Self-Cloning Invasive Snails Found in Popular U.S. Lake for the First Time

New Zealand mudsnails, tiny invaders that clone themselves and outcompete native species, have been confirmed in Carter Lake in Northern Colorado. Officials say they’re nearly impossible to remove.

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New Zealand mudsnails, an invasive species, were confirmed in Carter Lake in Northern Colorado for the first time

The snails disrupt ecosystems by consuming nutrients and outcompeting native species but pose no risk to human health

Officials are focused on preventing their spread as the snails can clone themselves and survive on damp gear for weeks

A tiny, self-cloning invasive snail has been confirmed in a Northern Colorado lake, and once the species moves in, it’s nearly impossible to eradicate.

Colorado Parks and Wildlife (CPW) confirmed the presence of New Zealand mudsnails in Carter Lake, southwest of Loveland, Colo., according to CBS News Colorado, marking the first time the species has been found in the popular reservoir. The agency is now focused on keeping the snails from spreading to other waterways in Larimer County.

New Zealand mudsnails are small, brown creatures that consume large amounts of nutrients in an ecosystem and compete with native species for food. “These mud snails are very big eaters, and they just kind of go through all of the different nutrients that are in an ecosystem and don’t really provide any benefits back to anything else in there,” CPW spokesperson Kara Van Hoose told the outlet.

Van Hoose said the snails don’t pose a risk to human health, but can severely disrupt aquatic ecosystems. “They are not good food for fish. They can pass right through birds that eat them and then come out unscathed,” she explained. “Instead, they just eat, and eat, and eat, and sap all of the nutrients and outcompete our native species for food.”

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Part of what makes them so hard to control is how they reproduce. According to officials, the snails can clone themselves, meaning a single individual can launch a new infestation.

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In the western U.S., all New Zealand mudsnails are female, and each is born already carrying embryos, as recorded by the National Park Service. Populations can reach densities of hundreds of thousands of snails per square meter. Their dense numbers can also clog reservoir inlets, outlets, and recreational structures.

The discovery at Carter Lake is the latest example of the species turning up in Colorado. Van Hoose noted that the snails have been confirmed in 41 other bodies of water across the state.

At Carter Lake, boat inspection checkpoints now look for mudsnails in addition to other invasive species, such as zebra mussels.

CPW officials say the snails are likely to remain at Carter Lake because of how easily they reproduce, so the agency’s focus now is to prevent them from being transported elsewhere.

The snails can survive for days out of water and for weeks on damp gear, so officials urge boaters and swimmers to clean, drain and dry all equipment before using it in another body of water.

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