The Great Lakes Radio
Consortium’s Christina Shockley reports:


At first, humans led the new flock of whooping cranes from Wisconsin
to Florida by flying ultra light planes. Now, some of those birds are
teaching a few younger cranes how to make the trip.


Kelley Tucker is with the International Crane Foundation, one of the
groups involved in the reintroduction project. She says this winter, four
young whooping cranes are flying with older cranes and sandhill cranes
on the migratory path. They’re relying partly on instinct, partly on the
lead of the older birds.


“The birds will be a couple miles apart, but some of the biologists have
said ‘I have a sense that the younger birds know where the older birds
are.’ Sometimes they’ll roost within a mile or two of the older birds.”


Tucker says eventually she hopes all the chicks will learn to migrate
from older birds, and the ultra light planes won’t be used. She says it’s
important for the cranes to make it back to Wisconsin in the spring to
mate.


For the GLRC, I’m Christina Shockley.

Related Links

Ten Threats: Break in the Food Chain?

  • Diporeia are disappearing from Lakes Michigan, Huron, Erie, and Ontario. The actual size of a diporeia is ½ an inch. (Courtesy of the EPA)

Some of the life in the Great Lakes has been hit hard by industry and trade. Pollution and
invasive species have hurt some of the native plants and animals important to the food
chain. While popular game fish might be the first to come to mind, it’s a little organism
at the bottom of the food chain that has biologists and fishing experts most concerned.
The Great Lakes Radio Consortium’s Lester Graham reports:

Transcript

In a survey, experts said one of the Ten Threats to the Great Lakes is a disappearing
species. Some native fish populations and organisms are declining. Our guide through
the Ten Threats series is Lester Graham.


Some of the life in the Great Lakes has been hit hard by industry and trade. Pollution and
invasive species have hurt some of the native plants and animals important to the food
chain. While popular game fish might be the first to come to mind, it’s a little organism
at the bottom of the food chain that has biologists and fishing experts most concerned.
The Great Lakes Radio Consortium’s Lester Graham reports:


(Sound of swinging doors)


Jack Donlan is taking me behind the fish counter at Donlan’s Fish House. In the
backroom he’s scaling and filleting some whitefish.


“Of the fishes caught in the Great Lakes, whitefish is one of the big volume fishes. Lake
perch, walleye bring more money per pound, but I would think from a tonnage-wise,
whitefish, it’s an extremely popular fish.”


This is a popular place to get Great Lakes fish, but Donlan’s suppliers, the commercial
fishers, are worried about the catch. At some places in the Great Lakes whitefish aren’t
doing too well.


(Sound of Lake Guardian motors)


Tom Nalepa is trying to figure out why whitefish are struggling. He’s onboard the U.S.
Environmental Protection Agency research ship, the Lake Guardian. Nalepa is a
biologist with the National Oceanic and Atmospheric Administration’s Great Lakes
Environmental Research Lab. He’s been studying Lakes Michigan and Huron, and on
this day he’s getting ready to study the bottom of Lake Erie.


He’s not studying whitefish. He’s actually looking for a tiny shrimp-like crustacean, only an
eighth to a quarter inch long, called diporeia. Eighty-percent of the whitefish diet is
made up of diporeia.


“And what we’re seeing is a dramatic drop in populations, and not only drops, but there are
large areas now in all the lakes, except Lake Superior, that no longer have diporeia. This
is real concern because diporeia is a very important fish food.”


Researchers used to find eight to 10-thousand diporeia or more in a square meter of sediment just
a few years ago. Now, there are only a dozen or so, or none at all. Diporeia is one of the
mainstays of the bottom of the food chain, and Nalepa says whitefish aren’t the only ones
that eat the tiny critters in the sediment at the bottom of the lakes.


“Just about every type of species found in the Great Lakes will feed on diporeia at some
stage in its life-cycle. Diporeia is high in calories and has a high-energy content. It’s a
very good food, nutritious food source for fish.”


Without it, fish are not getting enough to eat. Marc Gaden is with the Great Lakes
Fishery Commission. He says when diporeia disappears, commercial fishers can’t help
but notice.


“Right now we’re seeing skinnier whitefish. Whitefish that are somewhat emaciated in
some areas because they just don’t have as much of these low-end of the food web organisms
to eat, and we think it’s related to an invasive species that came in.”


That invasive species is the zebra mussel, and more recently another invader that was
likely carried to the lakes in the ballasts of ocean-going cargo ships, the quagga mussels.


Back on the Lake Guardian, Tom Nalepa says he’s seen the connection again and again.


“There’s no question that it’s related to zebra mussels and quagga mussels. In every area
that we’ve studied, regardless of the lake area, declines were happening a couple of years
after the quagga mussel or zebra mussel were first found, but that connection remains
elusive.”


Biologists thought the invasive mussels might have been filtering out all of the food the
diporeia eat, but when they find diporeia, they don’t appear to be starving. They appear
healthy. Now, scientists are wondering if there’s some kind of disease or toxin spread
by the mussels that’s wiping out the diporeia.


Even if researchers learn why the diporeia are disappearing, there might be nothing that
can be done to help. Some scientists worry that the decline of diporeia and other
organisms at the base of the food chain might ultimately lead to a massive collapse of fish
stocks in the Great Lakes.


For the GLRC, this is Lester Graham.

Related Links

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.

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