Thursday, April 20, 2017

Emerging Concerns Over Banded Mystery Snails

Banded Mystery SnailThe warming temperatures and receding ice are giving way to open water and increased recreational activities. It is time once again to think about aquatic invasive species. An emerging threat to our fish populations and bird populations is the Banded Mystery Snail.

The Banded Mystery Snail (Viviparus georgianus) a non-native species to the Adirondacks was introduced in 1867 into the Hudson River. It is historically native to Florida and Georgia among other southeastern states. It has been found in many bodies of water located within New York, including Lake Champlain and Lake George. The public, officials and scientists have not taken much note of this non-native species believing that any environmental impacts would be negligible. Current data is showcasing a different picture and further research is needed.

The Banded Mystery Snail competes with native snails and mussels for both food and habitat. It forms dense populations that cover the substrate. They have a 40% greater survival rate of young then native snails, giving them a competitive advantage. They produce multiple generations of live (born not hatched) young. They can survive out of water for days, making eradication nearly impossible. The Banded Mystery Snail overwinters in deeper parts of the water then migrates to shallow, warmer water where live birth takes place. When they die, the shells wash up on beaches, clog intake pipes and could hinder recreation and decrease property values.

The Banded Mystery Snail serves as a host for parasites that can impact both wildlife and humans. Large waterfowl deaths in the upper mid-west have been linked to the Banded Mystery Snail as the intermediate host for the trematode worm. This is of concern within the Lake George Watershed as many duck populations do feed on them. The presence of the Banded Mystery Snail has been associated with decreased nearshore spawning fish populations, including bass as the Banded Mystery Snail will feed on fish embryos.

The Banded Mystery Snail is an indicator of pollution from excessive fertilizers as they are found in nutrient rich environments and will feed on chlorophyta (green algae), diatoms, decomposing mater and live plants. They are most common in areas of lakes that are experiencing littoral eutrophication and fully eutrophic lakes. They prefer sandy bottom areas, however if a littoral benthic algal bloom is present, they can be found in high numbers on rocks.

They are spread by active release from aquarium tanks, and by boats and equipment where they have attached to plant material. Eradication is nearly impossible. With further scientific data indicating the impact of this non-native species to the aquatic ecosystem, it is time for the full ecological impacts to be studied and everyone to remember to practice invasive species spread prevention.

Photo: Banded Mystery Snails.


Corrina Parnapy

Corrina Parnapy, an Adirondack native  transplanted to Vermont with her husband and son, is the District Manager for the largest Natural Resources Conservation District in the State of Vermont.  She is the lead Aquatic Biologist/ Phycologist for Avacal Biological, and writes about the natural world for the Adirondack Almanack and other Northeast publications.




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