Invasive Species Sampling 2023
Once again, we have been fortunate to have applied and been chosen to do fully funded water sampling in Lake Vernon. The planning is done by FOCA (Federation of Cottagers Associations) with the program and testing done by the Invasive Species Centre (ISC) in Peterborough. This program is in its 3rd year. Mussels and spiny water fleas were the focus of the first 2 years. At this time, Lake Vernon does have spiny water fleas and a bay with Trap Door snails. This year, the high priority species are European Water Chestnut and Water Soldier. Previous sampling would involve 3 sites and the use of plankton haul nets plus the Environmental DNA kits. This year is single sited sampling preferably at a high flow access point/launch where these aquatic plants are most likely to first show up. Why only these 2 invaders? We are in a vulnerable region and funding. Testing occurs between August 18th and September 4th as they are better able to detect plants growing all season. How sensitive is the EDNA? The water sample would have to be within 500m of the plant to be positive. What are the aquatic invaders that we will be testing for?
Water Soldier (WS) is an invasive aquatic perennial plant native to Europe and Northwest Asia. It is sold for use as an ornamental plant in water gardens which is the most likely source of its introduction to the wild. It is spread intentionally to water gardens and unintentionally by boat/trailering. They look similar to a floating spider plant. This plant can form dense mats of floating vegetation, crowds out native vegetation and decreases biodiversity. It can impact activities such as boating, angling and swimming (sharp serrated leaf edges can cut swimmers).
European Water Chestnut is an aquatic perennial plant that grows in shallow or deep water. It was brought to North America by a gardener in Massachusetts. It is found in Ontario and Quebec. Ontario sites are Niagara, Kingston, Perth and Ottawa.These plants have green leaves with sharply toothed edges and hard seeds with barbed spines. The plant can grow to 30cm in diameter. These plants like the WS can form mats of floating vegetation, crowds out native vegetation and decreases biodiversity and the other above mentioned. Also, the plant’s hard nuts can accumulate on shore and cause injury when stepped on.
Trapdoor Snails In Lake Vernon
It has recently been brought to the LVA’s attention that there has been an explosion of the number of Trapdoor Snails, an invasive species, in certain areas of Lake Vernon. On August 1st, two LVA volunteers helped a permanent resident, who has been vigilantly trying to remove the snails in her waterfront area, hand pick the snails from the lake. Within 30 minutes in the water, three volunteers took out a 10 litre bucket of snails.
What does this mean for our lake? These snails achieve very high densities and adversely affect aquatic food webs. They compete with native snails for food and habitat and contribute to their decline. This species also clogs screens on water intake pipes, making them an economic nuisance as well as an ecological threat. Trapdoor Snails feed on algae and plankton, leading to clearer water but also encouraging monocultures of aquatic plant growth, which can make recreating in an area of the lake difficult. They also carry parasites that can affect waterfowl.
How did they end up in our lake? They could have arrived on a boat hull, trailer or propeller, a live well, an aquarium, or even a dock or toy from a lake with Trapdoor Snails. Lacking natural predators, they are prolific reproducers, producing up to 400 offspring in their lifetimes.
So, what can we do? Prevent Invasive Species from spreading. It is now provincial law that you need to drain your boat (including kayaks, canoes and sailboats) and wash it with high pressure hot water or let it dry in the sun for 5 days before taking it to another body of water. Never dump aquarium fish or plants into the lake.
If you do suspect an invasive species, please report it by phoning 1-800-563-7111 or via http://www.EDDMaps.org/Ontario.
If you do have a population of Trapdoor snails on your waterfront (see description below), it is recommended that you remove them, place them in a freezer for 4-6 hours and then bury them away from the water. Confirm that the snail you have found is, in fact, a Trapdoor Snail by sending a photo of it to the EDDMaps website.
Nets and buckets will be provided.
6.5 cm in length
Brownish to olive-green in colour
Shell has six to seven whorls
Live ones have an operculum “trap door” that allows the snail to close itself within its shell
Can survive out of water for days by closing their shells
Help protect our lake from invasive species. Remember to Clean, Drain & Dry your boat (including canoes and kayaks) between uses. Since 2022, it has been the law to do so in Ontario (Ontario Regulation 354/16).
