OLYMPIA – Scientists have confirmed that Capitol Lake in Olympia is infested with aquatic invasive New Zealand mudsnails, prompting state agencies to seek the public’s help in containing the destructive invaders.
The state Department of General Administration, which manages the 260-acre lake, has temporarily closed all three boat-launch areas until further notice. Signs have also been posted asking visitors to stay off the lake to avoid spreading the destructive snails to other waters.
The Washington Department of Fish and Wildlife (WDFW), which is leading the state’s response, agreed that a temporary closure is needed to help prevent further spread of the snails while research continues to assess how best to deal with the infestation.
Officials from both agencies will be available at the lake from noon until 2 p.m. tomorrow (Nov. 25) to answer questions from the public and display New Zealand mudsnails found in the lake. The event will be held in Heritage Park near the Water Street entrance to the lower basin of the lake.
Allen Pleus, WDFW aquatic invasive species coordinator, said less is known about the destructive potential of New Zealand mudsnails than about such species as zebra and quagga mussels, which cause millions of dollars in damage in other states each year.
“But we do know that these mudsnails multiply quickly and can crowd out native species,” said Allen Pleus, “Our immediate focus is on containing the current infestation and determining the full extent of infestation. Then we’ll explore our options for controlling or eradicating it.”
Measuring just an eighth of an inch, New Zealand mudsnails have also been detected in freshwater canals on the Long Beach Peninsula and in the lower portion of the Columbia River. They can live in either fresh or brackish water and can reproduce asexually, so it only takes one mudsnail to introduce the species to a new area, Pleus said.
“These tiny snails can be transported in a pant cuff, on boots, kayak equipment or in your dog’s foot pads or fur,” he said. “That’s why we need the public’s support in preventing the problem from spreading to other waters.”
Olympian resident Bert Bartleson, president of the Pacific Northwest Shell Club, discovered the first evidence that mudsnails had reached Capitol Lake during a bird-watching trip there last month. He found 16 tiny black shells inside a larger shell, and reported his suspicions to a snail expert who contacted the U.S. Fish and Wildlife Service and WDFW.
Two independent experts in invasive species confirmed this week that additional samples collected by WDFW around the lower basin of Capitol Lake are, in fact, New Zealand mudsnails.
“Thanks to Mr. Bartleson, we found we had a problem before it got worse,” Pleus said. “We may never know how the first mudsnail got to Capitol Lake, but it is critical that we determine how far the infestation has spread. “That’s the first step in containing and hopefully eradicating these invaders.”
In the coming weeks, Pleus said the department plans to look for signs of infestation in the upper basin of Capitol Lake, and in the Deschutes River, Percival Creek and Black Lake, which are all part of the same drainage system.
As leader of the state’s response to the infestation, WDFW is working in conjunction with the Washington Invasive Species Council, composed of state, federal and tribal agencies committed to cooperative efforts to address invasive species.
“This is a great example of citizens and agencies working together to find and rapidly respond to new invasions,” said Chris Christopher, chair of the Washington Invasive Species Council, which initiated the multi-agency response. “Without quick action, this invasive snail can overtake an area, causing damage to the environment and economy and possibly significant costs to prevent its spread.”
For more information about New Zealand mudsnails and photos of some found in Capitol Lake, see WDFW’s website at http://wdfw.wa.gov/fish/ans.