Huntsville has a new, and unwelcome, resident in its waterways.
Doppler reader David Wexler sent in a photo of a pair of aquatic snails he found near Camp Kitchen, where the Muskoka River flows into Fairy Lake, wondering if they might be an invasive species.
Brook Schryer, aquatic program specialist with Ontario’s Invading Species Awareness Program, confirmed that the snails are Chinese mysterysnails (Cipangopaludina chinensis), one of three invasive snail species in Ontario—the other two are the banded mysterysnail and the New Zealand mudsnail.
Chinese mysterysnails have been in North America for more than a century, having been shipped to California in the late 1800s for Asian seafood markets. They were likely released into the Niagara River from aquaria in the 1930s, and can be found there to this day. According to the program’s website, the Chinese mysterysnail has also been found in Lake Ontario, Lake Erie, Kawartha Lakes, Trent River drainages, and the Crowe and Moira River watershed.
Until this year, they hadn’t been reported in the Huntsville area. In May, the program received a report of five of the snails in Palette Lake, north of Huntsville. And now these two found by Wexler.
That makes their presence here a relatively new expansion, said Schryer, but as an aquatic species—which can make them more difficult to detect in early stages of an expansion, particularly when they are adolescents—it’s unknown exactly when they first arrived. And because of the difficulty in detecting them, they can be near impossible to eradicate once they’re in an area.
Now that they are here, they could have a variety of impacts.
They can compete with native species for food. These snails are planktivores—they, like their fellow invasive species, zebra mussels—feed on the plankton in the water and reduce its availability for other species. They also feed on algae.
That reduction in plankton can also lead to clearer water, which at first might seem to be a good thing. But clearer water lets more sunlight in which can encourage aquatic plant growth, perhaps in itself an invasive species. That growth can then form a dense monoculture of that plant species, which “makes recreating [in that spot]impossible,” said Schryer.
Also of concern is the parasites the snails may carry which can lead to the death of waterfowl.
And they are prolific reproducers—within her five to six-year lifespan, a female can produce about 400 offspring which are birthed live, rather than as eggs, giving the species an advantage over other egg-laying species. When there is a mass die-off within a population, which sometimes happens in the spring or summer, hundreds can wash up on shore at a time—and that stinks, literally, for any property owner.
The best thing you can do to help slow their spread is to first learn to identify them—they can sometimes be confused with native species like the great pond snail, and knowing the difference can keep a native snail from meeting an early demise. A Chinese mysterysnail is less than 6.5 cm in length and brownish to olive-green in colour. An adult’s shell has six to seven whorls, and a live Chinese mysterysnail will have an operculum—the ‘trap door’ that allows the snail to close itself within its shell.
Then, if you think you’ve found one, take a photo and report it to the invading species hotline at 1-800-563-7711 from Monday to Friday, or anytime online at eddmaps.org/ontario. Specialists will confirm if you’ve found an invasive species, and direct you what to do with it. They will also inform the Ministry of Natural Resources and Forestry if it’s been found in a new area.
Once you’ve confirmed the species, if the snails are already dead you can bury them on your property. If they are alive, you can place them in a resealable plastic bag and place them in your freezer for four to six hours to humanely euthanize them and then bury them. They can also be sealed in a bag and placed in the garbage, but as a landfill is not a good place for organic matter, that should be your second choice.
To generally help prevent their spread, ensure that you clean, drain, and dry your boat. And never release any animals from your aquarium into local waterways.
For more information on invasive species in Ontario, visit invadingspecies.com.
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