Residents living around Pine Lake in Sammamish are helping to remove an invasive species from their waters, all while helping out research.

Julian Olden, an associate professor at the University of Washington School of Aquatic and Fishery Sciences, will be continuing work with residents later this month to combat the Red Swamp Crayfish.

“These first non-native crayfish were found in Pine Lake in 2000,” Olden said. “Now it occupies about a dozen lakes in western Washington.”

The Red Swamp Crayfish, Procambarus clarkii, is also known as the Louisiana Crawfish or the Mudbug. Native to the Gulf Coast from Mexico to Florida, the species is often featured in Cajun cooking in the south-central United States.

Listed as a banned invasive species by the Washington Department of Fish and Wildlife, P.clarkii is considered vectors for parasites and diseases that can negatively impact native species. First recorded in September 2000, populations of P.clarkii have been found in lakes throughout King County since then. State fisheries officials believe that the species was introduced as bait fishing for largemouth bass.

Olden, who has been working at Pine Lake for the past eight years, says that the larger, meatier traits of P.clarkii that make it more attractive to fishermen as bait are what makes it so dangerous to the local ecosystem.

“They have impacts on fish and amphibians, they eat their eggs,” Olden said. “They can affect recreationally important fish like bass. They also outmuscle and outcompete the native crayfish for shelter and food.”

P.clarkii are readily identifiable by their rough carapace and dark red color.

On his web site, Olden invites anyone to actively trap crayfish to help reduce P.clarkii populations in Pine Lake, which Olden calls the “most infested lake in the state.” To date, since starting last year, volunteers have removed more than 4,000 of the crawfish from the lake, putting in more than 30,000 trapping hours.

“In two years of participating in this program, we have captured hundreds of red swamp crayfish, but only a handful of the native Signal Crayfish,” Pine Lake resident Doug Henderson said. “Although we do enjoy the occasional crayfish boil, and find it somewhat humorous to see so many crayfish that you can even catch them in the lawn, we are a little sad that we almost never see the native signal crayfish around our dock.”

While Olden prefers only Pine Lake-area residents volunteer, all volunteers must follow guidelines. Potential volunteers need to be registered with Olden. Volunteers must also record and submit data including size and gender of each individual animal removed.

While Henderson has a degree in biology and formerly worked in an aquatic toxicology lab, the effort to control the P.clarkii population has been “a great learning experience” for his daughter, Solana, a student at Creekside Elementary.

“We are interested in doing whatever we can to improve the water quality and habitat,” Henderson said.

Volunteers also must take care to separate out members of the native Signal Crayfish species, Pacifastacus leniusculus, identified by their smooth shells and brown carapace, with a white patch near the base of each claw.

Any caught P.clarkii individuals can be disposed of or cooked and eaten. The state fisheries department requires that all captured animals not be re-introduced to the water, but killed and disposed of.

“A few times each summer we’ve hosted a crayfish boil with friends and family,” Henderson said. “When cooking them, we like to boil them in an outdoor cooker with potatoes, corn, sausage, onions, lemons, and Zatarain’s crayfish boil.”

For more information or to register as a volunteer, visit the project web site at depts.washington.edu/oldenlab/pine-lake.