California Officials Detect Invasive Mudsnails in Lake Tahoe

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Why it matters: The species are known to displace native snails and disrupt the food chain for trout and salmon. Additionally, the snails can reproduce at alarmingly fast rates in warm freshwaters.

A single female can reproduce itself 230 times a year, and according to Tahoe Regional Planning Agency information officer Jeff Cowen, divers in the Great Lakes have found as many as 500,000 individual snails in a single square meter. That's about 10 square feet.

The backstory: New Zealand mudsnails were first found in Idaho’s Snake River in the late 1980s and have since spread to 22 other states. California first detected them in the Owens River in 2000.

It’s not known exactly where they came from, but scientists theorize that mudsnails were introduced to western rivers through shipments of live sport fish. Since then, they’ve been hitching rides on fishing equipment, shoes, and even in clothing. The mudsnails tend to be smaller than a grain of rice and are difficult to spot with the naked eye.

What's next: Scientists and divers working at the Tahoe Regional Planning Agency need to conduct further dives to determine the severity of the infestation. One major issue is that the snails lack natural predators in the United States.

The best method to scale back the population is containment. The snails spread to other bodies of water by attaching themselves to aquatic gear and clothing, but they don’t do well in freezing or hot temperatures. Leaving items to dry out in very cold or very hot weather should be enough to kill traveling snails and decontaminate personal belongings.

As for Lake Tahoe and the many other bodies of water populated with the mudsnails, scientists are working on ways to contain their spread, but it may be impossible to eliminate them completely.

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