Invasive Species

New Zealand Mudsnails

New Zealand Mudsnails (NZMS) were recently discovered in High School Creek in North Redmond.  New Zealand Mudsnails are tiny (less than 6 mm) invasive aquatic snails that can completely cover stream and lake beds, pipes, and ditches.  

These tiny snails do not harm people or pets. However, once these hardy invaders spread across streams and lakes, on rocks, and in the mud, they crowd out native aquatic snails, insects, and plants that resident fish and other critters depend on.  NZMS provide no nutritional value to the salmon and trout that eat them.  They adapt to a wide range of environmental conditions.  This makes them hard to control and almost impossible to eliminate from our waterways.      

You Can Help Reduce the Spread of New Zealand Mudsnails!

NZMS can hitch a ride on boots, clothes, animal fur, and equipment and be carried by streams and stormwater to new locations. Mudsnails are tiny and easily mistaken for a small pebble.

Please take these steps to help stop the spread of NZMS in High School Creek and across Redmond:

1.  Keep pets out of streams and lakes.  If your dog wades into the water, carefully dry off or brush him/her on dry land.  Focus on paws and bellies.
2. Carefully scrub off any debris or mud from waders, boots or clothing that come in contact with streams, lakes or mud.  Freeze these items overnight…or let them dry out for 48 hours.  NZMS can survive out of the water for weeks.
3.  Drain-off any stream or lake water collected in gear or equipment before you leave a site.  Rinse off the gear in clean, potable water away from the body of water and let it dry for 48 hours before reuse.  Do not flush rinse water down the storm drain—it’s connected to our creeks, too, and can reintroduce mud snails!

Noxious weeds

Noxious weeds are introduced plant species that harm the environment and agricultural production and increase maintenance work at city facilities and projects. Many noxious weeds proliferate because they grow fast, out-compete native vegetation, and don’t have natural enemies to keep them in check. Once established, noxious weeds are challenging to eradicate and can harm wildlife and natural areas like stream buffers, wetlands, and forests.

The City uses an Integrated Pest Management (IPM) plan to prioritize using non-chemical control methods over pesticides while managing noxious weeds. Methods like manual, mechanical, and cultural control can be combined to control noxious weeds without harming the environment. 

King County’s noxious weed program is an excellent resource for the latest information on noxious weeds, including identifying and controlling them. 

Noxious weeds in King County, Washington - King County (link)

African Clawed Frog

African clawed frogs harm sensitive ecosystems by preying on native species and introducing pathogens that can harm native amphibians and fish. They have recently been found in neighboring cities like Issaquah and Bothell. They were likely introduced by people dumping their pets into local ponds. African clawed frogs are a prohibited species. Please report potential sightings to the Washington Invasive Species Council at invasivespecies.wa.gov