Louisiana red swamp crayfish changes life in a Sammamish lake

By Sonia Krishnan

Seattle Times Eastside bureau

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STEVE RINGMAN / THE SEATTLE TIMES

Karl Mueller, a graduate student at Western Washington University, spends hours in Pine Lake watching how the Louisiana red swamp crayfish and the native signal crayfish interact.

Mueller says the Louisiana red swamp crayfish, above, is more aggressive than the native species.

Karl Mueller lowers an enclosure containing both species of crayfish into Pine Lake. The cage contains pieces of pipe that the crayfish use as shelter. Mueller learns about the species by watching what transpires between them in the enclosure Mueller chooses samples of each crayfish species from his holding table before putting them in the enclosures. The problem of the invasive crayfish in Sammamish's Pine Lake probably started innocently enough.

Perhaps a fisherman tossed his live bait in the water years ago. Or a child decided to set her aquarium creatures free.

However the Louisiana red swamp crayfish ended up in the lake, Karl Mueller is certain of one thing: They are overrunning the native signal crayfish at a fast clip.

And that shift is changing the entire freshwater ecosystem of the lake, he said.

"They've really done a number on it," Mueller said.

Mueller, a former biologist with the state Department of Fish and Wildlife, has been camped out at Pine Lake for several weeks observing the two species of crayfish duke it out for survival.

How to prevent the introduction of non-native species


If fishing with live bait, do not empty the contents in the water. Dispose in the garbage.

Find fish-rescue groups on the Internet that take unwanted aquarium animals. Or kill them humanely by freezing them in a plastic bag. Dispose of in the garbage.

Do not release live aquatic wildlife found at seafood markets or classroom biology labs into the water.

Remove any visible vegetation from boats after use.

The invasive Louisiana red swamp crayfish — which hail from the South and northeast Mexico — are outnumbering the native signal crayfish by a ratio of 3-1.

What this means is that the numbers of native crayfish could dramatically decline and might disappear, he said.

"In a larger sense, it's the homogenization of wildlife," Mueller said. "You could compare it to what's happening with retail in America. The same stores are everywhere now. In nature, you're not supposed to have that."

No agency tracks how many invasive species of crayfish inhabit lakes. But in King County, the Louisiana red swamp crayfish also has been recorded in Lake Washington and Steel Lake. Although considered a delicacy, red swamp crayfish are a prohibited species in Washington, meaning they must be killed before being transported.

Mueller, 44, discovered the red swamp species in Pine Lake six years ago when he was a state biologist. It was the first time the non-native species had been officially reported in Washington.

He later left the job to go back to school but could not get the critters out of his mind. What would happen if the red swamp crayfish were left to flourish? How would this affect the signal crayfish that had inhabited the lake for generations?

Now a graduate student at Western Washington University, Mueller is observing the ongoing turf battles between the signal and red swamp crayfish this summer as part of his master's thesis. He charts how the crayfish — burrowing creatures by nature — compete with each other for shelter.

Mueller has collected between 130 and 140 red swamp and signal crayfish from the lake and divided them into separate wire-mesh enclosures. The enclosures contain roughened pipe that the crayfish use as shelter.

On a warm morning last week, Mueller donned a snorkel mask and fins as he dunked in and out of the water, depositing the crayfish. He then placed the enclosures back into the water. Later, taking notes with a pencil on waterproof paper, he spent two to three hours kneeling in a dry suit at the bottom of Pine Lake watching the crayfish guard their shelter.

There's no doubt the red swamp crayfish are more aggressive, Mueller said. He's seen them kill and eat the signal but has never watched it happen the other way around. He has been bitten by red swamp crayfish more times than he can count, he said. Once, a red swamp latched onto a nerve on his finger with its pincers and wouldn't let go.

"They are really predator-savvy," he said.

The red swamp crayfish also reproduce more rapidly, producing double the eggs the signal produces.

"They are just plowing through food," Mueller said.

The rampant feeding and burrowing create a domino effect in the lake. The activity releases nutrients such as phosphorus into the water, which leads to more algae bloom, which could suffocate the lake.

"Up, down, across, it's all affected. It's all connected," he said.

Pam Meacham, acting aquatic invasive species coordinator for the state Department of Fish and Wildlife, said what's happening at Pine Lake epitomizes how one small action can wreak environmental havoc.

"People have this bad habit where they get tired of their aquarium or goldfish bowl and dump them in the nearest pond or lake," Meacham said.

"But that 10-cent goldfish can get to be about 2 feet. This agency has literally removed truckloads of goldfish out of Newman Lake in Spokane."

Fisheries biologists with the U.S. Fish and Wildlife Service said Mueller's research will be valuable if the signal crayfish ever are designated endangered species.

As far as Mueller can tell, the red swamp crayfish are here to stay.

So now it becomes a matter of making sure the problem doesn't get worse, he said, by keeping the invasive crayfish out of other bodies of water.

"The ticket is trying to prevent further introductions," he said.

Sonia Krishnan: 206-515-5546 or skrishnan@seattletimes.com

Heh heh, what's the problem ya'll?

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You don't need a weatherman to know which way the wind blows - Robert A. Zimmerman

Dem damn northerners it's "Crawfish" not Crayfish and there would not be a problem if they would just learn to eat them crawfish

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Keith Schuster
2006 E350 98K miles
2013 Ford Explorer 15K miles

Down to Charlottesville we called'em crawdads.

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Yea after many, many , many beers we get to that pronuciation or worse

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Keith Schuster
2006 E350 98K miles
2013 Ford Explorer 15K miles

Mud bugs.

Is this some kind of commentary on the immigration problem?

Bot, how are they in Jambalaya? Or is it gumbo?

On a more serious note I have had the thought many times that environmentalists view human beings as being external to the rest of the ecosystem. It's as though they think we are on the outside, tinkering with and screwing up the environment rather than actually being a part of it ourselves.

Nature has a way of dealing with imbalances as I am sure you know better than I do. Whether it is disease, war, or some other phenomenon, nature seems to correct things when they get out of control or outlive their usefulness.

Have you all had problems with the Aisian Snake Head fish down there in LA? It has been a real problem up here in the Chesapeak Bay Area. Another situation in which people are throwing their unwanted pets into the river.

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" We have nothing to fear but the main stream media itself . . . ."- Adapted from Franklin D Roosevelt for the 21st century

OBK #55

1998 Lincoln Continental - Sold
Max 1984 300TD 285,000 miles - Sold
The Dee8gonator 1987 560SEC 196,000 miles - Sold
Orgasmatron - 2006 CLS500 90,000 miles
2002 C320 Wagon 122,000 miles
2016 AMG GTS 12,000 miles

Philosophical argument, that. The extreme arguments are interesting--in which man, derived without the hand of God, is an integral part of nature and therefore, can do nothing unnatural. Or Man, a special creation of God, is charged by God to be a good steward of the environment. These arguments turn the traditional liberal vs conservative political arguments on tehir head, if one supposes that Biblical literalists are conservative and evolutionists are liberal.

It's strange.

B

Actually their very good in both...besides boiling them, I like them are best in a pie.

I have not heard of that fish in our waters yet.....we do have the Zebra Mussel showing up now. It is not a huge problem yet but getting worse with time.

__________________
Keith Schuster
2006 E350 98K miles
2013 Ford Explorer 15K miles