Tag: great lakes water institute

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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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

Assigning Blame for Beach Closings

More communities along the Great Lakes are testing their beaches and fighting over who’s to blame for beach closings. One dispute along Lake Michigan involves the performance of a multi-billion dollar sewage system in Milwaukee. The Great Lakes Radio Consortium’s Chuck Quirmbach reports:

Transcript

More communities along the Great Lakes are testing their beaches and fighting over who’s to blame for beach closings. One dispute along Lake Michigan involves the performance of a multi-billion dollar sewage system in Milwaukee. The Great Lakes Radio Consortium’s Chuck Quirmbach reports:


Some Illinois Congress people have asked the EPA to stop Milwaukee from dumping sewage into Lake Michigan. The politicians say a major sewage tunnel installed in Milwaukee a decade ago still allows too much untreated material into the water. They argue that city sewage is to blame for a sizable increase in Illinois beach closings over the last few years. But Val Klump of the Great Lakes Water Institute at the University of Wisconsin-Milwaukee says the local sewer tunnel has greatly reduced the number of sewer overflows.


“Now that’s not to say we’re content with allowing any kind of untreated material getting into our waterways. That’s not our goal.”


But Klump says given other factors like dilution and other bacterial sources like gull droppings and pet waste, it’s less likely that Milwaukee wastewater is fouling beaches fifty miles south.


For the Great Lakes Radio Consortium, I’m Chuck Quirmbach in Milwaukee.