They’re smaller than grains of rice, but these pests could end recreation in Lake Padden

Students study threat from invasive New Zealand Mudsnails

Young scientist from Salish Middle School in Lacey explore the impact of invasive New Zealand Mudsnails in Capital Lake
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Young scientist from Salish Middle School in Lacey explore the impact of invasive New Zealand Mudsnails in Capital Lake

Lake Padden could be closed to recreation if the spread of a dark snail that’s smaller than a grain of rice can’t be contained, the Bellingham Parks and Recreation Department warned.

The New Zealand mudsnail is an invasive species that’s been found on Lake Padden’s northwest side, which is a popular access point for swimming, casual fishing and boating at the park, the Parks Department said in a news release.

The non-native snails could wreak havoc on the lake’s ecology — and those of other waterways if they spread beyond Padden — as well as recreation there.

New Zealand mudsnails are usually light to dark brown, although they can look black when wet. They have five or six whorls. They multiply rapidly, generally by self-replicating. They are found in fresh and brackish water. They compete for food with native species, which they can crowd out.

They were found in Lake Padden in August 2018.

Why not just kill all of them? How to do that without harming other critical species isn’t yet known, parks officials said, so preventing their spread is the best approach for now.

That means, in the short term at least, that people visiting Lake Padden can expect some physical barriers between the shoreline and infested areas, and perhaps in the water as well.

The snails’ presence is affecting lake use in other ways.

The starting line for the swimming leg of the Lake Padden Triathlon, which is on Saturday, June 22, has been moved slightly east of the infested area at the lake.

Other community programs, such as the Jan. 1 Polar Dip, also could be affected.

This year’s frigid dip at Lake Padden was moved east of the infested area, but because a greater number of people who show up — and, therefore, spread out — than a triathlon, the New Year’s Day event could be moved to Bloedel Donovan Park, according to Melissa Bianconi, recreation manager for the Parks Department.

But the decision about a possible move for the Polar Dip hasn’t been made yet, she told The Bellingham Herald.

What is known is what can be done now.

The Parks Department said people who play in the lake must take the following steps to keep New Zealand mudsnails from spreading into other parts of Lake Padden and other water bodies in Whatcom County:

Wash well all gear after each use in the lake. It’s especially important to do so for footwear.

Put shoes in a freezer for 48 hours to kill off snails that may have hitch-hiked home on your stuff.

If possible, have gear that is used just at Lake Padden.

Keep your dogs out of the water in areas that have been posted because they can carry and spread the snails on their paws or hair. Wash your pet if it goes into the water.

“We need everybody’s help on this one,” Bianconi said. “It would be devastating if the lake had to be closed to recreational use.”

Staff from the city’s Aquatic Invasive Species program will be at Lake Padden this summer to share information with the lake’s users about the snails and what they can do to stop their spread.

The city also might install a wash station so people can decontaminate their gear before leaving Lake Padden, according to Teagan Ward, the Aquatic Invasive Species program coordinator.

Fish & Game fishery biologists show anglers how to slow the spread of New Zealand mudsnails in Idaho. The invasive species harms fisheries.

Kie Relyea has been a reporter at The Bellingham Herald since 1997 and currently writes about social services and recreation in Whatcom County. She started her career in 1991 as a reporter and editor in Northern California.