Tag: university of minnesota

Killing the Common Carp

  • The Common Carp was introduced a century ago and has been causing havoc in rivers, ponds and lakes ever since. (Image by Duane Raver, courtesy of the U.S. Fish and Wildlife Service)

In thousands of lakes and ponds across the country, there’s a fish messing up the water.
Some biologists say we’ve never seen these lakes the way nature intended due to the
common carp. The usual method to get rid of the common carp is to kill everything in
the lake and start over. Some biologists think there’s got to be a better way. Joel
Grostephan reports:

Transcript

In thousands of lakes and ponds across the country, there’s a fish messing up the water.
Some biologists say we’ve never seen these lakes the way nature intended due to the common carp. The usual method to get rid of the common carp is to kill everything in
the lake and start over. Some biologists think there’s got to be a better way. Joel
Grostephan reports:


Common carp are like underwater pigs. They root up aquatic plants. They constantly stir
up the mud in the bottoms of lakes, making them murky. And in some lakes, common
carp make up more than half of the total weight of fish. Peter Sorensen is a fisheries
professor at the University of Minnesota:


“With their habit of rooting around night and day, they will completely destroy the
bottoms of lakes, so they become cesspools.”


And it ruins the habitat for many birds and fish too:


“The fact is they are doing enormous damage. At a level that I don’t think people
fully realize. They are living with us, and we don’t know in many cases, what
these lakes and streams and rivers should be like and could be like.”


Common carp have been in U.S. lakes and ponds for more than a century. They came
from Europe and Asia. At the request of new immigrants, the United States government
stocked carp in lakes and rivers in the late 1800’s. Sorensen says it didn’t take long before
there were problems.


By the early 1900’s, it clicked this was a huge mistake, and they started to remove
them. Good records were not kept, and Sorensen says the overall impression is that
removal efforts didn’t work. Most attempts to control the fish are still unreliable. The fish
is very tough. It spawns every year, and females produce nearly a million eggs.


Fisheries managers try to control carp the best they know how. Some hire commercial
fisherman to net the carp. They also use poison — killing all the carp and all the other
fish in the lake and then start over.


Fisheries managers currently use a chemical called Rotenone, which they say is not toxic
to humans. Lee Sundmark is with the Minnesota Department of Natural Resources:


“If we see that a lake that a lake way out of balance, might have a lot of carp,
bullheads, tried biological means, and they aren’t working. Sometimes we get to the
point where we use Rotenone to treat it. We basically clean a lake out, and then we
might restock it.”


The trouble is sometimes not all the carp die. And just a handful of them can reproduce
and dominate that lake within a few years. Peter Sorensen and his team of researchers
believe there’s a better way. Sorenson says he does not object to Rotenone poisoning out-
of-hand but, he says, it’s expensive, heavy handed. He and his team have been studying
carp-infested lakes for the past three years to see if they can come up with a new method
to control the fish.


On this cold day, the biologists are surgically implanting radio tags in carp. The
scientists will be tracking these fish so they can find weak points in their lifecycle.
Prezmyslaw Bajer and his colleague Mario Traveline are about to operate on a fish they
caught:


“She will be collecting data that we will then use to remove carp from the lake. She
will be our carp spy.”


The researchers say if they can figure out the habits, and the instincts of the Common
Carp, they will able to control them in way that’s both — effective, and doesn’t kill all the
other fish in the lake. The study’s lead investigator, Sorensen, says this is important
work:


“Something must be done. This is our first, and most damaging species, and if we
don’t do something with this, that like I said, we can do something about — I wonder
what hope there is for any of them. This is to me, the one you got to take out.”


Sorensen says he hopes he can create a model that can be replicated in different parts of
the country. If he’s successful, the ponds, lakes and rivers that have been assaulted by the
carp for the last century might once again be able to host fish and other wildlife that were
forced out.


For the Environment Report, I’m Joel Grostephan.

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Beautiful Drafty Old Houses

  • Historic homes like James Boyd Brent's pictured above are beautiful, but not very energy efficient. (Photo by Diane Richard)

People who choose to live in historic houses tend to appreciate old-world
charm. But that charm often comes at the expense of energy efficiency.
Old windows and doors let in cold drafts and leak out warm air. So
homeowners are often forced to balance their interests in historical
integrity and aesthetics against their environmental principles:

Transcript

People who choose to live in historic houses tend to appreciate old-world
charm. But that charm often comes at the expense of energy efficiency.
Old windows and doors let in cold drafts and leak out warm air. So
homeowners are often forced to balance their interests in historical
integrity and aesthetics against their environmental principles:


My neighbor James Boyd Brent had me over to his house the other day.
He lives in a beautiful old farmhouse that’s about 130 years old. It’s got tall
ceilings. Rickety staircases. Original windows, floors and doors. But what
makes it cool also makes it cold. Really cold.


James recently had an energy audit done. Today he’s showing me all the
problems he needs to fix. He greets at the door me wearing a knit hat. And, even
though he’s lanky, he looks a bit padded.


“Well, I’ve got a vest, like a t-shirt, a shirt – a very thick shirt, actually –
then a sweater and another sweater. So that’s just four layers.”


That’s because it’s really cold inside. James is a Professor of Design at the University of Minnesota. He has a
taste for beautiful old things. But that puts him in a bind. Does he sacrifice
what he loves about his old home to improve his green cred? Or does he
simply live with the howling gales blowing down his hallways?


It’s a dilemma he confronts every winter. Preserving aesthetics versus
conserving energy. He says it’s not a strict either-or. And he’s willing to
install modern conveniences when it makes sense:


“I’m not interested in being faithful to some sort of bourgeois idea about what
history is.”


To prove it, he shows me the ultra-high-efficiency furnace and water
heater he recently installed in his basement. But I notice something else
down here:


Richard: “I see light coming through there.”


Brent: “Yeah. Exactly. That’s daylight. There’s not even a window. There’s
nothing. There’s just a hole.”


Upstairs, it’s bad enough. James’s house rarely tops 60 degrees. Down
here though, I can see my breath:


“Last year it froze down here. Rollicks’s cat water froze solid. I saw her
once sort of tapping it with her paw with a look of irritation.”


We leave the basement and its gaping hole for another day. Today’s chores start in the
kitchen:


“Okay, first of all, I’m working on this door here. Actually, as you can see, I’ve
sealed this all around in layers, actually. But I’ve just decided it’s not
enough. It’s still letting in great currents of cold air coming through. So I’m
going to actually seal the whole thing, right on the outside here. I’m just
sticking that down here a bit more strongly on the bottom. Because actually, that’s where
the cold air is coming through.”


The energy audit helped James figure out where he was losing the most
heat. Windows, doors, baseboards, walls and attic all were culprits:


“The basic thing is, that’s what came out of the energy audit. That all of
this sort of stuff that I’m doing now is basically, um, the sign of a complete
loser.”


Richard: “What do you mean?”


Brent: “Well, in the sense that it’s taking up all of my time and I might as well live
in a shack.”


James is not alone. Lots of people are in the same fix, loving their
beautiful home, hating that it’s as drafty as a barn.


I talked to Paul Morin about James’s frustration. Paul is a home energy
expert. He says the taping sheets of plastic over old doors and windows
should pay off:


“That really reduces the amount of air infiltration and also adds another
insulating layer. So that’s very effective.”


Paul says there’s lots more James can do, but taping up things is cheap and easy. Now, James is not looking forward to pulling down all the film next spring. But
he’s willing to keep doing it, because it’s the only way he can
balance his appreciation for the past and his commitment to the future:


“I mean, obviously I could heat this house just by cranking up the furnace and
not worrying. But it would cost literally thousands of dollars a quarter.
And also it’s just a complete waste of energy. I do have a sort of sense of
the connection between wasting money, and also wasting energy, wasting resources
and being wasteful.”


So, like a lot of people who love their old homes, James’ weekends will
be spent sealing up his house. It’s that or spend a lot of
money on expensive upgrades, or wasting money on heat that escapes
through the drafty windows and doors. And that big hole in the
basement.


For the Environment Report, I’m Diane Richard.

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Ethanol Puts Strain on Immigrant Farming

  • Jenny Chang at a farmers' market with her produce. (Photo by Joel Grostephan)

Demand for corn-based ethanol is growing and that’s made farmland more valuable. This
year, American farmers planted 14 million acres more corn than they did last year. Some
small immigrant farmers believe that’s why they’re having a hard time finding land to rent
to grow fresh fruits and vegetables. Joel Grostephan reports:

Transcript

Demand for corn-based ethanol is growing and that’s made farmland more valuable. This
year, American farmers planted 14 million acres more corn than they did last year. Some
small immigrant farmers believe that’s why they’re having a hard time finding land to rent
to grow fresh fruits and vegetables. Joel Grostephan reports:


Jenny Chang doesn’t want to change the government’s policy on ethanol subsidies. She
just wants some good land to raise her vegetables that she sells at the farmer’s market.
When planting time came around this year, she was still looking for a plot to rent. Chang is
Hmong and she came from Laos more than 20 years ago with few job skills. For
the last 7 years, she’s made part of her income from farming on land she rents. In the
past, finding land to rent wasn’t that hard. But, Chang says through her daughter who
interprets for her, this year was different:


“She said that this year, we couldn’t find land, that’s why we got stuck with this bad area.
She’s really sad.”


With corn selling for double what it did last year, land values are going up. That means
rent is going up. And the 300 Hmong farmers in this area are having a hard time finding
land they can afford.


Kent Olson is an economics professor at the University of Minnesota. He says he thinks
land scarcity is due to higher demand for ethanol:


“Your ethanol may have started the ball rolling, and created higher prices for corn, which
pushed corn onto other land from other crops but that’s pushed soybean prices up. So we
are seeing higher rent from a couple different directions.”


In theory, ethanol from corn is supposed to be good for the environment. It burns cleaner
and means less reliance on foreign oil.


But… conventional corn farmers rely on fossil fuel-based fertilizers and chemical
pesticides. By the time their diesel-powered tractors plant the corn, combines harvest it,
trucks transport it and ethanol distillery plants cook it, the energy gain from corn ethanol
is marginal.


The Hmong farm differently. Most don’t use fossil fuel-based fertilizers or pesticides.
Instead, they do a lot of hand weeding, and put in long days. Jenny Chang fertilizes her
tomatoes with chicken manure. Chang’s daughter, who is also named Jenny Chang, says
many older Hmong farmers are suspicious of chemicals:


“They like gardening the way they used to back in old Laos. They don’t really know what
insecticides and pesticides are, or how to use it so that’s why they just don’t use it. And a lot of
people are afraid of cancer, so they just like to grow things organically because they eat it
themselves.”


And researchers say growing food this way seems more environmentally friendly than
growing corn for ethanol.


Bill Moseley is a professor at Macalester College in St. Paul. He studies the
environmental effects of agriculture:


“Conventional corn production is displacing, in this particular case, a form of
agriculture that is more environmentally sound in terms of it’s using fewer fossil
fuel imports, and it’s producing crops for the local market, it’s particularly ironic in
this instance.”


Government officials don’t think increased corn production for ethanol is the problem.
Perry Aasness works with the U.S. Department of Agriculture’s Farm Service Agency. When he learned the Hmong farmers were having a hard time finding land to rent, his
agency helped them. But Aasness believes corn production for ethanol is NOT the cause
of the land shortage:


“Well, at least in Minnesota I think it’s very, very minimal. I think the real issue that I
have seen in Minnesota is that the Hmong farmers, the Hmong community is primarily
based in the Twin Cities metro area. They have to go further out to get land — a lot
of it I think is just due to urban sprawl.”


For many people in the Minneapolis-St. Paul area, the Hmong are the face of agriculture
at farmers markets. But since no government agency keeps track of their numbers, it’s
hard to know if their tradition of raising crops on small plots of rented land is going well,
or if ethanol and high corn prices are actually putting their small businesses in danger of.


For the Environment report, I’m Joel Grostephan.

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Nanotech Nervousness

  • Researchers are studying whether nano-sized material could purge bacteria from the digestive tracts of poultry. The bacteria doesn't harm chickens and turkeys, but it can make people sick. The hope is that using nanoparticles could reduce the use of antibiotics in poultry. (Photo courtesy of USDA)

Nanotechnology is the science of the very, very small. Scientists are
finding ways to shrink materials down to the scale of atoms. These
tiny particles show a lot of promise for better medicines, faster
computers and safer food. But Rebecca Williams reports some people are
worried about harmful effects nano-size particles might have on
people’s health and the environment:

Transcript

Nanotechnology is the science of the very, very small. Scientists are
finding ways to shrink materials down to the scale of atoms. These
tiny particles show a lot of promise for better medicines, faster
computers and safer food. But Rebecca Williams reports some people are
worried about harmful effects nano-size particles might have on
people’s health and the environment:


Life on the nano scale is so tiny it’s hard to imagine. It’s as small
as 1/100,000 of a human hair. It’s as tiny as the width of a strand of
DNA. A nanoparticle can be so small it can actually enter cells.


Nanoparticles are loved by scientists and entrepreneurs for the novel
things they can do at those tiny sizes. They act differently. They
can go where larger particles can’t.


Many companies already sell new products with nano properties. The
Project on Emerging Nanotechnologies says there are almost 500 products
on the market that use nanotechnology.


Some of those products are starting to show up in the grocery store.


Jennifer Kuzma is with the Center for Science, Technology and Public
Policy at the University of Minnesota. She tracks nanotech
developments in food and agriculture. She says there are some edible
nano products on store shelves right now:


“One is a chocolate shake that is a nano emulsion of cocoa molecules so
you can deliver more flavor for less of the cocoa product.”


Kuzma says that’s just the beginning. She says hundreds more nano
products, including a lot of food products, are on their way to market.
In many cases, scientists are looking for solutions to food safety
problems.


For example, bacteria in the intestines of chickens and turkeys can
make people sick when poultry is undercooked. Right now farmers treat
their birds with antibiotics. But as bacteria are becoming resistant
to antibiotics, scientists are looking for other methods to fight the
bacteria.


Jeremy Tzeng is a research scientist at Clemson University. He’s part
of a team developing what he calls intelligent chicken feed.
Basically, chickens would be fed a nanomaterial that attaches to
molecules on the surface of the harmful bacteria. Then the bacteria
could be purged from the chicken along with fecal matter:


“If we use this physical purging, physical removal, we are not using
antibiotics so the chance of the microorganism becoming resistant to it
is really small.”


Tzeng says his research is still in its early stages. He says there
are a lot of safety tests he needs to run. They need to find out if
the nanomaterial is safe for chickens, and people who eat the chickens.
And they need to find out what happens if the nanomaterial is released
into wastewater.


“As a scientist I love to see my technology being used broadly and very
quickly being adopted. But I’m also concerned we must be cautious. I
don’t want to create a miracle drug and then later it becomes a problem
for the long term.”


There are big, open questions about just how safe nanoparticles are.


Researcher Jennifer Kuzma says there have been only a handful of known
toxicology studies done so far. She says nanoparticles might be more
reactive in the human body than larger particles:


“There’s several groups looking at the ability of nanoparticles to
damage, let’s say your lung tissue. Some of the manufactured or manmade nanoparticles are thought to have greater abilities to get into the
lungs, penetrate deeper and perhaps damage the cells in the lungs, in
the lung tissue.”


In some cases, it’s hard for the government to get information about new
nano products. Kuzma says companies tend to keep their own safety data
under lock and key:


“Some companies might send you the safety studies if you ask for them. Others may not
because they of course have interests in patenting the technology and
confidential business information.”


So the government doesn’t always know all that much about what’s
heading to market. Agencies are trying to figure out how – and even
whether – to regulate products of nanotechnology. Right now, there are
no special labeling requirements for nano products.


In the meantime, nanotechnology is turning into big business. Several
analysts predict that just three years from now, the nanotech food
market will be a 20 billion dollar industry.


For the Environment Report, I’m Rebecca Williams.

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Part 1: Carmakers Push for More Ethanol

  • Switchgrass is an easily grown biofuel crop, which can be used to make ethanol. (Photo courtesy of the National Renewable Energy Laboratory)

This summer, drivers got a crash course in the dangers of fossil fuel. Gas prices shot above three dollars a gallon, concerns about global warming surged, and instability continued to plague areas of the world where oil is produced. We’ll be taking a look at some of the technologies that could help the US kick its fossil fuel habit. We’re starting with an alternative fuel that’s been sprouting up in gas stations across the region. Dustin Dwyer has this look at the promise, and the limitations of ethanol:

Transcript

This summer, drivers got a crash course in the dangers of fossil fuel. Gas prices shot above $3 a gallon, concerns about global warming surged, and instability continued to plague areas of the world where oil is produced. We’ll be taking a look at some of the technologies that could help the US kick its fossil fuel habit. We’re starting with an alternative fuel that’s been sprouting up in gas stations across the region. Dustin Dwyer has this look at the promise, and the limitations of ethanol:


This summer, Misty Childs found a way to do something positive about the fossil fuel problem. She says that she and her husband realized their Chevy Silverado pickup could run on E-85, a blend of 85 percent corn-based ethanol and 15 percent gasoline.


E85 burns cleaner than gas alone, so it’s good for the environment. And the ethanol is made from corn grown in the US. As she tops off her tank at a gas station, Childs says that makes a difference.


“It means a lot that we’re doing something for our country here, and not having to rely on others.”


Detroit’s Big Three automakers have been making a big push for E-85 in the last year. E-85-capable vehicles get the automakers a credit on federal fuel economy standards. So, even if drivers put regular gas in the vehicles instead of E-85, Detroit still gets a credit for doing better. And this summer, as more buyers became aware of the problem with fossil fuels, E-85 was just about the only alternative Detroit had to offer.


But ethanol as it’s currently made has limits. Jason Hill is a researcher at the University of Minnesota. He recently published a study on the long term outlook for corn-based ethanol.


“What we found is if you convert every corn kernel we produce in this nation to ethanol, we would be able to offset only about 12 percent of our national gasoline usage. So that’s not that large.”


That’s every corn kernel, including what we currently use for food. Which brings up another problem with ethanol: if E85 jumps in popularity, will that mean less corn for animal feed and grocery stores?


Maybe. Corn originally became popular because it was already being grown around much of the country, with help from federal subsidies. And ethanol processors, such as Archer Daniels Midland, also got tax breaks for making corn-based fuel.


But there’s another option for ethanol. Inside a lab at Michigan State University, researchers are working on the next generation of the fuel. This is what’s called cellulosic ethanol. Instead of using grains like corn kernels, cellulosic ethanol is made from the starches in plant cell walls. It can be made from pretty much anything that stands up straight – wood, prairie grasses and corn stalks.


That offers the possibility to increase the ethanol output for every acre of land devoted to the crops, and those crops don’t require fossil fuel-based fertilizer. They also don’t require planting every year by gas or diesel burning tractors the way corn does.


Professor Bruce Dale heads research into cellulosic ethanol at MSU. He says the current problem with cellulosic ethanol is finding a cheap way to break down the stiff materials. His lab uses ammonia to do the trick.


“The idea is to make cheap sugar. And the plant cell walls potentially could give you the cheapest sugar on the planet, if we could figure out how to get at that sugar easily. That’s what our ammonia process does in combination with the enzymes.”


It turns out that, much like a teenager eating pop-rocks, cars and trucks get a whole lot of energy from fuels based on sugar. Dale says most woody plants have plenty of sugar, but it’s really hard to get that sugar out.


Dale says some cellulosic ethanol could be on the market in the next few years, and the fuel could eventually sell for about 60 cents a gallon.


Right now, ethanol is still hard to find at the pumps. And one study says, even with major investment over the next decade, cellulosic ethanol might only equal half of our current oil useage by 2050.


That’s still a lot. But to really eliminate the need for gas, many experts say it’ll take more than just one technology.


For the Environment Report, I’m Dustin Dwyer.

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Wetlands to Slow or Grow Global Warming?

  • John Pastor is trying to figure out how climate change will affect bogs and fens like this one. (Photo by Bob Kelleher)

In northern Minnesota, a researcher says wetlands like bogs could be key to how fast the climate changes worldwide. And the areas like the upper United States and Canada in the bull’s eye for rapidly changing temperatures and rainfall. The GLRC’s Bob Kelleher reports:

Transcript

In northern Minnesota, a researcher says wetlands like bogs could be key to how fast the
climate changes worldwide. And the areas like the upper United States and Canada in the
bull’s eye for rapidly changing temperatures and rainfall. The GLRC’s Bob Kelleher
has more:


What have wetlands, like fens and bogs, got to do with global warming? John Pastor says,
plenty.


Pastor is a professor and researcher with the Natural Resources Research Institute of the
University of Minnesota-Duluth. When Pastor straps on his hip waders, he goes where
almost no one else dares to go: into northern Minnesota’s fens, where water can be
several feet deep, and onto the bogs, where the mass of plant material is so thick it floats
on standing water.


A seven year-long study has revealed that fens and bogs can either help slow global
warming, or accelerate it. Pastor says all cards are off the table if temperatures keep
rising:


“The one problem in science that has the most ramifications throughout all of science – it’s
global warming.”


We’re in a swamp north of Duluth, Minnesota. Actually, it’s a fen, and it borders some
higher landscape nearby that’s a bog. What fens and bogs have in common is water and
peat, the not quite decomposed stuff left over when plants die. Pastor says peat lands are
one of the world’s significant bank accounts for carbon. They keep carbon out of the
atmosphere.


“Peat lands cover only 3% of the earth’s surface, but they contain 30% of all the carbon
that’s in all the soil in the world, locked in that partially decomposed organic matter, that
peat.”


Minnesota has vast peat lands that have been storing carbon for 10,000 years, but even
the size of Minnesota’s peat lands pales compared to those further north – around
Canada’s Hudson Bay, or in the Russian republics – all regions Pastor says that are facing
higher temperatures.


“All of the global climate models, one thing they all agree on, is that the greatest amount
of warming will occur in areas from Minnesota northward, and then inland – mid-
continent areas. So here we are. We’re sitting right now, right in the bullseye of the
greatest amount of warming that will happen on the face of the earth.”


This is the question: Will higher temperatures help trap more carbon in bogs, or force
more carbon into the atmosphere?


In this bog, Pastor’s been trying to figure out how warmer weather will affect bogs and
fens, and, in turn, what role the wetlands will play in global change. One thing he’s
found: the results depend largely on the water table, and that’s going to depend on
rainfall.


In some combinations, say with additional heat and additional rainfall, bogs could thrive,
trapping more carbon. That would be good. In other conditions, say with more heat but
less rainfall, bogs and fens could die and decompose, releasing even more carbon into the
atmosphere. That, Pastor says, would be bad:


“Now we have kind of a double whammy. Not only are we putting carbon dioxide from
fossil fuel into the atmosphere, the warning from that could cause the carbon from the
peat land also to go into the atmosphere and accelerate the warming.”


Predicting an outcome becomes mind numbing. Pastor’s working with new mathematical
theory to try to determine at what point global warming has gone too far.


“And so what seems to be happening is the temperatures of the earth have crossed some
kind of a threshold, where all the sudden, before that they crossed that threshold, the old
earth that we grew up with was stable. Now, it’s becoming very unstable, and ice sheets
are collapsing, birds and plants are migrating – everything’s happening very, very
quickly. And we’re going to enter into a new kind of earth that has a different kind of
stability – a different stable endpoint.”


Pastor says there’s no more complicated problem in all of science than global warming,
and no more important problem. Global warming, he says, changes everything, from the
forests to the wetlands. Pastor’s hoping the new mathematical models will provide more
definitive answers in time to do something about the outcome.


For the GLRC, I’m Bob Kelleher.

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Study Finds Ethanol Not Efficient Enough

The ag industry, some politicians and now automakers
are pushing the idea that ethanol made from corn will help reduce reliance on foreign oil. But another study further indicates that
corn ethanol is not the best solution. The GLRC’s Lester
Graham reports:

Transcript

The ag industry, some politicians and now automakers are pushing the idea that ethanol
made from corn will help reduce reliance on foreign oil. But, another study further
indicates that corn ethanol is not the best solution. The GLRC’s Lester Graham reports:


Despite the huge push for corn ethanol, a new study adds to the growing body of
evidence that indicates ethanol from corn is not a viable answer to replace gasoline. New
research from the University of Minnesota has been published by the Proceedings of
the National Academy of Sciences. It shows that ethanol from corn only yields 25
percent more energy than it takes to produce it.


The study also found greenhouse gas emissions and air pollution improvements were
only slight using corn ethanol, a bit better using soy diesel. But, the researchers say even dedicating all U.S. corn and soybean production to bio-fuels instead of food would only
meet 12 percent of the demand for gasoline and six percent of the demand for diesel.


The researchers conclude that other more woody plants and wood by-products could
provide much greater supplies and environmental benefits than food-based bio-fuels.


For the GLRC, this is Lester Graham.

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Ten Threats: Luring the Lamprey

  • The sea lamprey, up close. (Photo courtesy of USFWS)

One of the Ten Threats to the Great Lakes is the decline of many of the native species. The lake trout has been in trouble from over-fishing and because of an invasive species called, the sea lamprey. Conservation agents use a pesticide to keep the lamprey down, but it’s expensive, and sometimes it kills other fish. Now, researchers have discovered a lamprey pheromone that could help the fight against the sea lamprey. Stephanie Hemphill has that story:

Transcript

In our next report in the series Ten Threats to the Great Lakes we hear about how a native
fish has been hurt by an invasive species that swam into the lakes through a canal. Lester
Graham is our guide through the series.


One of the Ten Threats to the Great Lakes is the decline of many of the native species.
The lake trout has been in trouble from over-fishing and because of an invasive species
called, the sea lamprey. Ever since it invaded the Great Lakes, scientists have been trying
to keep the invasive sea lamprey under control.


Conservation agents use a pesticide to keep the lamprey numbers down, but it’s expensive,
and sometimes it kills other fish. Now, researchers have discovered a lamprey
pheromone. They think the chemical attractant could be a big help in their fight against
one of the most destructive invasive species in the Great Lakes. Stephanie Hemphill
has that story:


The sea lamprey came into the Great Lakes through canals more than a hundred years
ago. The slimy parasites attach themselves to big fish and feed on them until they die.
Each lamprey can kill 40 pounds of fish in its lifetime.


Between sea lampreys and over-fishing, the big native fish, the Lake Trout, was wiped out
in the lower Great Lakes. Only a few survived in small pockets in Lake Huron. Lake
Superior is the only place Lake Trout survive in healthy numbers.


There’s an aggressive 15-million dollar a year program to keep sea lamprey numbers
down. Part of the effort is using a chemical called TFM that kills the lamprey.
Wildlife managers spread the lampricide in streams in the spring. It kills some of the
young lamprey as they swim down into the lake.


University of Minnesota biologist Peter Sorensen says he and other scientists noticed that
TFM kills not just the juveniles, but the larvae that live in the streambed too. They also
realized, after a stream is treated, very few adult lamprey come back to the stream to
spawn, or lay new eggs.


“And this led to an observation decades ago, which was key, that adult lamprey must be
selective in how they pick streams. They only pick a few, and if you remove the larvae
they don’t seem to go in there.”


Scientists suspected the larvae might play a role in the spawning migration of adults.
That might mean the larvae are putting out a pheromone that tells the adults it’s a good
place to spawn. Just one larva attracts a lot of adult lamprey, indicating the pheromone
is very potent.


It was up to Jared Fine to determine what the chemical is. Fine is a PhD student working
with Peter Sorensen. For two years he sifted through the water in tanks holding lamprey
larvae.


“Separating the different chemical compounds, testing them biologically, seeing which
ones have activity, coming back to the active ones, further separating them, and just
repeating this until you get down to the one or two or three compounds that have the
activity.”


Fine narrowed it down to three compounds. He purified them and gave them to a colleague in the chemistry department, Thomas Hoye. Hoye created a synthetic version of the most potent pheromone. He says it should be possible to produce it on a large scale, and that means it could be used to treat the
Great Lakes. The question is, how much would he need?


“You know, would it be a tank car load, would it be a football field, would it be a dump
truck? It’s none of those. Would it be a barrel? No. Is it a bucket-full? No. In
fact it’s only about 500 grams, that’s just one pound, would treat all that water for a
month.”


And that’s all it would take, because the lamprey only spawn for a month, but the
treatment would have to happen once a year. Peter Sorensen says when lamprey
approach a stream to spawn, their clock is ticking. They have a powerful urge to lay
eggs, and once they’ve done that, they die.


“They are driven animals. Frankly they’re kind of on autopilot and pheromones are
what’s driving that autopilot to a very large extent, and now that we’ve got it, I think we
can really powerfully use that to our advantage.”


Sorensen says fisheries managers could use the pheromone to attract more lampreys to
streams outfitted with traps.


“You know the key here is the fact that this pheromone is natural, safe, and should be
very inexpensive to add.”


Fisheries managers hope the pheromone will help reduce the cost of controlling the
lamprey and add a new weapon to their arsenal.


The news on lamprey couldn’t have come at a better time for wildlife managers
around Lake Superior. After years of relatively constant numbers, the lamprey
population jumped dramatically this year. Scientists say lamprey may be finding new
spawning grounds in the mouths of streams, where lampricide is less effective. They’re
hoping they can use the pheromone to draw the lamprey to traps further upstream.


For the GLRC, I’m Stephanie Hemphill.

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Pheromone to Help Control Lamprey?

  • The sea lamprey drastically changed the Great Lakes ecosystem. (Photo courtesy of the Great Lakes Fishery Commission)

Researchers say they’ve discovered a migration pheromone
in sea lamprey. It’s a natural attractant that could boost efforts to
control the invasive parasite. The Great Lakes Radio Consortium’s
Stephanie Hemphill reports:

Transcript

Researchers say they’ve discovered a migration pheromone in sea lamprey. It’s a natural attractant that could boost efforts to control the invasive parasite. The Great Lakes Radio Consortium’s Stephanie Hemphill reports:


Each lamprey can kill forty pounds of fish in its lifetime. Managers use a pesticide to keep the lamprey numbers down, but it’s expensive, and sometimes it kills other fish.


University of Minnesota biologist Peter Sorensen says he’s isolated a chemical signal put out by lamprey larvae. The larvae live in streams, and the signal apparently tells adult lamprey that the stream is a good place to lay eggs.


“We’ve got a cue that’s very powerful, very safe, we don’t need very much of it, and it can control the distribution of the lamprey in a way that other things can’t.”


Sorensen says the pheromone can be used to corral lamprey into areas where they can be trapped or treated with pesticide. The pheromone is being tested in a river in Michigan.


For the GLRC, I’m Stephanie Hemphill.

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Cormorant-Killing Policy Ruffles Feathers

  • Cormorant populations have risen exponentially from their previously dismal numbers. (Photo courtesy of the NOAA)

Across the Great Lakes region, the recovery of the cormorant
is booming. But some anglers and resort owners think the cormorants are eating too many of the fish that people like to eat. In some areas, wildlife managers have resorted to killing cormorants on popular fishing lakes. In one case, critics say there’s not enough evidence to justify the killing. The Great Lakes Radio Consortium’s Stephanie Hemphill reports:

Transcript

Across the Great Lakes region the recovery of the cormorant is booming. But some anglers and resort owners think the cormorants are eating too many of the fish that people like to eat. In some areas, wildlife managers have resorted to killing cormorants on popular fishing lakes. In one case, critics say there’s not enough evidence to justify the killing. The Great Lakes Radio Consortium’s Stephanie Hemphill reports:


Larry Jacobson is the third generation in his family to run the Hiawatha Beach Resort on Leech Lake, about two hundred miles north of Minneapolis. Three years ago, on fishing opener weekend, all of his twenty-one cabins were full. This year, he had no guests. Jacobson says the word has spread that fishing is down on Leech Lake. He blames the cormorants. The birds nest on a small island in the south end of the lake. Eight years ago, there were fifty nests; last year, there were two thousand five hundred.


“The cormorants eat about a pound fish a day. The way the population was just exploding out there, you could see writing was on the wall, that this was really going to make dramatic impact.”


Jacobson says his guests are still catching big walleye, but the smaller, pan-sized walleye are getting hard to find.


There are several reasons why the walleye population might be down, but Jacobson and other business owners blame it on the cormorants, and they’ve asked the Department of Natural Resources to do something about the birds.


“Leech needs to be maintained as high quality fishery. There’s such an economic impact to the area from walleyes, that if you don’t maintain it that way, everyone’s going to be suffering.”


(Sound of boat motor)


Resource officials are responding to the resort owners’ concerns. The Leech Lake Band of Ojibwe owns the island. John Ringle is wildlife manager for the tribe.


“Okay we’re headed right at Little Pelican Island right now.”


Little Pelican Island is about three acres of sand and scruffy shrubs. Hundreds of cormorants cover the shore. Ringle says they fish out here in the open waters of Leech Lake.


“They’re omnivorous so they’re eating all sorts of different varieties of fish. Right now they’re probably eating large numbers of perch.”


Ringle is working with state and federal agencies to reduce the number of cormorants nesting here, eating fish, and crowding out other birds, such as the endangered common tern.


Normally, cormorants are a federally protected bird, just like eagles. That’s because they were almost wiped out by the insecticide DDT before it was banned in 1973. But a new rule allows resource officials to harass and even kill cormorants where they’re damaging other wildlife.


This summer, workers are sitting in hunting blinds on Little Pelican Island, shooting cormorants. They use air rifles to make as little noise as possible, so the other cormorants aren’t spooked away.


So far, they’ve killed more than two thousand birds. They plan to leave about five hundred nesting pairs alive. Ringle says nobody’s happy about shooting cormorants, but he says he thinks it’s necessary.


RINGLE: “My philosophy is that as mankind utilizes the resource, we have to manage them, we’re not in finite supply.”


HEMPHILL: “Do you think we know enough to manage them?”


RINGLE: “Not really. I think the public is demanding action prior to any conclusive study being conducted.”


And that’s a big problem for Francie Cuthbert. She’s a professor and cormorant researcher at the University of Minnesota. Cuthbert says the agencies that want to cut down the cormorant population skipped an important part of the management process: finding out what’s actually happening on Leech Lake.


“They’re really being driven by complaints from citizens and resort owners who are concerned about local economics, and who just don’t like the birds; they’re afraid of the numbers. If we responded to all natural resources conflicts this way, we’d be in a state of chaos.”


Cuthbert says even with the cormorants’ dramatic comeback since the days of DDT, there still aren’t as many as there were a hundred years ago. She says rather than kill cormorants, wildlife officials should try to boost the number of fish.


The state of Minnesota is working on that. It’s stocking Leech Lake with walleye for the first time this year. Conservation officials are studying some of the birds they killed to find out what they’re eating. And the state is also limiting what size of walleye anglers can catch so the fish can recover.


That makes resort owners like Larry Jacobson nervous, because he says a lot of anglers don’t like the limits. But at least he’s glad someone’s doing something.


“The fishery is a business, there’s no question about that. If you want to sustain our economy in this area, you’ve got to manage the lake.”


Workers will continue shooting cormorants occasionally through the summer. And the control effort could continue. Experts say it’ll take several years for the fish to recover enough to draw anglers back to the lake.


For the GLRC, I’m Stephanie Hemphill.

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