Environment | Education | Oregon

Invasive Crayfish May Be Class Pets First

OPB | Feb. 16, 2011 10 p.m. | Updated: July 17, 2012 1:05 a.m. | Corvallis, OR

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Oregon has two new invasive species to deal with. For the first time in the western United States, scientists say two kinds of crayfish have appeared in streams and rivers.

What makes this story unusual is how they got here. Oregon Field Guide’s Vince Patton reports that it’s probably not anglers or boats spreading the crayfish. Instead, it may be your children.


This is a story of a river in eastern Oregon, a stream in the Willamette Valley and a pest.

Rusty Crayfish

Vince Patton / OPB

The invader they share in common got a helping hand from the most unlikely people.

Let’s start on the John Day River.

Julian Olden and a colleague are wrestling with a wide flat net.

They struggle to pull it down to the bottom of the riverbed.

Once it’s there, they shuffle their feet.

Within seconds they kick up what they’re looking for.

Julian Olden: “They’re pretty thick through here. Take a couple of kicks. It’s pretty much a crayfish under every rock. That’s the reality of it.”

Olden is an assistant professor with the University of Washington.

He’s finding rusty crayfish throughout 30 miles of river stretching downstream from the town of John Day.
They don’t belong here.

Julian Olden: “This is the first known population west of the Continental Divide. This species are native to the upper Ohio River drainage in the Midwestern U.S.

It turns out the John Day isn’t the only new Oregon home for invasive crayfish.

There’s a small stream gurgling through Corvallis called Dixon Creek.

It also has rusty crayfish from the Midwest, plus Red Swamp crayfish from Louisiana.

So how do 2-inch long crustaceans climb the Rocky Mountains to reach the John Day River and then hike again over the Cascade Range to the Willamette Valley?

Anglers and their boats often introduce invasive species to new waters.

But they’re not the likely carriers this time.

Scientists realized that both the John Day River and Dixon Creek run behind several grade schools, which buy science kits that contain live crayfish.

Julian Olden:”Unlike the dominant vector which is through bait bucket releases of fishermen, we see a quite different story here.  Crayfish are using the classroom.”

Every year, children at Franklin School in Corvallis get a hands-on lesson in biology. They feed and study live crayfish.

Their teacher, Jennifer England, says there’s no better way to engage kids than by having living examples in the classroom.

Jennifer England:  “You can talk about it, you can look at a movie but it’s not the same as actually picking it up and learning how to, to hold the crayfish and what are the structures and how really unique are they.” 

It’s when the lessons end that they cause problems.

Gregory Murphy studied crayfish for a whole semester.

Gregory Murphy: “And what happens in the classroom is people don’t know what to do with them so they’ll just release them into the wild and they won’t know they’re actually making an impact ecosystem.”

You see, Oregon has only one native crayfish. It’s called the signal crayfish.

Murphy has learned the signal doesn’t have a chance when aggressive crayfish from other parts of the country show up in local waters.

Gregory Murphy: “They will um, eat the fish eggs that are in the rivers and they will also kick the native crayfish out of their habitats.” 

The Oregon Department of Fish & Wildlife says shipping invasive crayfish into Oregon is illegal.

It sent warning letters in 2008 to a couple of suppliers who ship live crayfish, frogs and turtles to individuals and classrooms.

The shipments continued. One of those firms, Ward’s Natural Science, says it includes a warning in every shipment to, quote “never release a live laboratory organism into the wild.”

ODFW chose not to aggressively enforce the law.

Instead, the agency says it favors the approach Sam Chan is taking. He’s with Oregon Sea Grant and he’s teaching teachers to make the crayfish part of a lesson on invasive species. 

Sam Chan: “Teachers are using this as a teachable moment and their students are learning about invasive species while learning about science.”

So the most important thing is for us not to be releasing live plants and animals from classrooms.” 

Some schools are sending their crayfish to Chan at OSU at the end of semester.

Others, like Franklin School, teach kids that the best option may well be euthanasia.

That’s what they opted for in Gregory Murphy’s class.

Gregory Murphy: “We actually put them in a bag and put them in a freezer. And that was a very painless way for them to go.”

Oregon Sea Grant would like to spread the lesson beyond Oregon.

It’s estimated that 25 percent of the elementary schools in the nation receive crayfish for their science classes.


Aquatic Invasive Species Toolkit

Invasive Species 101

Crayfish Identification

Eastern Oregon Invasive Species  

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