Tag: food chain

Bird and Fish Poisoning Spreads in Great Lakes

  • Botulism is killing fish and the shorebirds that eat them. The cause is likely due to a disruption in the ecosystem by invasive zebra and quagga mussels. (Photo by Lester Graham)

A deadly toxin is killing fish and birds along the Great Lakes shoreline.
Researchers think type-E botulism works its way up the food chain from
the bottom of the lake through several invasive species. Bob Allen
reports:

Transcript

A deadly toxin is killing fish and birds along the Great Lakes shoreline.
Researchers think type-E botulism works its way up the food chain from
the bottom of the lake through several invasive species. Bob Allen
reports:


These days, Ken Hyde dreads walking the pristine sandy beaches along
the Sleeping Bear Dunes. He’s the biologist in this national lakeshore
along the Michigan coast, and he only has to hike maybe a hundred feet
to find a dead bird twisted head down and half-buried in the sand:


“This is a cormorant. Just in the last two or three weeks we’re
starting to see a lot more of them. So they’re probably starting to
migrate down from the upper parts of the lake.”



Last year botulism killed over 2,500 dead birds along this 35 mile stretch
of shoreline, mostly gulls and diving ducks, including nearly 200 loons
migrating south from Canada.


This year the die-offs started earlier in the summer and struck more
species. The park lost four endangered piping plovers. The National Park
Service brought in a research team from Minnesota to look for answers.
They’ve been diving in the lakeshore now for two years.


What they’ve found is a huge shoal stretching more than a mile off shore.
It’s covered with native green algae and loaded with invasive zebra and
quagga mussels:


The Park’s research boat docks at a small village along Lake Michigan.
Dive team leader Brenda Moraska Lafrancois was surprised when she
first saw the underwater landscape:


“Last year when we first dove this area we went down and it was
shocking how little of the biomass down there was native. I think
we’re looking at a really altered system.”


Here’s what researchers know so far. The mussels filter nutrients from
the water, the clearer water allows more sunlight to reach the bottom, and
that spurs more algae growth. For good measure, the mussels excrete
phosphorus, in effect fertilizing the algae in the near shore zone. When
millions of mussels and big globs of algae begin to decompose, that uses up
most of the oxygen in water near the bottom of the lake, and that’s a
condition just right for a naturally occurring botulism to grow.


So how does the botulism migrate from the bottom to the surface and
poison shorebirds? Enter the round goby. It’s a small invasive fish that
comes from the same Caspian Sea area where zebra mussels originated.


Last year the research team at Sleeping Bear saw gobies in some places.
Now, says Byron Carnes, everywhere they looked when diving on algae
beds there solid sheets of mussels and blankets of gobies, and he
watched them feeding on mussels:


“Part of the zebra quagga mussel that is the juiciest these guys tend
to go right in and do this frenzy feeding where they just come in and
start pounding away at all the broken shells and trying to get out as
much of the good stuff inside the quagga mussel as they possibly
can.”


Mussels don’t have a nervous system, so they aren’t harmed by botulism
toxin. But when gobies get a dose they flop around on the surface for a
day or so while succumbing, and that’s when shorebirds pick up an easy
but potentially deadly meal.


Some diving ducks may also get poisoned by feeding directly on the
mussels. That’s the theory most scientists in the field think explains
what’s happening, but Harvey Bootsma says it’s not active all the time, so
it’s hard to prove each step. He’s with the Great Lakes Water Institute in
Milwaukee:


“I think the problem is it’s usually a sporadic and short-lived event
when this occurs. And unless somebody happens to be fortuitously
collecting the right samples at the right place and the right time it”s
very difficult to pin down the process as it’s occurring.”



While researchers try to pin down the effects of invasive species in one
place, the cycle spins off somewhere else. This fall there are half as
many dead birds along the Sleeping Bear Dunes shore as last year, but
the die-off is now spreading farther north along the Lake Michigan coast,
and there have been similar outbreaks along Lakes Erie and Huron.


So far Harvey Bootsma says there are no good solutions to break the
cycle of algae, mussels and gobies that scientists think is transporting
botulism toxin to shorebirds.


“And it’s just a great example of how huge an impact a new species
can have on an ecosystem. And I think it makes it all the more
imperative that we try to stem the tide of exotic species coming into
the Great Lakes.”


Researchers say it may take decades for the Great Lakes to recover from
the effects, if they ever do.


For the Environment Report, I’m Bob Allen.

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Toxin Kills Endangered Birds

  • A poisoned seagull on a Lake Erie Beach. Type-E botulism is spreading up the food chain and killing birds on the endangered species list. (Photo by Lester Graham)

A toxin that has killed tens of thousands of shorebirds throughout
the Great Lakes is back. Type-E botulism is spread up the food
chain by invasive species. And as Bob Allen reports, the toxin
recently killed four birds on the endangered species list:

Transcript

A toxin that has killed tens of thousands of shorebirds throughout
the Great Lakes is back. Type E botulism is spread up the food
chain by invasive species. And as Bob Allen reports, the toxin
recently killed four birds on the endangered species list:


There are just 60 pairs of piping plovers known in the Great
Lakes. Many of them breed along the shores of Lake Michigan.


Wildlife officials protect nesting plovers by putting up fences to
keep predators away, but they can’t keep the tiny shorebirds from
eating insects as they skitter up and down the beach. The insects
can pass on Type E botulism to the endangered birds.


Biologist Ken Hyde says the toxin gets into the food chain
through fish – primarily round gobies – that feed on algae and the
invasive zebra and quagga mussels.


“Yeah, we’ve got some pretty good evidence that it’s this cycle of
the algae and then the mussels and the gobies feeding on them
and then primarily gobies coming to the surface that our native
water birds are feeding on.”


Wildlife officials expect to see a lot more dead shorebirds as
the summer progresses.


Type E botulism is not a threat to humans.


For the Environment Report, I’m Bob Allen.

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Citizen Lawsuit Targets Foreign Ships

  • Ocean vessel loading grain at elevator in Superior, Wisconsin. Nine foreign ships have been identified in the lawsuit against international shipping companies. (Photo by Jerry Bielicki, USACOE)

For decades foreign ships have brought tiny stowaways – called invasive
species – into the United States. And once they get loose, they upend
ecosystems and cause billions of dollars in damage. The shipping
industry has yet to seriously address the problem, and now conservation
and environmental groups are suing the companies they say are most at
fault. Mark Brush has more:

Transcript

For decades foreign ships have brought tiny stowaways – called invasive
species – into the United States. And once they get loose, they upend
ecosystems and cause billions of dollars in damage. The shipping
industry has yet to seriously address the problem, and now conservation
and environmental groups are suing the companies they say are most at
fault. Mark Brush has more:


In 1988, the now infamous zebra mussel slipped out of a ship’s ballast
tank near Detroit. It didn’t take long for it to spread, first
throughout the Great Lakes, then through the Ohio and Mississpi rivers,
then on to Alabama and Oklahoma, and now it’s as far west as Nevada.


The mussels clog up intake pipes at water and power plants and mess up
the food chain. In some places in the Great Lakes, they’ve severely
damaged the sport fishing industry.


And that’s the damage just one foreign pest can do. More than a
hundred have gotten in and more are on the way. The government has
done little to stop the spread of these pests from foreign ships. In
2005, a federal court in California ordered the EPA to set up a system.
The EPA appealed that ruling.


Andy Buchsbaum is the Director of the National Wildlife Federation’s
Great Lakes office. He says ballast water from foreign ships should be
regulated:


“The law is very clear. The Clean Water Act says you cannot discharge
pollution into navigable waters, like the Great Lakes, without first
obtaining a permit. Period. Any discharge without a permit
is illegal.”


So, instead of waiting for the EPA to act, several environmental and
conservation groups, including Buchsbaum’s group, say they are planning
to sue several shipping companies that operate ocean-going boats on the
Great Lakes. They’re targeting nine boats they feel are the biggest
violators.


Industry representatives have said that ballast water regulations would
hurt international shipping, but in the Great Lakes, it’s estimated
that ocean-going ships make up only 6% of the overall tonnage.


Joel Brammeier is with the Alliance for the Great Lakes, one of the
groups that intends to sue the ship owners. He says a few ocean-going
boats have caused a lot of damage:


“The cost savings that we’re seeing from allowing unregulated ocean
shipping on the Lakes pales compared to the economic burden that
invasive species are placing on the Lakes. That’s stunning. The
ocean-going shipping industry is actually bringing in less than the
region is losing because of the things that ocean going ships
unintentionally bring in.”


The environmental and conservation groups who intend to sue say there
are ballast water cleaning technologies available now. The National
Wildlife Federation’s Andy Buchsbaum says they’re willing to back off
their lawsuit if the ship owners promise to clean up their ballast
water:


“This legal action is not designed to shut down the shipping industry
in the Great Lakes. That is not our intention. Our intention is to
get these guys to comply with the Clean Water Act. And that means
putting on treatment technology and getting permits.”


The shipping industry says it needs more time. Steve Fisher is with
the American Great Lakes Ports Association. He concedes there are some
technologies to clean up ballast water:


“I’ll be very frank with you. There’s technologies out there that will
do something.”


(Brush:) “So, why not use those?”


“Because a ship owner needs to know how high the bar is before he jumps
over it.”


In other words the ship owners won’t clean up their ballast water until
the federal government tells them how clean is clean, and so far, the
federal government hasn’t done that.


The EPA and the shipping industry say they’re working on the decades
old problem, but the groups that intend to sue say they’re not moving
fast enough. More invasive species are getting in. They’re hoping the threat of a
lawsuit will help force more action sooner.


For the Environment Report, I’m Mark Brush.

Related Links

The Invasion of the Quaggas

  • A close-up of the quagga mussel. Quaggas have spread in all of the Great Lakes except Lake Superior. (Photo courtesy of the Michigan Sea Grant Archives)

Whitefish is a main dish for everything from fish boils to fancy dinners all around the Great Lakes region. But in some areas of the Great Lakes, whitefish aren’t doing so well. Rebecca Williams reports on what’s happening to the fish many people love to eat:

Transcript

Whitefish is a main dish for everything from fish boils to fancy dinners all around the Great Lakes region. But in some areas of the Great Lakes, whitefish aren’t doing so well. Rebecca Williams reports on what’s happening to the fish many people love to eat:

(sound of knives getting sharpened and fish being filleted)

Mike Monahan sells fish from all over the world at his seafood market. But he says whitefish is a very popular seller.


“It’s been there forever, and everybody just expects it to be there, and it’s inexpensive. But really it’s a great fish, as far as a nice light delicate fish, I’d put it up against the soles and flounders.”


Monahan says he’s still getting good supplies of whitefish. So, for now, he’s happy.


But some of the people who catch whitefish are worried. Commercial fishers have been hauling in skinnier whitefish in some parts of the lakes. It’s taking whitefish longer to grow to a size worth selling. And in some cases, the fish aren’t fat enough to make a good fillet.


(sound of shorebirds)


Paul Jensen fishes for whitefish in Lake Michigan. He says lately, he’s had to move his boat to deeper waters. That’s because whitefish are hungry and they’re swimming out deeper. They aren’t finding their favorite food. It’s a little shrimp-like creature called Diporeia.


“Diporeia are probably like a Snickers bar to whitefish; they were high in fats, high in lipids and it was their main food – it was very nutritious for them and it affected their growth rate. Eating Diporeia a fish could reach maturity maybe in 18 months or 2 years. Now we’re looking at fish that may take 5 years to get there.”


Whitefish are not eating Diporeia because it’s vanishing. In some places, researchers used to find 10-thousand of the little critters in a square meter of sediment. Now there are very few, or none at all.


Tom Nalepa has been trying to figure out why. Nalepa is a biologist with the National Oceanic and Atmospheric Administration’s Great Lakes Environmental Research Lab.


“It’s a real scientific puzzle as to why Diporeia is declining. It’s definitely related to the spread of quagga mussels and zebra mussels but that exact negative relationship is kind of elusive at this point in time.”


But Nalepa says he’s sure the invasive mussels are to blame. The mussels got into the Lakes in the ballast tanks of foreign ships. And they’ve spread in all the lakes except Superior.


Tom Nalepa says he’s seen populations of Diporeia crash right around the time the mussels were booming. Nalepa says now, Diporeia’s gone from large areas in most of the Lakes.


That’s bad because Diporeia is an important food source for most of the fish in the Great Lakes.


But for whitefish it’s really crucial. Back in the good old days, Diporeia made up about 80% of their diet.


Tom Nalepa says whitefish are trying to find something else to eat. He’s seeing them switch to a snack food that could make them even skinnier.


They’re starting to eat quagga mussels.


“When whitefish feed on quagga mussels they have to deal with the shell which has no energy content at all and it has to pass the shells through its digestive system so basically the fish feels full when it’s not getting any energy source.”


Nalepa says to the fish, quagga mussels must seem like good food, because there are lots of them.


He says quagga mussels are booming, because they can live in harsher conditions than zebra mussels can. So biologists are predicting quaggas will be even worse for the lakes than zebra mussels.


“Where are things ultimately going to end up? People may just have to get used to fewer fish. Because basically now we’re trading the fish community for the mussel community. The lakes are loaded with mussels instead of fish now. It may be just the way it’s gonna be.”


Some fishermen are already seeing things change. One day last season, Paul Jensen pulled in some of his nets. He was expecting fish.


“It was kind of startling because the amount of quagga mussels that came up with those nets far exceeded the catch of fish. And we hadn’t really equipped the boat with a snow shovel to shovel quagga mussels out of the boat. The impacts are startling because you begin to wonder, if our little net caught these, how many are there and what are the impacts going to be down the road?”


Jensen says he wishes the invaders had never gotten into the lakes in the first place, because there’s no way to predict what effect they’ll have next.


But some scientists worry these changes at the bottom of the food chain will lead to a major collapse of the fish stocks that many people depend on.


For the Environment Report, I’m Rebecca Williams.

Related Links

Multimillion Dollar Parasite Fight Continues

  • A sea lamprey, the first invasive species in the Great Lakes. (Photo courtesy of the USEPA)

One of the most destructive invasive species in the Great Lakes was also the first one to arrive. The sea lamprey invaded the Lakes more than a hundred years ago, and no one’s been able to get rid of it. As Rebecca Williams reports, it’s the only invader in the Lakes that managers have been able to control… but it takes millions of taxpayers’ dollars every year to keep the blood-sucking parasite in check, and there’s no end in sight:

Transcript

One of the most destructive invasive species in the Great Lakes was also the first one to arrive. The sea lamprey invaded the Lakes more than a hundred years ago, and no one’s been able to get rid of it. As Rebecca Williams reports, it’s the only invader in the Lakes that managers have been able to control… but it takes millions of taxpayers’ dollars every year to keep the blood-sucking parasite in check, and there’s no end in sight:

(Sounds of tank bubbling)


There’s a sea lamprey sucking on Marc Gaden’s hand.


“You can see he’s really got my thumb now, I’ll try and pull him off my thumb – this is a suction cup (popping sound of lamprey being detached).”


Gaden is with the Great Lakes Fishery Commission. It’s a group that was created by the US and Canadian governments with one main purpose: to control the sea lamprey. Gaden isn’t in any actual danger when a lamprey’s hanging on him. They don’t feed on warm-blooded creatures. But fish are another story.


“The mouth is ringed with sharp teeth, row after row of these sharp teeth, and in the middle of the mouth there is a tongue that flicks out and it’s sharp as a razor. What that tongue does is files its way through the side of the fish’s scales and skin and then the sea lamprey has access to blood and body fluids of the fish and that’s what it does, it feeds on them.”


Sea lamprey get fat drinking fish blood and fluids. They leave bloody holes in the side of fish, wounds that often kill the fish. Each lamprey can kill 40 pounds of fish a year.


Lamprey got into the lakes through manmade canals that connected to the Atlantic Ocean. By the 1940’s, the exotic species had invaded every one of the Great Lakes. Marc Gaden says by the 1950’s, lampreys had killed off most of the big predator fish in the Lakes.


“There’s literature around that time period that talked about gaping bloody wounds that commercial fishermen were finding on their catch, the commercial catch was beginning to go down the tubes, also because of overfishing, but sea lamprey was a major cause of that decline.”


Paul Jensen’s family used to fish for the popular lake trout before the lamprey wiped them out. Jensen now fishes for whitefish. He’s one of a small pool of commercial fishers who still pull a living from the Lakes.


“Every port along southern Michigan had commercial fishermen. South Haven, St. Joseph, Ludington, Manistee… There aren’t any, they’re gone. And one of the main reasons they’re gone, I think can be traced back to sea lamprey.”


Jensen says most commercial fishers these days have to do more than catch fish. He also runs a marina and builds research boats. Jensen says commercial fishers either had to adapt to the changes the lampreys brought or get out of the business.


“The whole food chain has just been devastated and turned upside down by exotics, and it’s been kind of a mystery; we have no clue as to where it’s gonna go. We’re glad with what we’re getting but I don’t know if we have much control of where it’s going.”


The people who manage fisheries have been wrestling for control over the sea lamprey. Marc Gaden says the lamprey control program has reduced the parasites’ numbers by 90 percent over the past 50 years. But he says lampreys have recently rebounded above target levels in several areas of the Great Lakes.


“It goes to show you these are crafty beasts. Even though they’re primitive and haven’t evolved much since the time of the dinosaurs, they still will find ways in which to spread and find new stream habitats and we always have to try our best to stay one step ahead of them.”


Gaden says the fishery commission has been aggressively treating the areas where lamprey numbers are too high. The main method is a lampricide that kills lamprey when they spawn in streams. Researchers are also working on chemical attractants to lure lampreys into traps.


But all of this takes money. Since the 1950’s, the US and Canada have spent about $300 million to keep lampreys in check. Marc Gaden says that sounds like a lot of money, until you look at the value of the fishery. It’s valued at about 4 billion dollars a year.


“So the amount of money we spend, upwards of 20 million a year, to keep lampreys under control, is a tiny fraction of the value of that fishery. But nevertheless it’s a cost we’re going to have to endure in perpetuity because the lampreys are not going away.”


But the Bush Administration’s proposed budget cut some of the funding for lamprey control. The fishery commission is hopeful that Congress will restore the funding. Marc Gaden says if we want any sport fishing, any tribal fishing, any commercial fishing… lampreys have to be kept under control, and that takes steady funding from Congress.


For the Environment Report, I’m Rebecca Williams.

Related Links

Multimillion Dollar Parasite Fight Continues (Spot)

The sea lamprey invaded the Great Lakes more than a hundred years ago, and no one’s been able to get rid of it. But Rebecca Williams reports it’s the only invader in the Lakes that managers have been able to control. Experts say it can only be kept in check if Congress continues to provide funding each year:

Transcript

The sea lamprey invaded the Great Lakes more than a hundred years ago, and no one’s been able to get rid of it. But Rebecca Williams reports it’s the only invader in the Lakes that managers have been able to control. Experts say it can only be kept in check if Congress continues to provide funding each year:


The sea lamprey got into the Great Lakes through a manmade canal. The parasite attaches itself to fish and sucks out the blood and body fluids.
By the 1950’s, sea lampreys knocked out the big predator fish in the Lakes.


A few years later, biologists discovered a pesticide that kills lampreys. That pesticide is the major tool managers still use today to keep lamprey numbers down.


Marc Gaden is with the Great Lakes Fishery Commission. The commission’s in charge of controlling the lampreys. He says in order to have healthy fish populations, lampreys have to be kept in check.


“It’s like a coiled spring, as long as you have your thumb on it, everything’s fine but the moment you take it away it’ll just spring out of control, bounce back right to where it was before.”


The Bush Administration’s proposed budget cut some of the funding for the lamprey program. But the fishery commission is hopeful Congress will restore the funding.


For the Environment Report, I’m Rebecca Williams.

Related Links

Invasives Destroying Great Lakes Food Chain

  • Biologists sorting fish. The populations of smaller fish that game fish eat have collapsed in Lake Huron. (Photo courtesy of MI DNR)

Although zebra mussels have been affecting the ecology of the Great Lakes since they were first found in 1988, researchers are continuously surprised at how much damage they’ve caused. Now, biologists are wondering if zebra mussels and the more recently arrived quagga mussels are to blame for a collapse of the fishery in one of North America’s largest lakes. Lester Graham reports the researchers are also wondering if this collapse is a preview of what will happen to all of the Great Lakes:

Transcript

Although zebra mussels have been affecting the ecology of the Great Lakes since they were first found in 1988, researchers are continuously surprised at how much damage they’ve caused. Now, biologists are wondering if zebra mussels and the more recently arrived quagga mussels are to blame for a collapse of the fishery in one of North America’s largest lakes. Lester Graham reports the researchers are also wondering if this collapse is a preview of what will happen to all of the Great Lakes:


It’s off-season for charter boat fishing and Captain Wayne Banicky asked if we could meet at a local watering hole called the Boat Bar. Captain Banicky takes people out fishing on Lake Huron. Well, he used to. The past few years he’s been charter boat fishing in Lake Michigan. He says fish started to become more scarce on Lake Huron, and he was forced to make the move.


“Economics, pure and simple. Dollars and cents. Once you start seeing a decline and being on the water every day and you see those declines in your numbers, it’s just a matter of time before financially you can’t afford to stay there. Those dock fees aren’t given up free. That’s an expensive tab to pay every year.”


Fishing for most species in Lake Huron is not good. But the story is not just a matter of not stocking enough fish or just a bad year, it’s a matter of a collapse of the bottom of the food chain. It’s not just the fish sport fishers like to catch that are down, it’s their prey: the smaller fish those big game fish eat. Prey fish stocks have collapsed, and supplies of the food those small prey fish eat, the plankton, have also collapsed.


Jim Johnson is with the Michigan Department of Natural Resources Alpena Fisheries Research Station.


“There was a huge decline in the amount of nutrients available to zooplankton and phytoplankton in the middle of Lake Huron. These are the basic nutrient bits that fish eat. And it appears now to most of us in the scientific community that a large portion of the nutrients that used enter Lake Huron are now being trapped by zebra and quagga mussels and not finding their way to alewives and other prey fish.”


Scientists from different government agencies and universities in the U.S. and Canada had been noticing changes, but things have gone seriously wrong very quickly in Lake Huron, and it might go wrong other places.


Tom Nalepa is with the National Oceanic and Atmospheric Administration’s Great Lakes Environmental Research Lab. He says tiny aquatic food sources for fish, such as a shrimp-like organism called diporeia, are declining dramatically in other Great Lakes.


“All the players are in place for it to happen in these other lakes too, you know, the loss of diporeia, the expansion of quagga mussels. And maybe Lake Huron is the first to show a collapse in the prey fish. What does it mean? Well basically, you know, there’s not going to be many fish out there for the sport fisherman to catch anymore.”


And sport fishing is multi-billion dollar industry in the Great Lakes. Back at the Boat Bar, charter fishing boat captain Wayne Banicky says fishing is still good in Lake Michigan, but he worries when he thinks about what happened in Lake Huron.


“I think that the fishery as a whole in the Great Lakes is in serious jeopardy right now. Something’s got to be done.”


But the question is what? What can be done when invasive species are changing an entire ecosystem to the point the fishery collapses?


“I don’t know to be honest with you. I don’t think any one of us knows. It’s scary, that much I will admit to you. It is scary right now.”


And guys like Captain Banicky aren’t the only ones worried.


Jim Johnson at Alpena Fisheries Research Station says you can’t undo the damage that’s already done. It’s just a matter of waiting to see how nature responds to the invasive zebra and quagga mussels and other invaders. Johnson says the key is to prevent more invasive species from being introduced to the lakes.


“The best we can do right now, I think the single most effective thing we as managers can do, is to make it understood by the decision makers just how disruptive the invasive species are and try to put a stop to those.”


The source of many of these invasive species is the ballast tanks of foreign ships entering the Great Lakes. Some regulations have reduced the chance that more invasive species will hitchhike to the Great Lakes, but more are still getting in. In the meantime, agencies such as the US Environmental Protection Agency and the US Coast Guard say Congress hasn’t given them the authority to regulate foreign ships strictly enough to stop new invasive species from entering.


So, fishery managers can only watch the other Great Lakes for more signs of a collapse of the fisheries as they’ve only been able to stand by and watch happen in Lake Huron.


For the Environment Report, this is Lester Graham.

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Ten Threats: Mercury and Health Problems

  • Fish advisories warn about possible mercury contamination, but many people aren't aware of the risks. (Photo by Lester Graham)

There’s no disputing that fish is healthful food, but too much of certain
kinds of fish can be dangerous, especially if you’re a woman planning to
have children. That’s because some fish contain elevated levels of
mercury. Mercury is a toxic contaminant that can cause neurological
damage. Julie Halpert filed this report about the harms mercury can
cause:

Transcript

We’re continuing our series ‘Ten Threats to the Great Lakes.’ One of the
threats identified by experts was air pollution that in turn pollutes the
lakes. The Great Lakes Radio Consortium’s Lester Graham is our guide
in this series. He says the next report looks at one pollutant that
eventually affects people.


There’s no disputing that fish is healthful food, but too much of certain
kinds of fish can be dangerous, especially if you’re a woman planning to
have children. That’s because some fish contain elevated levels of
mercury. Mercury is a toxic contaminant that can cause neurological
damage. Julie Halpert filed this report about the harms mercury can
cause:


Three years ago, when she was 18, Ayla Brown was healthy, but
suddenly, she started getting sick all the time. She was always tired, she
became anemic and had sore throats. Her tonsils had deteriorated so
much that they had to be removed. Her doctor couldn’t figure out why,
so he decided to test her for heavy metals poisoning.


The result? Ayla’s mercury levels were off the charts. They were five
times higher than the normal level. Her entire family was tested and
their levels also were above normal.


“The only conclusion we could come to is that in the past year or so since
we had moved to Ann Arbor, we had started eating a lot of fish and a lot
of fish that we now know is very known to be high in mercury, such as
swordfish and tuna and stuff like that.”


The Browns ate several meals of fish every week. Some of it was
ocean fish. Some of it was Great Lakes fish. After the diagnosis, they
cut fish out of their diet altogether. Within a year, the mercury levels
returned to normal.


“You are trying so hard to eat healthy and my family always was very
health conscious and so it’s so frustrating when you’ve done something
that you thought was good for you and realize that it was completely the
wrong thing.”


Fish are generally considered part of a healthy diet, but not all fish are
entirely safe. That’s because of mercury. Mercury exists naturally in the
environment at low levels, but higher amounts are getting into the food
chain.


Coal-burning power plants emit mercury, which eventually settles into
the Great Lakes. Then, aquatic microorganisms convert the substance
into methyl mercury, which is more toxic.


Those microorganisms form the base of the food chain. Small fish eat
microorganisms. Then, larger fish eat the smaller ones. As that happens,
the mercury concentrations escalate, making big large mouth fish like
trout, salmon and some walleye especially contaminated.


When people eat the fish, the mercury is passed on to them. Women of
childbearing age and their fetuses are most at risk.


Michael Carvan is with the University of Wisconsin-Milwaukee’s Great
Lakes Water Institute. He says the exposure isn’t just from the fish that
women eat while they’re pregnant. A woman can pass her entire lifetime
load of mercury to her baby. He says that 15% of all women of
childbearing age have high enough levels so that their fetuses will
contain mercury of one part per million or higher.


“Even at really low levels, around one part per million, you’re talking
about some subtle coordination difficulties, you’re talking about
problems with memory and problems with neuro-processing and IQ
deficits.”


Because of these concerns, the Environmental Protection Agency and
the Food and Drug Administration issued an advisory for women of
childbearing age and children, suggesting they eat fish and shellfish only
twice a week.


But one expert is concerned by all this talk about how mercury harms
people. John Dellinger was on a task force, which provided guidance on
fish consumption advisories. Dellinger studied people who lived on
Lake Superior who he thought would eat a lot of fish, but he found
something else.


“We basically discovered that from an epidemiologic point of view, these
populations have other things that are adversely affecting their health,
that in fact will probably overshadow anything we’re going to see from
the contaminants in their fish.”


Dellinger said the people were so concerned about contaminants in
fish, that they started relying on store-bought, processed food instead.
Those foods were higher in fat and sugar and contained other, less
healthful, ingredients. So, obesity and diabetes caused health problems,
not mercury poisoning, and Dellinger says that ended up being a worse
situation.


He says the key is to choose wisely, avoiding fish such as swordfish,
tuna steaks and the larger predator Great Lakes fish that are high in
mercury. That’s the only measure you can take right now, but that doesn’t
solve the problem. The real challenge will be to get rid of the mercury
that ends up contaminating the fish.


For the GLRC, I’m Julie Halpert.

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.

Related Links