A Chinese mystery snail — also known as Asian apple snail, Asian freshwater snail and trapdoor snail — rests off the boat launch at Six Mile Lake in northern Dickinson County. Chinese mystery snails are known locally to be in Lake Antoine, Cowboy Lake and Crystal Lake, as well as spots along the Menominee River, according to Lindsay Peterson, coordinator for the Wild Rivers Invasive Species Coalition. (Betsy Bloom/Daily News photo)

Can a snail native to the Far East manage to establish itself in the Upper Peninsula?

Yup — but, being a snail, only with some significant human help.

Wednesday, while trying to photograph butterflies and dragonflies that have emerged this spring, I spotted something just off the boat launch at Six Mile Lake — a snail roughly the size of a ping-pong ball, much larger than any I’d seen before, even as an empty shell. But this one was very much moving.

Most of the lake’s snails have a ram’s horn shape as well, while this one was more rounded.

My first thought was apple snail — and invasive.

That proved to be sort of right.

Jennifer Johnson, fisheries biologist at the Michigan Department of Natural Resources’ Crystal Falls office, identified it as a Chinese mystery snail, also known as Asian apple snail, Asian freshwater snail and trapdoor snail.

It’s had a long time to make its way across North America. Chinese mystery snails are thought to have first been introduced as a food item for Asian markets in California in 1892, according to the Smithsonian Institution.

“By 1911, they were established in freshwater sites between San Jose and San Francisco, and were collected in the estuarine Sacramento-San Joaquin Delta by 1938 (Cohen and Carlton 1995),” the Smithsonian Institution’s website on the species states.

It was part of the pet trade, too, sold as a large, attractive snail for aquariums and garden ponds or unknowingly carried in on aquatic plants.

By 1914, it had reached Boston and the East Coast, probably from goldfish or other aquarium releases, according to the Smithsonian site. It was first recorded in the eastern Great Lakes-St. Lawrence River basin in the Niagara River in 1931 and became well established by 1942.

In the upper Great Lakes, this snail has been collected in Green Bay, Wis., on Lake Michigan (Dundee 1974) and at the mouth of the Thunder Bay River in Alpena, Michigan (USGS Nonindigenous Aquatic Species Program 2010).

It can grow to more than 2 inches across and live for three to five years. It feeds on algae and prefers soft-bottomed freshwater bodies that are not brackish.

The Chinese mystery snail is unusual as well in that it broods its eggs internally, continuously releasing small numbers of live, fully formed juveniles during the warmer months. Females reportedly can produce about 65 offspring per year.

Its ability to seal the shell opening with a plate called an operculum — hence the trapdoor name — means it can survive out of water for days, sometimes weeks, without drying out.

Which is how boaters can unwittingly transfer them among water bodies.

This invasive species can now be found throughout much of Wisconsin, where it’s been recorded since the 1950s.

Chinese mystery snails are known locally to be in Lake Antoine, Cowboy Lake and Crystal Lake, as well as spots along the Menominee River, said Lindsay Peterson, coordinator for the Wild Rivers Invasive Species Coalition, the multi-partner organization based in Kingsford that works to manage invasive species in five counties in Michigan and Wisconsin. They’re thought to be in Bass Lake and likely in the Groveland Mines ponds as well, she said.

This sounded like the first confirmation of the snail at Six Mile Lake, but it tends to be underreported in Michigan, which doesn’t rank it as a high priority on the invasive watch list, Peterson said.

That’s because as invasives go, the Chinese mystery snail isn’t that bad. It’s not thought to harm fisheries or have as devastating an effect on the aquatic environment as several other invasive species.

That’s not to say it’s great to have them — they may outcompete native snails and they are “prone to great population booms and busts,” according to the Smithsonian website. Other sites describe mass die-offs that leave beaches and shorelines covered with foul-smelling shells.

Snails also can carry parasites — Peterson said lakes with mystery snails “often see higher or more frequent occurrences of swimmer’s itch later in the summer.” Swimmer’s itch is caused by a fluke larvae that lives in waterfowl and snails.

Still, as invasive species go, the Chinese mystery snail has been around for many decades without causing major problems, like zebra mussels and emerald ash borers, where it turns up.

“Mystery snails kind of level out in time,” Peterson said.

But its presence in the region demonstrates how easily invasive species can be spread when proper practices are not followed with watercraft — what Peterson referred to as “Clean Drain Dry.”

This recommends that when leaving any water body, equipment and boat hulls be rinsed and motors be flushed, preferably with hot water when possible; motors, bilge, livewell and other water-containing devices be drained; and everything be dried for at least five days or wiped before leaving the water access. Anglers are asked to add Dispose to the list, by putting unwanted bait, worms and fish parts in the trash rather than dumping them into a water body.

“The prevention steps are pretty easy to follow,” Peterson said, later adding, “Keeping things out is a lot easier to manage than dealing with it once it’s there.”

She concluded, “One time it might be a mystery snail (that’s carried in). Next time it might be watermilfoil or VHS, a fish disease.”

Betsy Bloom can be reached at 906-774-2772, ext. 240, or bbloom@ironmountaindailynews.com.