A new threat emerges in Lake Lanier: Invasive ‘mystery snails’

The snails are known to harbor parasites, posing a risk to native species and potentially human health
Invasive Chinese and Japanese mystery snails have been found in Lake Lanier, Georgia wildlife officials say, posing threats to humans and native wildlife.

Credit: Courtesy photo

Credit: Courtesy photo

Invasive Chinese and Japanese mystery snails have been found in Lake Lanier, Georgia wildlife officials say, posing threats to humans and native wildlife.

From bee-eating hornets to carnivorous frogs, all manner of invasive plants and wildlife that don’t belong in Georgia have been introduced to the Peach State over the years, posing grave threats to native species.

Now, state wildlife officials are sounding the alarm about another unwanted creature that was recently discovered in the murky depths of Lake Lanier: “mystery snails.”

Mystery snails belong to the genus Cipangopaludina and are native to China, Japan and other countries in Asia, where they thrive in freshwater lakes and rice paddies. The “mystery” in the species’ common name is a nod to their strange life cycle: Each spring, after the creatures give birth, fully-developed young snails appear seemingly out of nowhere.

The snails, which can grow to be larger than a racquetball, have been in the U.S. for decades. Popular as food and in home aquariums, the Japanese variety was likely introduced in markets on the West Coast as early as the late 1800s, the U.S. Fish and Wildlife Service says.

Invasive mystery snails that were recently discovered in Lake Lanier could pose a threat to native species and human health, officials say.

Credit: Georgia Department of Natural Resources

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Credit: Georgia Department of Natural Resources

The gastropods were first spotted in California waterways back in 1911. In the years since, they have spread to lakes and rivers across the U.S., including in Georgia. The snails were first discovered in the wild in Georgia in the Upper Chattahoochee River back in 2013, according to the U.S. Geological Survey.

But their arrival in the state’s largest lake is a new and unwelcome development, officials with the Georgia Department of Natural Resources (DNR) say. The snails also appear to be reproducing in Lake Lanier, adding to the concern.

“While we initially hoped that this was an individual specimen found in (Lake) Lanier, further investigation indicated that this is a viable, reproducing population of snails,” Jim Page, an aquatic nuisance species coordinator with DNR, said in a statement.

In Georgia, it is now illegal to buy, sell or keep mystery snails as pets, after new bans on certain non-native species were phased in by state wildlife officials starting in late 2022.

Page said DNR does not know how the species arrived in Lake Lanier, but said their continued presence in certain food markets and aquariums in the U.S. could be to blame.

Growing one to three inches long, mystery snails are bigger than most gastropods found in Georgia and are distinguished by their large, brown shells, which grow darker with age.

The snails pose serious threats to ecosystems, property and potentially human health.

They are capable of explosive population growth, allowing them to outcompete native species and harming animals up the food chain, like snakes and waterfowl that eat snails.

Mystery snails are also known hosts for several parasites, including rat lungworm, a dangerous nematode that can infect humans and other wildlife species if consumed. While infections are typically mild, ingestion of the parasite can occasionally lead to a rare type of meningitis. The symptoms include headache, a stiff neck, tingling in the skin, fever, nausea, and vomiting, according to the Centers for Disease Control and Prevention.

The CDC says people who eat raw or undercooked snails or slugs can get infected with the rat lungworm. Also, the agency advises that people can be accidentally infected “by eating raw produce (such as lettuce) that contains a small slug or part of one.”

The snails are also known to cling to boat hulls, causing damage and potentially offering the hitchhiking species a free ride to new waterways.

At this point, it may not be realistic to eradicate the snails from Georgia’s lakes and rivers, but Page said the public can help prevent new introductions of the creatures by thoroughly cleaning boats, trailers and fishing equipment after outings. He also called on Georgians not to dump aquariums or release any other non-native species.

“Prevention continues to be our best tool in fighting the war on invasive species, and prevention is only achieved with the help of the public,” Page said.