Possibly due to summer’s hot and dry weather, snails were prevalent in the finds of Starry Trek participants in the Aitkin area Aug. 21.
Seven volunteers turned out for the local event, splitting into three teams, visiting 10 lakes. The day included instruction on aquatic vegetation, what to look for and how to sample. If volunteers found anything they felt was unusual or suspicious, they collected a sample and brought it back to the starting point, which was Ripple Lake.
The event was led by Penny Stiles, aquatic invasive species detector and Master Naturalist and Janet Smude, district technician with the Aitkin County Soil and Water Conservation District. Stiles and Smude inspected an additional six area lakes.
Confirmation of identities came from a DNR aquatic invasive species specialist. The group found banded mystery snails in Cedar Lake. Common waterweed, a native species, was collected in Hammal Lake. Plants identified from Sugar Lake were also native aquatic plants.
According to Meghan Weber of the Minnesota Aquatic Invasive Species Research Center, 206 people joined the statewide Starry Trek this year.
“Participants searched a total of 281 public accesses on 222 water bodies,” she reported. “No new starry stonewort discoveries were made this year.”
“Each year we also get several new reports of Chinese and banded mystery snails that were not yet in the nationwide invasive species reporting system,” noted Weber. “Not all of these are previously unknown populations, however, many of these helped update the database, which is used by DNR and many other agencies to track populations of invasive species so their discovery and reporting is still important and beneficial. And some are likely the first time that species has been reported in that water body.”
WHAT ARE THEY?
Banded mystery snails are small animals with a coiled spiral shell. They grow up to one and one half inches and are light brown with red/brown horizontal bands that follow the spiral of the shell.
The shell opening is on the right when the shell is pointed up. They have an operculum (trap door) covering the opening, which is missing when the snail is dead or the shell is empty.
The banded mystery snail grazes and filter-feeds on dead organic matter typically on silt and mud substrates. They are called “mystery” snails because females give birth to young, fully developed snails that suddenly and “mysteriously” appear. Their lifespan is about four years. Banded mystery snails can cause mortality of largemouth bass embryos by invading bass nests and can die off in large numbers, fouling beaches and shore land.
People spread these snails mostly through movement of water-related equipment and illegal release of aquarium pets. It is illegal to release or dispose of unwanted aquatic plants or animals in or near public waters.
Lookalikes to the banded mystery snail are: Chinese mystery snails, faucet snails and New Zealand mudsnails – all invasive species. There are also a number of snail species native to Minnesota.
As always, stopping the spread of invasive species to other lakes and rivers protects habitat for native species such as sunfish and crappies. Overall lake and river health is better without invasive species. Healthy lakes and rivers benefit fish, wildlife and people. Remember, “Clean, drain, dry and dispose.”