An invasive species is putting other creatures at risk

As our Earth’s climate changes, consequences are playing out in some surprising ways. At Crater Lake National Park in Oregon, surface water temperature is on the rise to the benefit of an invasive crayfish that is putting the lake’s clarity and native creatures in jeopardy.

TRANSCRIPT

As our earth's climate changes, consequences are playing out in some surprising ways.

At Crater Lake National Park in Oregon, surface water temperature is on the rise, to the benefit of an invasive crayfish that is putting the lake's clarity and native creatures in jeopardy.

Our environmental news partner, EarthFix, has this report.

Good candidate... but no salamander.

Biologist Mark Buktenica is scouring the shoreline of Crater Lake.

Flying ants, lizards, and small toads are everywhere.

Aren't they cute?

But the critter he's looking for is much more elusive.

Then, his persistence pays off.

Oh!

This is the Mazama newt.

The Mazama newt, found no place else in the world.

Crater Lake formed nearly 8,000 years ago, after Mount Mazama erupted and the caldera began filling with rainwater.

We don't know when newts entered the caldera, but sometime thousands of years ago.

There were no fish or other predators in the newly formed lake, and the Mazama newt expanded and thrived.

He's playing dead on us now.

It was the undisputed top of the food chain.

But not anymore.

Because crawling beneath the surface of the lake, a new champion has emerged -- the signal crayfish.

Their story begins more than 100 years ago, back when getting to Crater Lake from Medford took five days by horse and wagon.

To attract visitors, early conservationists began stocking the lake with game fish like trout and salmon.

Craig Ackerman is park superintendent.

In the past, the National Parks have done many things which people thought were good ideas at the time that turned out to be not so great ideas.

In 1915, park managers introduced the signal crayfish to feed those fish.

And that turned out to be a worse decision than stocking the fish in the first place because the crayfish have become out of control.

And this is obvious out in the lake.

Scientists at the park are finding that crayfish and the Mazama newts don't really get along.

Bloop!

They're at a standoff.

What's gonna happen?

Not only do they compete for the same food, but studies done by park biologists show crayfish chase and harass the newts...

[ Gasps ]

...causing them to flee...

They're almost like pack-hunting a little.

...and, in some case, much worse.

They're virtually the perfect invader.

The Mazama newt, on the other hand, is an ideal prey.

After thousands of years evolving without predators, the newt lost its best weapon -- a potent neurotoxin that can kill.

With the loss of its toxicity, it's left virtually defenseless.

But actually, crayfish in Crater Lake weren't thought to be such a problem until relatively recently.

Surveying started in 2008, and scientists found newts had the advantage, occupying about half the shoreline.

The crayfish had most of the rest.

By 2014, the crayfish had taken over 75% of the shallows.

It's right here, Scott.

And that's not all, says biologist John Umek.

Got it.

Big bag for this one.

Crayfish are impacting all the organisms in the near shore, not only newts.

In crayfish areas, we don't find snails.

You have to go outside of the crayfish-dominated areas to even find a snail or two.

Instead of this great biodiversity area, it's down to one or two organisms and that's it, besides crayfish.

Without these tiny organisms eating the algae, the crystal blue clarity of Crater Lake could be at risk.

Crater Lake biologist Scott Girdner suspects that climate change is playing a role.

Four in 'A'.

The surface temperature of the lake has increased about three degrees in the past 10 to 15 years.

And it may just allow the crayfish to move faster.

They just are more active at warmer waters, and it may allow them to have more success at reproduction so that their numbers have increased faster now.

The team surveys for crayfish each summer.

Surface.

Oh, my gosh.

That's a lot of crayfish.

They set traps all along the shore and deep into the lake.

Six.

They count, weigh, and measure their catch.

38.55.

And they tag and release some to find out how they travel.

They've even found crayfish at 750 feet.

Look at that. That's amazing.

Deepest-known crayfish in any lake system.

What are they doing at 250 meters?

Scientists expect that if crayfish continue to spread...

It's very possible that the Mazama newt would be eliminated from the lake if we didn't do anything.

But at this point, no one knows exactly what to do.

Trapping, even intensive trapping, hasn't made a dent.

Yet there are a few glimmers of hope for the Mazama newt.

There's the possibility of building underwater barriers or fences to slow crayfish expansion.

Another solution could be provided by the lake itself.

Spring-fed pools like this emerge when avalanches pile up rock berms along the shore.

These pools are newt nurseries.

They'll come into these pools while there's still snow on the edges of the pool.

The conservation promise is that while newts move across land to get to the isolated pools, signal crayfish do not.

If other strategies to stop the spread of the crayfish aren't effective, these pools could become a final stronghold for the Mazama newt and other native animals.

We have the opportunity right now to at least slow down the invasion of crayfish.

If we miss this opportunity, I think it's gonna be a lot of trouble for the newts.

Without intervention, this unique creature could vanish from the lake within the next few decades.

Controlling the signal crayfish and protecting this unique ecosystem will be labor-intensive and expensive.

But the park service's mission and mandate is to do this above all else.

So we will put the resources into this that we feel necessary.

The sobering reality is crayfish will likely never be eliminated from Crater Lake.

Come on, little guy.

And maybe the best the National Park can hope to do is carve out a few safe havens for the Mazama newt.