invasive - The Environment Report

Weevils vs. The Mile-A-Minute Weed

The mile-a-minute weed (Photo courtesy of the USDA)

Sometimes biologists fight foreign
pests with other foreign animals. But that
can be risky because it can create a bigger
problem than the one it’s supposed to solve.
Sabri Ben-Achour reports on one of the latest attempts to stop a weedy pest:

Transcript

On farms, backyards, and rights of way up the Eastern Seaboard a pointy leaved thorny
newcomer is becoming increasingly visible. It’s called mile-a-minute weed.

Bob Trumbule is an entomologist. He leads me through a stream valley north of
Washington DC where blackberries and small trees are being swallowed up by this
invasive vine.

“So now we’re getting into the mile-a-minute here. Basically what it does it, it’s an
annual vine, it grows up and over plants, it smothers them, out competes them for
sunlight, and weighs them down.”

The weed is native to Eastern Asia: China and Japan. It was introduced accidentally in
Pennsylvania in the thirties. From there, it’s spread to seven other states. It prevents new
trees from sprouting in forests. But back in Asia, it’s not a dominating species like it is
here.

Judith Hough-Goldstein is a professor at the University of Delaware.

“Part of the reason is because it doesn’t have anything that’s feeding on it. It’s gonna be
without its predators so it can out-compete other plants.”

Over several years, biologists searched for something that would eat the vine. They
found a tiny, black weevil in China. It feeds on the plant and lays it’s eggs there, keeping
things in check – in Asia.

“Here are the weevils. I’m gonna give you a glimpse of them here in the cup. They look
almost like little ticks. I’m gonna put them down here in the mile a minute weed patch,
and basically what they’ll do – they’re tough little guys – they’ll climb around and in the
past experience have started to feed almost immediately.”

Up close, they look like little anteaters, poking around the leaves with long snouts.

This may sound risky. There are lots of examples where similar approaches have gone
wrong. A parasite was introduced in North America to control gypsymoths. It attacked
native silkmoths. Mississippi catfish farmers used Asian carp to control algae. They got
loose and are taking over the Mississippi River system and threatening the Great Lakes.

And Trumbule admits nobody knows for sure exactly what might happen.

“Any scientist that might say otherwise is not being honest with themselves or the person
asking the question.”

But he says a lot’s been learned since the days when any scientist could introduce a
species on a whim. These days, exhaustive testing and federal permits are required
before anything is released.

That’s why for almost ten years Judith Hough-Goldstein has been trying to determine if
the weevil would eat anything else. Tests were conducted in a U.S. Department of
Agriculture ‘quarantine facility’ with sealed windows and its own re-circulated air supply.

“So what we found was that, in fact, this particular weevil is extremely host specific. The
insect has evolved to depend on the plant.”

So much so that the weevils and larvae actually starved to death rather than feed on other
plants.

In field tests in New Jersey and Delaware, the weevils have decimated mile-a-minute
weed. Some researchers say it’s the most impressive biocontrol they’ve worked with.

For The Environment Report, I’m Sabri Ben-Achour.

Westward Ho for the Ash Borer

Adult emerald ash borer (Photo by David Cappaert, Michigan State University, courtesy of the Michigan Department of Agriculture)

The emerald ash borer has eaten through
millions of trees in the US and is spreading
west. Erin Toner has more:

Transcript

The emerald ash borer has eaten through
millions of trees in the US and is spreading
west. Erin Toner has more:

For six long years, the tiny metallic-green emerald ash borer has been a killing machine,
starting with millions of ash trees in Michigan and Canada, and then munching its way
into 10 states.

It was recently discovered in Missouri, and now, it’s in Wisconsin.

The prognosis is not good.

Darrell Zastrow is with the Wisconsin Department of Natural Resources.

“Our forests are not typically resilient against non-native species and that is true for
the emerald ash borer. It is generally considered to be a poster child for invasive
species.”

Officials in Wisconsin are doing what everyone else has done – restricting the movement
of firewood and telling people how to protect their trees.

Some promising treatments to fight the emerald ash borer are being tested, but so far,
nothing has worked at keeping the insect from spreading west.

For The Environment Report, I’m Erin Toner.

Keeping a Big Fish From Butting In

Asian Carp can grow up to 110 pounds (Photo courtesy of the US Fish and Wildlife Service)

There are invasive fish swimming their
way toward the Great Lakes. If they get in,
they could swallow up a multi-billion dollar
sport fishing industry. Mark Brush reports,
officials are investing millions of dollars
to keep Asian Carp out of the Great Lakes:

Transcript

Asian Carp were imported by fish farms in Mississippi and Arkansas to control algae.
But the fish escaped during floods. They swam out of the fish ponds, and into the Mississippi
river. And they’ve been moving north ever since.

(sound of boats)

Thad Cook is on a tributary of the Mississippi River in Illinois. This river is more than
400 miles upstream from where Asian Carp first escaped the fish farms.

Cook is looking
for two types of Asian Carp known as Silver and Bighead Carp. It turns out t’s not hard to find them. He dips an electrified pole into the water – and the fish jump right out of the
river and into the boat.

(sound of fish flopping in boat)

Cook is with the Illinois Natural History Survey. His group, along with several others,
has been making trips like this one for years. They’ve been keeping a close eye on where
the fish are going. He takes a guess at how big this fish is.

“No he’ll go… uh.. he’s probably…”

“Hold him out there Jimmy!”

“Yep, six, seven, eight, nine, ten pounds.” (Laughter)

His fish story could have gone a lot further. Some types of these Carp can get up to a
hundred pounds. There aren’t many fish that can compete with an appetite like that.

Biologists are finding that these carp are pushing native fish species aside as they spread
north through the Mississippi River system. And some fear it’s only a matter of time
before they swim their way into the Great Lakes.

David Jude is a fisheries biologist with the University of Michigan.

“I’m very concerned about what impact they would have in the Great Lakes because
they’re planktovores which means they filter zooplankton from the water column. And, they’re just huge fish. And so they have the potential for having
a tremendous impact on our ecosystems.”

He says the silver and bighead carps are filter feeders. They pass up eating smaller fish –
and head straight for the bottom of the food chain.

Jude says if Asian carp get in, it’ll make a bad situation worse. The Great Lakes are
already losing zooplankton from other invasive species. Asian Carp could
destroy a 4 billion dollar a year sport fishing industry.

(sound of canal)

And here is where the battle line is being drawn. The fish have been spotted thirty miles
downstream from this spot on the Chicago Ship and Sanitary Canal. A century ago,
engineers blasted through solid rock to connect the Great Lakes with the Mississippi
River system.

Chuck Shea is with the U.S. Army Corps of Engineers.

“Any type of fish that would want to move between Lake Michigan and the Mississippi
river basin – has to pass through the Chicago Sanitary and Ship Canal – there’s no other way to swim through. So, they have to come through this body of water we’re standing in front
of right now.”

Shea is in charge of the construction and maintenance of two electric fish barriers along this canal.
When this barrier is online, machines will pulse electricity into the water. The electric current shocks
the fish – making them swim away.

This barrier hasn’t been turned on yet. There have been delays due to funding shortages. And they’re still
doing safety testing with the Coast Guard.

Right now, the only thing that would keep the carp from getting into the Great Lakes is a temporary electric
barrier built six years ago.

The good news is that there still seems to be a little time. Biologists say, so far, Asian Carp haven’t moved any
closer than thirty miles from the barrier for the last couple of years.

For The Environment Report, I’m Mark Brush.

Imax Movie Highlights Great Lakes

"Mysteries of the Great Lakes" is an IMAX film highlighting the threats to Great Lakes wildlife (Photo by Lester Graham)

There’s a new IMAX film about the threats to wildlife around the Great Lakes. Chuck Quirmbach has more:

Transcript

There’s a new IMAX film about the threats to wildlife around the Great Lakes. Chuck Quirmbach has more:

The film “Mysteries of the Great Lakes” highlights some less commonly known stories, like that of the massive fish known as the lake sturgeon. Biologists are trying to bring the threatened fish back to healthy numbers.

Ron Bruch is a key figure in the new movie. Here, he discusses a 120 year old female sturgeon he’s seen numerous times on spawning runs.

“I’ve gone through this ritual eight times with this fish, and each time I wonder if it’ll be the last. But she’s a survivor and maybe 50 years from now, she’ll come up this river looking for me, and I’ll be gone.”

The film also looks at possible health risks to bald eagles, and what invasive species are doing to native wildlife.

“Mysteries of the Great Lakes” has started its run in several U.S. and Canadian cities.

For The Environment Report, I’m Chuck Quirmbach.

Sea Squirts Sucking Up Species

A colony of tunicates in Guam (Photo by David Burdick, courtesy of NOAA)

Slimy, hungry invaders are moving through
the waters off the Northwest coast of the US.
They’re called invasive tunicates –
or sea squirts. And they’re the same invasive
species that devastated shellfish farms on Canada’s
east coast. If invasive tunicates aren’t controlled,
you could see a lot of seafood options disappear
from markets and menus. Ann Dornfeld has the story:

Transcript

It’s a peaceful spring morning at this suburban marina. But beneath the water’s surface, a hunt is
underway.

(water sounds)

Professional divers – like Jesse Schultz with the Washington Department of Fish and Wildlife – are
combing the docks for invasive tunicates. They don’t have to look far.

“That’s one of the tunicates right there – that’s the guy right there.”

Schultz surfaces holding a jelly-like tube. Sea squirts compete with everything from clams to tube
worms for the plankton they all eat. The sea squirts usually win, because they don’t have native
predators. Three species came here from Asia, probably on boat hulls. Today, divers are cleaning
the hulls of local boats to keep the sea squirts from spreading.

Allen Pleus manages invasive species for the state.

“The whole intent right now is a containment action. We want to prevent any of these boats
from leaving this harbor with the tunicates attached to their bottom, going to another
harbor, and infesting that harbor or marina.”

When invasive tunicates get to a new harbor, they quickly become the dominant species. In the
warm part of the year, they spawn every 24 hours. And along with hogging the food supply, one
species of sea squirts forms a slimy mat that smothers mussels and other shellfish.

Pleus says if tunicates get out of hand, they could make a big impact on the seafood industry.

“It can definitely affect especially shellfishing in this area. Puget Sound, Western Washington is one of
the largest producers of shellfish in the nation. It could also affect other populations of
food fish, including salmon, by taking out a lot of the nutrients that juvenile salmon feed
on.”

Nova Scotia learned that lesson the hard way. Pleus says in Eastern Canada, entire shellfish
farms were recently wiped out by invasive tunicates.

“So the rap sheet is clear. They can grow to exponential sizes, quantities and smother
aquaculture facilities. They can’t even lift up their lines it’s so heavy with these critters on
it.”

To prevent the same thing from happening here, the state workers have to move quickly – and
they have to be thorough.

“Here’s another bag, Justin!” (splashing sound)

Back in the water, diving biologist Jesse Schultz has his hands full with a boat that has apparently
been docked for seven years. Its tabs show that’s the last time it was registered.

“This guy’s getting a free boat cleaning, sort of!”

The state is trying to scrape clean every infested boat in Puget Sound before the summer boating
season. But Schultz says because the docks are still covered with invasive tunicates, they’ll grow
back on this boat if the owner doesn’t keep it clean.

“That’s the biggest thing these guys can do to keep these things from spreading is have
their boats maintained.”

The state is still figuring out the best way to clean the docks. So far biologists have cleaned only
one entirely. When they were done, they’d removed ten tons of critters.

Unfortunately, Allen Pleus says only some of those were tunicates. In order to get rid of the
invasive sea squirts, they have to employ a sort of scorched earth policy.

“That is one of the hardest parts of this is that we have to basically take everything out.”

That means the good with the bad. We sift through a bucket of the creatures scraped from the
dock. Along with plenty of invasive tunicates, there are brightly colored sea cucumbers, scallops,
mussels, rock oysters, feather duster worms and chitons – exactly the kinds of animals the state
is trying to protect. They have to destroy the habitat in order to try to save it.

For The Environment Report, I’m Ann Dornfeld.

Sea of Controversy for Hawaii’s Superferry

Hawaii's Superferry was met with initial excitement, but it quickly turned to environmental concern (Photo courtesy of Hawaii Superferry)

For decades, people who wanted to get from
one Hawaiian island to another have had one main
option: flying. So when plans were unveiled for
a high-speed ferry between the islands, Hawaiians
and tourists were initially thrilled. But growing
concern about the Superferry’s potential environmental
impact has turned the issue into one of the state’s
biggest legal battles in years. Ann Dornfeld reports:

Transcript

David Dinner is board president of the environmental group 1000 Friends
of Kaua’i. He lives near this small beach on the island’s north shore.
Dinner says when endangered humpback whales come to Hawaii in the
winter to give birth, you can whale-watch right from this beach. Even
when he lived far from the ocean, he once witnessed a huge migration
from his window.

“I could see that the ocean was filled with whales. And I later found out that there were 6,000 whales around Kaua’i at that
time. So it was like wall-to-wall whales out there.”

When Dinner first heard about plans for a high-speed inter-island
catamaran, he was excited. But the more he and others learned about the
Hawaii Superferry, the more they worried about its effect on those whales.

Mother whales spend a lot of time just below the surface, pushing their
calves up for air. The concern is that the ferry’s twin hulls would strike the
whales at a speed of up to 45 miles per hour. That’s a lot faster than other
boats like cruise ships and tankers.

“The other boats that travel in this area generally go in the area of 13 to 15
miles an hour. So the Superferry is way beyond the speed of the other boats.”

Another big worry was that the car ferry could bring invasive species from
one island to another. For instance, mongooses decimated the Big
Island’s bird population. But Kaua’i doesn’t have mongooses yet.

Rich Hoeppner is founder of the Superferry Impact Group.

“We have an incredible selection of birds here. We have shearwaters,
albatross, the state bird – the Nene, is a land-dweller and endangered
species. So one pregnant mongoose gets on our island, our bird
population will be history.”

When activists learned that the state government had given Hawaii
Superferry the green light without an environmental impact statement,
they filed suit. Last August, the state Supreme Court ruled that the state
should have required an environmental impact statement.

Despite that, just two days later, Superferry made its maiden voyage to
Kaua’i.

Rich Hoeppner says two dozen surfers and kayakers blocked the
boat’s path to Nawiliwili Harbor for hours.

The next night, protesters crowded the harbor, and dozens more people
took to the water – some in traditional Hawaiian canoes. Protesters
filmed the action.

(sound of protest chants)

“After 3 hours, the ferry, which was at the mouth of the harbor, turned
around and went back to Oahu. It didn’t get to its dock. And it hasn’t been
back since!”

Hawaii Superferry says it takes the environment seriously.

Terry O’Halloran is Director of Business Development. He points to the
company’s efforts to keep invasive species from hitching
a ride on vehicles.

“We look under the hood, we look in the trunk, we look in the wheel wells,
we look inside the vehicles, and then a certain number of vehicles that go
through our security screening get a much more thorough screening and
inspection.”

O’Halloran says vehicles with muddy tires aren’t allowed on board in case
bugs or seeds are in the dirt. There are boot scrubbers for passengers,
too. On-board videos warn travelers about the dangers of invasive
species.

O’Halloran says Superferry also has a Whale Avoidance Policy that
includes avoiding the main calving areas during whale season, and
slowing down in whale zones.

“We have been able to spot and avoid the whales. We also have two dedicated
whale lookouts and their only job is to help the captain spot whales.”

Superferry is still making its Oahu-to-Maui trips. In a special session,
Hawaii legislators passed a law allowing the Superferry to keep
running while the state conducts an Environmental Impact Statement.

Protestors say that’s a terrible idea – and illegal. They’re pursuing
lawsuits in the state Supreme Court to dock the ferry until it’s clear the
boat is safe.

For The Environment Report, I’m Ann Dornfeld on Kaua’i.

A Silver Bullet for Zebra Mussels?

Zebra mussels were discovered 20 years ago, and have since spread across the country (Photo courtesy of the US Fish and Wildlife Service)

Researchers say they’ve found something
that will kill invasive zebra and quagga mussels.
The mussels got into the US in the ballast of
foreign ships. Since then they’ve spread throughout
the country. Rebecca Williams reports:

Transcript

So, let’s say you have a nasty pest, an invasive species. Then someone says, we can get rid of that
pest and it looks like there’s no environmental downside.

“It kinda sounds like snake oil. But it’s true.”

That’s Dan Molloy with the New York State Museum lab. He’s come up with a
way to kill zebra and quagga mussels.

Molloy says a strain of common bacteria is toxic to zebra and quagga
mussels. And, even if the bacteria are dead, they can still kill the
mussels.

“You know maybe horror stories of people applying biocontrol agents. And it
had effects they didn’t anticipate. We’re applying dead cells. And they’re
just as effective live or dead.”

It’s great news for power plants, because the mussels clog up intake
pipes.

But it’s not clear if the bacteria can kill mussels in open water.

For The Environment Report, I’m Rebecca Williams.

Ballast Tanks: Rinse and Repeat

Crew chief Mohammed Sangare tests the "Federal Kivalina"'s ballast tanks for invasive species. (Photo by David Sommerstein)
The St. Lawrence Seaway's Terry Jordan shows off the refractometer that tests the ballast water for salinity. (Photo by David Sommerstein)

The United States and Canada are trying to
figure out how to keep new invasive species out of
the Great Lakes. 185 have already snuck in, costing
the region billions of dollars a year. Many
hitchhiked in the ballast tanks of foreign cargo ships.
Both countries want the public to know they’re doing
something about the problem. So they invited journalists
to the port of Montreal to see how ballast tanks are
tested for invasive species. David Sommerstein
reports:

Transcript

A couple dozen reporters crowd the deck of the cargo ship Federal Kivalina.
Cameras click, pencils scribble, and tape rolls as a man in a bright orange
uniform steps forward to test for invasive species.

“My name is Mohammed Sanare.”

(sound of tape measure sliding down)

Sangare is the bosun, the crew chief. He slides what looks like a metal tape
measure down a tube. It’s the opening of one of the Kivalina’s 16 ballast
tanks.

“Down to the bottom now. The bob’s down to the bottom.”

The tape hits the tank bottom, and Sangare reels it back up.

Terry Jordan, a St. Lawrence Seaway official, is waiting with a handheld
gizmo. It’s a refractometer that tests water salinity. He carefully places a
drop of ballast water on it.

“All it takes is one drop of water on the refractive lens, OK.”

Jordan peers through the refractometer’s lens. It reads 38 parts salt per 1000
parts water.

Recent scientific studies show that concentration of salt water kills up to
99% of the organisms hidden in these ballast tanks. That’s important
because those critters can compete with native species and damage whole
ecosystems.

David Reid is a researcher with the National Oceanic and
Atmospheric Administration.

“Salinity was very effective at killing many of the organisms that we would
expect to be able to survive in the Great lakes.”

So for the first time this year, all ships voyaging into the Great Lakes have to
do something that sounds like a mouthwash ad.

“Swish and spit.”

Yeah, “swish and spit”. Terry Jordan says on its way across the ocean, the
ship flushes its ballast tanks with salt water, and presumably, kills potential
invasive species. The refractometer test is proof of the swish and spit. If the
ship fails, its ballast tank is sealed and its owner is fined up to 36,000
dollars.

“Swish & spit” has been voluntary for years. Environmentalists say the new
mandatory rules are a step in the right direction, but too little and way too
late.

“Some would argue that the dam has already burst.”

Hugh MacIsaac specializes in invasive species at the Great Lakes Institute
for Environmental Research in Windsor, Ontario. He says if ships were
“swishing and spitting” from the beginning, we might have been able to
prevent the zebra mussel, round goby, and other invasions.

But, MacIsaac warns there are other species lurking on the horizon, like
one in Germany, ominously called the killer shrimp.

“And so any protective measures that we put in place today that would
prevent or retard their ability to get in, I would welcome.”

Scientists doubt anything can be fool-proof. Invasive species still can hide
other places on the ship. And the new rules do nothing to stop salt-water
invaders like the mitten crab from attacking ports on the East and West
Coasts.

Terry Johnson is the St. Lawrence Seaway’s U.S. Administrator. He says
“swish & spit” is a huge step forward for the Great Lakes.

“So does that mean that it is absolutely, definately 100% positively assured that there
won’t be invasives coming in with these new regulations? No, it’s doesn’t.
But it dramatically reduces the risk.”

Congress is considering even tougher rules that would force shippers to
install cutting-edge ballast cleansing systems. The proposal could cost up to
a million dollars per vessel. The Bush Administration has threatened a veto.

For The Environment Report, I’m David Sommerstein.

New Ship Has Balance Without Ballast

A diagram of the ballast-free ship (Photo courtesy of Professor Michael Parsons)
The stern of the model showing the two discharge locations on the ship. It was tested last summer. (Photo courtesy of Professor Michael Parsons)

Cargo ships move sea life around the world.
Moving aquatic life from one port to another can cause
environmental havoc. Lester Graham reports there’s a
new idea that could nearly eliminate the problem of
transporting sea life to foreign ports:

Transcript

There is an invasion of every major port on the globe.

“Today, the world’s shores are under attack. Armies of aliens are secretly invading our coasts.”

If this video, Invaders from the Sea, from the International Maritime
Organization sounds a little over-dramatic, it’s really not. Invaders from far-flung
corners of the world are brought in by commerce. In their travels, cargo ships pick up the
hitchhikers.

Those hitchhikers can be fish, mussels – aquatic bugs of all kinds. They can become
pests. Out-compete native species for food and space. They can destroy the
native ecosystems and often damage the economic well-being of people.

Here’s how it happens. Ocean-going cargo ships dock at a foreign port. They pump in
water for ballast to keep the ship stable. They also pump in some of the living things in
the water. When they arrive at the destination port, they can pump out that water and
the critters that were sucked up with it.

In the US, ports from Chesapeake Bay to San Francisco have been invaded. But,
the Great Lakes have been hit especially hard by invasive species.

Michael Parsons is a professor of naval architecture at the University of Michigan. He
says when foreign ships were able to come in from the Atlantic and travel as far as
inland as Duluth, Minnesota; they brought a lot of invaders with them.

“With the opening of the St. Lawrence Seaway in the ‘50’s, that led to increased
introduction of non-indigenous species such as the zebra mussel, and the round goby, and
the ruffe, and the various smaller creatures that have been brought in to the Great Lakes.”

Those creatures have damaged the ecosystem of the Great Lakes. And they’ve cost the economy.
By one Environmental Protection Agency estimate about five-billion dollars a year.

Parsons and his colleagues have been working to design a ship that has no need for
ballast. In the lab, a scale model has been tested in a long pool. Instead of pumping
water in and out of the ballasts, the water would flow through big
tubes that run the length of the ship.

“And so, that’ll create a slow flow through these trunks so that they’re always swept
clean of foreign water.”

“A ship like that is just what we need in the Great Lakes.”

Andy Buchsbaum runs the Great Lakes office of the environmental group, the National
Wildlife Federation.

“If you eliminate the need for ballast water altogether, then you’re eliminating the vast
majority of invasive species introductions that come in through the discharge of ballast.”

The ballast-free ship design is creating some excitement. Even the shipping industry is
paying attention because the ship also is more fuel efficient.

If someone decides to actually build the ballast-free cargo ship, it’ll be a while before
the first one is on the high seas.

Allegra Cangelosi has been working on the ballast and invasive species problem for
close to a decade. She’s a policy analyst with the Northeast-Midwest Institute.

“I think it’s a wonderful development. I don’t think there’s going to be any one answer
for all ships plying all waters throughout the globe. However, the more good answers
that are out there to choose from, the better for the environment.”

Some of those choices are filtering ballast water or killing organisms in the ballast with
chemicals. Those systems are expensive. And since fuel isn’t getting any cheaper, that
might make a more fuel-efficient ballast-free ship attractive.

For The Environment Report, this is Lester Graham.

Big Ships Required to Flush

A ship discharging its ballast water (Photo courtesy of the US Geological Survey)

Ships should be bringing in fewer unwanted
pests into the Great Lakes. Both Canada and the
U-S are now requiring ships to flush out their
ballast water tanks before entering the lakes.
Tracy Samilton reports:

Transcript

Ships should be bringing in fewer unwanted pests into the Great
Lakes. Both Canada and the U.S. are now requiring ships to flush out their
ballast water tanks before entering the lakes. Tracy Samilton reports:

Ships need to take on ballast water to keep them stable. When they pump in
water from freshwater foreign ports, they also suck up pests.

Since 2006,
Canada has required ships to flush their tanks with salty ocean water
before entering the Great Lakes. The U.S. adopted the requirement at the
start of this year.

Collister Johnson is with the U.S. side of the St.
Lawrence Seaway, which connects the Atlantic Ocean to the Great
Lakes. He says the rule will eliminate almost 99% of freshwater
pests in ballast tanks.

“If they’re exposed to salt water, especially full strength sea water, they
are effectively killed.”

Samilton: “Why didn’t we do this before?”

Johnson: (laughs) “I don’t know.”

It won’t completely eliminate the problem because some aquatic pests can
still survive in the sediment in the bottom of ballast tanks.

For The Environment Report I’m Tracy Samilton.

Tag: invasive

Weevils vs. The Mile-A-Minute Weed

Transcript

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Westward Ho for the Ash Borer

Transcript

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Keeping a Big Fish From Butting In

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Imax Movie Highlights Great Lakes

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Sea Squirts Sucking Up Species

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Sea of Controversy for Hawaii’s Superferry

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A Silver Bullet for Zebra Mussels?

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Ballast Tanks: Rinse and Repeat

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New Ship Has Balance Without Ballast

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Big Ships Required to Flush

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