Captioning provided by Extension and Experiment
Station Communications at Oregon State University.
Narrator: An ecosystem.
It's a community of plants and animals.
What we see at the surface is only part of the picture.
In an ecosystem,
everything is related.
And those relationships have evolved over thousands,
even millions of years.
We use the resources of ecosystems.
We need the resources they provide.
And so, we are also linked to the organisms
that call these natural places home.
Over time,
some members of the ecosystem disappear.
And new ones come in.
These are changes that have taken place
at nature's pace.
The system had time to adjust to the loss
and the gain of new species.
That is, until we started looking
at ecosystems with an eye for change,
and began introducing organisms into waterways
beyond their natural range.
Introducing aquatic organisms into new areas
is a widespread phenomenon that takes many forms.
While some species are shipped from distant places,
others are carried to a nearby drainage.
Some are introduced for economic reasons,
some for recreational pursuits,
and some are the unintended result of our activities.
But no matter what the method,
the distance, or the purpose,
a species that gets into a waterway as a result
of human activities is a non-native species,
an aquatic introduction.
The Chinese first introduced aquatic animals.
About 3,000 years ago,
they domesticated the carp and began placing
them into rivers throughout the country.
By the Middle Ages, Asian carp
had been introduced in Europe�
first in monastery ponds where the fish became
a food source for monks who didn't eat red meat,
and eventually into natural waters throughout
the continent.
Across the Atlantic,
it was barely 100 years after Columbus arrived
that the first foreign fish were introduced
to the New World.
Goldfish,
a relative of the Asian carp,
were planted into North American waters
in the mid-1600s.
The first large-scale aquatic introduction
to North America came in 1872.
Again it was the carp,
brought from Germany to Northern California
by a businessman with a dream.
Julius Poppe was an entrepreneur who hoped
to raise carp and sell them across the country.
He was sure Americans would come to love carp
as the Europeans did.
Only five of his fish survived the trip,
but that was all it took.
Carp are hardy,
and these five were ready to breed.
And breed they did.
In no time,
Poppe began selling hundreds of his carp
to farmers everywhere.
Thanks to the railroad and fish transport cars,
carp were soon raised in ponds throughout the country.
But before long,
spring storms and flash floods
washed carp out of their ponds and set them
free in America's rivers and streams.
They adapted quickly to the wild.
It wasn't long before they could be found
in almost any suitable body of water.
But, in less than twenty years,
many saw the carp introductions as a huge mistake.
Americans didn't take to their taste as Europeans did.
Anglers complained the fish were bony
and hard to clean.
And carp were also unpopular for the damage
they did to natural ecosystems.
To feed,
carp suck in a mouthful of mud, insects, clams,
and other invertebrates found along the bottom
of a waterway.
They spit out the mixture so the particles
are suspended,
and then suck in the food.
In the process, they stir up silt and mud,
making the water cloudy and lowering the visibility.
The habitat becomes less suitable for other
fish who need clear water to find their prey.
As the problems created by carp became more apparent,
agencies began looking at ways to get rid of the fish.
In a number of states,
seining, trapping,
and even adding toxins to the system have been
tried with little success.
It seems carp are here to stay.
This practice,
of taking a species and planting it into
an area beyond its normal range,
continues today.
Since the lessons learned from the carp introductions,
it's hoped all introductions are well-studied
and well-planned.
But sometimes they're not.
Sometimes we don't even know we've introduced
an organism until it becomes a nuisance.
Probably the most dramatic example of our time
has been the accidental introduction of
the zebra mussel.
A small mussel from Europe's Caspian Sea,
it most likely arrived here in the ballast
water of a ship.
Since its discovery in Lake St. Clair in
the Great Lakes basin in 1988,
its numbers have exploded.
Within a year,
colonies of 30,000 to 40,000 per square
meter were found in Lake Erie.
By 1994, zebra mussels had spread to all
of the Great Lakes,
throughout the Mississippi Valley,
and east to New York's Hudson River.
And as they've spread,
zebra mussels have left a path of serious problems.
The little organisms can attach themselves
to any solid surface,
including each other.
In some places they've been found in layers
8 to 12 inches thick.
These layers have clogged intake pipes of
industrial facilities,
power plants, and municipal water suppliers.
In the short time they've been in this country,
their damage has cost millions.
The potential ecological impact of zebra mussels
is equally dramatic.
Each mussel filters about a quart of water a day,
feeding on microscopic organisms.
Organisms that are food for small fish who
are eaten by larger fish and eventually humans.
Given their voracious feeding habits,
and their tremendous numbers,
zebra mussels have the potential to alter
entire ecosystems and disrupt aquatic food webs.
While the ballast water introductions are
an unintentional result of human activities,
other organisms are introduced into our
waters on purpose.
(Plane soars by)
Often, the reason is simply to add a species
in hopes it will survive to produce something
that's desirable to a group of people.
However, in the zebra mussel example,
introduced species are not isolated from
the community of plants and animals they
now share a home with.
Stan Gregory: All introductions change communities.
Whether that's bad or good depends upon our
perspective of the function of those communities.
It does bring change.
They are different.
And then the consequences have to be weighed
through time as to how that new community can
function and what that does to the previously
existing community.
Narrator: While we know a community will be
affected by an introduction,
it can be difficult to accurately predict
what those changes will be,
including any potential negative impacts.
Flathead Lake in northwestern Montana is
the largest natural freshwater lake in the
western U.S.
In 1916,
kokanee salmon were introduced for sportfishing.
Their numbers increased dramatically over the years.
Stanford: By the 1950s,
there were so many fish spawning on
the shoreline that,
after they die,
after spawning,
these fish die after spawning,
there were so many dead carcasses on the shoreline
they had to be collected and carried away
in a dump truck in order to make the area
suitable for people to be around.
Narrator: A land-locked form of the red salmon,
kokanee generally lived for three to four years
in the lake and then spawned either along
the shore or up McDonald Creek,
one of the lake's tributary streams.
As the salmon population grew,
so did the number of anglers.
Flathead Lake became one of the most popular
fishing spots in the west.
But the kokanee boom was a phenomenon destined
to change when another non-native species,
the tiny opossum shrimp, or mysis shrimp,
was introduced into the Flathead Lake basin.
Stanford: Mysis shrimp were introduced into
lakes upstream from Flathead Lake where kokanee
were also introduced previously,
in an attempt to elevate the populations
of the kokanee and make a more viable fishery
for people to harvest.
Unfortunately,
water flows downhill,
and gradually,
after a period of several years,
the mysis showed up in Flathead Lake
and established a population here.
And like most exotic species,
this little shrimp became very abundant
in Flathead Lake in a matter of just a few years.
We first found it in the lake around 1981-2,
and by 1984 and -5 the numbers were up
to about 120 mysis per square meter on
the surface of the lake.
So they just exploded in numbers.
Narrator: Meanwhile,
biologists were counting the salmon migrating
up McDonald Creek.
Stanford: Well this is a typical bar
for red salmon to spawn on.
Narrator: In some years,
more than 100,000 salmon made the trip.
The highest number recorded was 400,000.
But in 1987, something went wrong.
Only 330 salmon made it to the creek that year.
The next year,
only 50.
And while anglers had been taking up to 200,000
kokanee a year,
not a single kokanee was caught in 1988 or '89.
The Flathead Lake salmon population crashed.
And it hasn't come back,
despite re-stocking efforts.
University of Montana researchers found two
problems in this complicated situation.
First of all,
kokanee and mysis were not at the same place
at the same time.
Stanford: Kokanee live in the upper layers
of the water column of this big deep lake,
they don't go into the deep layers because
it's too cold for them.
The mysis, on the other hand,
are adapted to living in the deep layers.
We have a layer of Mysis right here,
They were about 68 meters...
Narrator: Mysis do come up to the surface to feed,
but only at night.
And they return to the lake bottom during the day.
But kokanee only feed during the day.
So when it came time for the salmon to eat,
the mysis weren't there.
A second problem was in the food supply.
Kokanee eat zooplankton,
tiny organisms that drift in currents.
And so do mysis.
Stanford: that gave the mysus a distinct
competitive advantage.
Because they could feed on the zooplankton
very effectively,
their population grew to large numbers very quickly,
and almost before we knew it,
they had eaten the entire food supply
of the kokanee salmon.
Narrator: The effects of the shrimp introduction
were felt throughout the ecosystem.
Flathead Lake and its tributaries had become
a gathering place for a variety of animals
who had one thing in common:
they ate salmon.
Bald eagles were among the most prominent.
Hundreds gathered along McDonald Creek
to eat dead and dying salmon.
But when the kokanee population collapsed,
the animals who had come to depend on salmon
as a source of protein either disappeared
or declined dramatically.
Most introductions are made with the best
of intentions.
Most are based on perceived social or economic
needs of the day.
And sometimes,
well-planned and well-run introductions
can make a positive difference.
Some of the benefits include an increased
food supply...
recreation ....
and pest control.
But in some cases,
the needs of the past aren't necessarily
the needs of the present or the future.
And what we're learning is that while
the intentions of past introductions
were well meaning,
non-native organisms can create unforeseen
complications in natural ecosystems.
In one type of introduction,
a species is added to a community in the hopes that
it will control or eliminate an undesirable species.
It's a type of introduction called biological control.
For example, mosquitofish are used as a biological
control species in rice fields where mosquitoes
can be a serious health problem.
Joe Cech: Mosquitofish are not a cure-all, it's
not a panacea,
it's all effective tool,
and if used properly,
it can be a very effective biological control
of mosquitos,
but like all introduced species we have to be
very careful and very concerned that we use
it in the right way.
Narrator: In the desert Southwest,
mosquitofish introductions threaten native species.
Along the Colorado River,
the Gila topminnow flourished until mosquitofish
were introduced.
The topminnow population is now on the brink
of extinction.
One reason for the decline...
mosquitofish eat young topminnows.
In some areas,
topminnows have disappeared within two years
of a mosquitofish introduction.
It's a similar story in Arizona.
Mosquitofish are one of the several species that
have been introduced into desert pupfish habitats.
Since these introductions,
the number of pupfishes has rapidly declined.
Ironically,
some of the species mosquitofish are helping
to eliminate also eat mosquito larvae.
Both Gila topminnows and desert pupfishes,
if left alone,
are quite effective at mosquito control in
their natural habitats.
Another reason for introducing species beyond
their natural range is to develop or improve
a fishery.
Either the game species themselves or bait
for game species.
Today, anglers may try their luck on bass,
crappie, catfish,
and many others,
hundreds of miles from their native streams.
In fact,
more than one-quarter of all of the freshwater
fish caught by anglers in the United States
are not native.
But what are the effects of these introductions
on the receiving ecosystems?
Introduced species interact with natives in
a number of ways.
An introduced species may breed with a related
native species.
Apache trout were abundant in the streams
of Arizona's White Mountains.
But when introduced rainbow trout bred with
the native Apache trout,
the native population plummeted.
Hybridization can affect the fitness
of the native species.
It has a more difficult time coping with
environmental stresses.
In the case of the Apache trout,
where once they occupied 600 miles of streams,
today they can be found on only 30 miles.
California's state fish,
the golden trout,
nearly disappeared when brown trout made their
way into the Kern River system.
The golden trout couldn't compete with
the larger browns.
And they were easy prey for the newcomer.
Largemouth bass are another predatory game fish
that can impact a native species.
Largemouth bass are native to the Mississippi
River drainage and the southeast,
but they've been stocked outside their native
range for sportfishing more than any species
except perhaps the rainbow trout.
Bass are a great fighting fish and fun to catch.
But that aggressive instinct means trouble
for native organisms that haven't evolved
to deal with this newcomer.
Bass are good predators and competitors
and their introductions have been linked
to the decline of many fish now listed
as threatened or endangered.
Historically,
fishery managers have given people what they wanted:
they've stocked and restocked ecosystems
with the desired species.
But success has often led to increased expectations
for more and more fish.
Yet, today we understand that some
of these introductions have led to a decline,
and in some cases even a complete loss,
of a native species.
And the loss of even a single species can
make a difference.
Stan Gregory: It's important to have many
different life forms.
Not only for the multitude of functions that
they provide,
but also for the functions that they provide
that we aren't aware of.
We don't know everything about our world
and we don't know everything that these species
provide for us.
And,
actually, there are probably
organisms in the environment
that are vital to our very existence.
We know that natural ecosystems support human
life by providing purified air,
fresh water, soil production, waste disposal,
a supply of nutrients and energy,
and the high quality of our atmosphere.
So while it may be tempting to add our favorite
game species to waterways everywhere,
we don't have a clear understanding of how
our actions will change ecosystems that all
living organisms,
including humans depend upon.
Direct introductions aren't the only way
non-native species enter our waterways.
Some organisms find their way by escaping
from holding ponds or aquaculture facilities.
One escape route is to ride on the crest
of a storm or flood.
Dennis Lassuy: As we saw very plainly from
Hurricane Andrew and the recent Mississippi river floods,
things don't always stay where you think
they're going to stay or where you want them to stay.
Narrator: Some species escape by swimming through
unscreened pipes in an aquaculture facility...
or during transport...
and sometimes they have been mixed up
with other species being removed from a pond.
Tilapia, for example,
are native to Africa and parts of the Middle East.
They were originally introduced into North America
as aquarium pets.
Today, the tasty fish are grown commercially for food.
But Tilapia have escaped from holding facilities
and entered natural waters many times.
In warm water states like California,
Arizona, Florida, and Texas,
escapees have successfully adapted to the wild.
Some Tilapia species are very aggressive
and compete with native fish for spawning
sites and space.
They may dig holes to spawn and in the process
uproot plants and increase the silt in the river
which can destroy the nests of other fish
and lower the visibility.
Adding to all this,
certain Tilapia species can breed every month.
And because the parents guard them,
the young have a high chance of survival,
resulting in explosive populations.
Many aquaculture facilities are careful
and follow precautions to prevent species
from escaping and entering adjacent waterways.
If all facilities used the same care,
the problem of species entering natural
ecosystems as escapees could be virtually
eliminated.
Often established non-native species are organisms
imported for the aquarium trade.
Some have been released by home aquarium owners.
Mother: "Kids Just dump that fish"
Narrator: Although people's intentions may have
been good when they released their pets,
these introductions haven't been without
their adverse affects.
Goldfish, for example,
have been found in the waterways of nearly
every state in the Union.
But the pretty little fish can revert to their
wild state and develop voracious appetites.
Feeding mostly on aquatic plants,
goldfish can remove significant amounts
of vegetation.
They increase turbidity and contribute to
the decline of invertebrates living in a community.
Introduced plants can also pose problems.
Hydrilla is an aquarium plant that was
apparently introduced in Florida presumably
by individuals cleaning out their home aquariums.
Native to Asia,
Hydrilla flourishes in the wild.
Once established,
Hydrilla grows quickly.
The plant has taken over 90 percent
of this Florida lake,
and covers large areas of other lakes
in the region.
It clogs waterways and has become a nuisance
to navigation.
Since its introduction,
Hydrilla has spread throughout the southeast
and beyond to California, Iowa, and Virginia.
Hiram Li: The reason why exotic species take
off and explode is because they come over
without the system that provides the natural
checks and balances on population growth.
In other words,
these species have adapted to predators,
competitors,
and diseases in another ecosystem.
And when they're transferred to a new one,
the rules of the game are different.
As a matter of fact,
it may be that the new ecosystem doesn't
have a way to check its population growth.
And when that happens,
the aliens become pests.
Narrator: Bait bucket introductions are another
way individuals have transplanted fish
into America's waterways.
An end-of-the-day bait release is presumably
how red shiners showed up in
Nevada's Lake Mead.
The red shiner is a popular bait fish
native to the northeast,
but sold as live bait in some areas of the west.
Once in the lake,
the red shiners traveled up into the Virgin River.
And with the shiner came a parasite.
The Asian tapeworm found its way
to North America when Asian grass carp
were introduced.
And while shiners have been able to adapt
to the effects of the tapeworm,
the native species in the Virgin River have not.
The woundfin minnow in particular is now
an endangered species partly because it's
not able to deal with the effects
of the Asian tapeworm.
At Klamath Lake in southern Oregon,
Oregon State University researchers are
monitoring another bait species,
the fathead minnow.
Dave Simon: The fathead minnows are a species
of the family cyprinidae which are native
to the eastern and midwest states of
the United States.
And they've been brought out west as people
moved out west,
either for use in fishing as bait fish,
or to feed the fish like largemouth bass
and crappie that they brought out to raise
themselves from the Midwest.
They were first captured in Oregon in the late 70's
in the Klamath River south of the city
of Klamath Falls.
And they were first collected in 1982
here in Upper Klamath Lake
by Oregon Department of Fish and Wildlife.
Since 1982,
they've become the most abundant fish
in Upper Klamath Lake.
Narrator: Not only are the number
of minnows increasing,
they're also spreading to other waterways,
leaving researchers wondering what the effect
will be on two native suckers.
Dave Simon: I've seen a lot of larval suckers
Some laboratory experiments
by some local biologists have indicated that,
at least under laboratory conditions,
the fathead minnows will attack
and kill and eat larval suckers.
Whether that happens in the wild we don't
know the answer to that yet.
Narrator: But one thing seems clear.
Once an introduced species establishes
a successful breeding population
in a new ecosystem,
there's almost no way to get rid of it.
And, as we've seen,
introductions often threaten the cornerstone
of an ecosystem...
biodiversity.
Mario Salazi: It's like the analogy of
the watchmaker and the person who tinkers
with the watch.
If you lose parts of the watch,
the watch won't work anymore.
And with the ecosystem,
it's the same way.
All of the parts are important.
And for the whole ecosystem to function,
it needs all of its parts.
Narrator: The story of aquatic introductions
isn't simple.
There are benefits.
There are costs.
And there are impacts that we don't yet understand.
The aim in aquatic management is not to try
and return to the pristine environments
that existed 500 years ago.
We can't undo past mistakes.
But by carefully researching proposed introductions,
we can better understand the system
and the species we want to introduce.
We can evaluate potential impacts and benefits
of the introduction,
both short- and long-term.
Only then can we make informed decisions
about non-native species.