Tag: plankton

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

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:

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.

Related Links

Ten Threats: The Earliest Invader

  • A bridge for a river... this portion of the Erie Canal crossed the Genesee River via an aqueduct in Rochester, NY. This photo was taken around 1914. (From the collection of the Rochester Public Library Local History Division)

The Ten Threats to the Great Lakes” is looking first at alien invasive species. There are more than 160 non-native species in the Great Lakes basin. If they do environmental or economic harm, they’re called invasive species. There are estimates that invasive species cost the region billions of dollars a year. Different species got here different ways. David Sommerstein tells us how some of the region’s earliest invaders got into the Lakes:

Transcript

We’re bringing you an extensive series on Ten Threats to the Great Lakes. The Great Lakes Radio Consortium’s Lester Graham is guiding us through the reports:


“The Ten Threats to the Great Lakes” is looking first at alien invasive species. There are more than 160 non-native species in the Great Lakes basin. If they do environmental or economic harm, they’re called invasive species. There are estimates that invasive species cost the region billions of dollars a year. Different species got here different ways. David Sommerstein tells us how some of the region’s earliest invaders got into the Lakes:


If the history of invasive species were a movie, it would open like this:


(Sound of banjo)


It’s 1825. Politicians have just ridden the first ship across the newly dug Erie Canal from Buffalo to New York.


(Sound of “The Erie Canal”)


“I’ve got an old mule, and her name is Sal. Fifteen miles on the Erie Canal…”


Chuck O’Neill is an invasive species expert with New York Sea Grant.


“At the canal’s formal opening, Governor DeWitt Clinton dumped a cask of Lake Erie water; he dumped that water into New York Harbor.”


Meanwhile, in Buffalo, a cask of Hudson River water was triumphantly poured into Lake Erie.


“In a movie, that would be the flashback with the impending doom-type music in the background.”


(Sound of ominous music)


It was an engineering and economic milestone, but a danger lurked. For the first time since glaciers carved the landscape twelve thousand years ago, water from the Hudson and water from the Great Lakes mixed.


(Sound of “Dragnet” theme)


Enter the villain: the sea lamprey. It’s a slimy, snake-like parasite in the Atlantic Ocean. It sucks the blood of host fish.


Within a decade after the Erie Canal and its network of feeders opened, the sea lamprey uses the waterways to swim into Lake Ontario. By the 1920’s and 30’s, it squirms into the upper Lakes, bypassing Niagara Falls through the Welland Canal.


What happens next is among the most notorious examples of damage done by an invasive species in the Great Lakes. By the 1950’s, the sea lamprey devastates Lake trout populations in Lake Superior. Mark Gaden is with the Great Lakes Fishery Commission.


“They changed a way of life in the Great Lakes basin, the lampreys. They preyed directly on fish, they drove commercial fisheries out of business, the communities in the areas that were built around the fisheries were impacted severely.”


The sea lamprey wasn’t the only invader that used the canals. Canal barges carried stowaway plants and animals in their hulls and ballast. In the mid-1800’s, the European faucet snail clogged water intakes across the region. The European pea clam, purple loosestrife, marsh foxtail, flowering rush – all used the canal system to enter the Great Lakes.


Chuck O’Neill says the spread of invasive species also tells the tale of human transportation.


“If you look at a map, you can pretty much say there was some kind of a right-of-way – railroad, canal, stageline – that was in those areas just by the vegetation patterns.”


Almost one hundred invasive species came to the Great Lakes this way before 1960. O’Neill says every new arrival had a cascading effect.


“Each time you add in to an ecosystem another organism that can out-compete the native organisms that evolved there, you’re gradually making that ecosystem more and more artificial, less and less stable, much more likely to be invaded by the next invader that comes along.”


(Sound of “Dragnet” theme)


The next one in the Great Lakes just might be the Asian Carp. It’s swimming up the Illinois River, headed toward Lake Michigan. Cameron Davis directs the Alliance for the Great Lakes.


“If this thing gets in, it can cause catastrophic damage to the Great Lakes, ‘cause it eats thirty, forty percent of its body weight in plankton every day, and plankton are the base of the food chain in the Great Lakes.”


The U.S. Army Corps of Engineers has installed an electric barrier in the Chicago Sanitary and Ship Canal that might stop the carp. But as long as the canals around the region remain open for shipping and recreation, it’s likely more invaders may hitch a ride or simply swim into the Great Lakes.


For the GLRC, I’m David Sommerstein.

Related Links

Ten Threats: Predicting New Invaders

  • Some say it's only a matter of time before the Asian Carp enters the Great Lakes. (Photo courtesy of the USFWS)

More than 160 kinds of foreign creatures are in the Great Lakes right now, and every few months, a new one finds its way into the Lakes. Those invasive species are considered the number one problem by the experts we surveyed. The outsiders crowd out native species and disrupt the natural food chain, and it’s likely more will be coming. Zach Peterson reports scientists are putting a lot of time and effort into figuring out which new foreign creatures might next invade the Great Lakes:

Transcript

There are new problems for the Great Lakes on the horizon. The Great Lakes Radio Consortium’s Lester Graham is our guide in a series that explains that new invasive species are one of the Ten
Threats to the Great Lakes:


More than 160 kinds of foreign creatures are in the Great Lakes right now, and every few months, a new one finds its way into the Lakes. Those invasive species are considered the number one problem by the experts we surveyed. The outsiders crowd out native species and disrupt the natural food chain, and it’s likely more will be coming. Zach Peterson reports scientists are putting a lot of time and effort into figuring out which new foreign creatures might next invade the Great Lakes:


(Sound of boat motor)


Jim Barta is a charter boat captain just above Lake Erie on the Detroit River. He says over the last decade, zebra mussels and other foreign species have altered the habitat of the walleye he fishes for.


Water that once had a brownish hue is now clear. That’s because Zebra mussels have eaten the algae and plankton that used to cloud the water, and that means Barta’s boat is no longer invisible to the fish he aims to hook.


“You could catch the fish a little closer to the boat because they weren’t as spooked by the boat. They weren’t as afraid of what was taking place.”


So Barta had to rethink his tactics. He now casts his lines out further, and he’s changed lures to continue catching walleye.


But there are other problems the zebra mussel is causing. Eating all the plankton means it’s stealing food at the bottom of the food chain. And, that affects how many fish survive and how much the surviving fish are able to grow.


Anthony Ricciardi is trying to help Barta, and other people who rely on a stable Great Lakes ecosystem. He’s an “invasion biologist” at McGill University in Montreal.


Ricciardi looks for evidence that can predict the next non-native species that might make it’s way into the Great Lakes. He says species that have spread throughout waterways in Europe and Asia are prime candidates to become Great Lakes invaders.


“If the organism has shown itself to be invasive elsewhere, it has the ability to adapt to new habitats, to rapidly increase in small numbers, to dominate ecosystems, or to change them in certain ways that change the rules of exsistence for everything else, and thus can cause a disruption.”


Ricciardi says most aquatic invasive species are transported to North America in the ballast tanks of ocean freighters. Freighters use ballast water to help balance their loads. Some of the foreign species hitchhike in the ballast water or in the sediment in the bottom of the ballasts.


Ships coming from overseas release those foreign species unintentionally when they pump out ballast water in Great Lakes ports. Ricciardi says one of the potential invaders that might pose the next big threat to the Great Lakes is the “killer shrimp.” Like the Zebra Mussel, it’s a native of the Black Sea.


“And it’s earned the name killer shrimp because it attacks invertebrates, all kinds of invertebrates, including some that are bigger than it is. And it takes bites out of them and kills them, but doesn’t necessarily eat them. So, it’s not immediately satiated. It actually feeds in a buffet style: it’ll sample invertebrates, and so it can leave a lot of carcasses around it.”


Ballasts on cargo ships aren’t the only way foreign species can get into the Lakes. Right now, scientists are watching as a giant Asian Carp makes its way toward Lake Michigan. It’s a voracious eater and it grows to a hundred pounds or more.


This non-native fish was introduced into the Mississippi River, when flooding allowed the carp to escape from fish farms in the South. A manmade canal near Chicago connects the Mississippi River system to the Great Lakes.


If it gets past an electric barrier in the canal, it could invade. Many scientists believe it’s just a matter of time. Another invasive, the sea lamprey, also got into the Great Lakes through a manmade canal.


But, researchers don’t usually know when or where an invader will show up. David Reid is a researcher for the Great Lakes Environmental Research Laboratory in Ann Arbor. He says they can’t predict the effect an invader will have when it arrives in its new ecosystem.


“That’s the problem. We don’t know when the next zebra mussel’s going to come in. We don’t know when the next sea lamprey type of organism is going to come in. Generally, if you look at the invasion history of the Great Lakes, you’re seeing about one new organism being reported probably about once every eight months.”


Knowing what the next invader might be could help biologists, fisheries experts, and fishermen know what to do to limit its spread. Invasional biologists hope that their work will help develop the most effective measures to limit harm to the Great Lakes.


For the GLRC, I’m Zach Peterson.

Related Links

Tumors Found on Zooplankton

  • Large tumors have been found on zooplankton in Lake Michigan. Scientists don't know the cause and don't know what the growths will mean to the food chain. (Photo courtesy of University of Michigan and NOAA/ Great Lakes Environmental Research Laboratory)

Scientists are alarmed at the discovery of tumors on tiny animals at
the base of the food chain in one of the Great Lakes. The Great Lakes
Radio Consortium’s Lester Graham reports… no one seems sure what this
will mean to life in the lakes:

New Invasive Species Found

A new exotic species is invading the Great Lakes. The Great Lakes Radio Consortium’s Lester Graham reports that this new invader has been causing problems for anglers: