Aquatic Invasive Species
Vermont Freshwater Fishing
By Shawn Good, Fisheries Biologist, Vermont Fish & Wildlife
The introduction and spread of aquatic invasive species (AIS) is one of the biggest threats that Vermont’s lakes, ponds, rivers and streams face today. Invasive species impact the health of Vermont’s waterbodies and aquatic communities by changing water quality, altering ecosystem functions, threatening fish habitat, and by preying upon or out-competing native species for food and habitat.
Over 50 nonnative aquatic species are already established in Vermont waters, including plants like Eurasian watermilfoil and water chestnut, invertebrates like zebra mussels and spiny water flea, and fish such as alewife, rudd, and tench. Aquatic invasive species can also include fish diseases and parasites, such as whirling disease and Heterosporis, which affect the muscle tissue of fish such as perch and walleye. Invasive species can reduce the quality of Vermont’s recreational angling opportunities that we all enjoy and cherish.
Vermont Fish & Wildlife and the Department of Environmental Conservation work diligently to address AIS threats by setting laws and policies on invasive species transport and introduction, and implementing outreach and educational programs such as the Public Access Boat Greeter Program, designed to inform water recreationists about invasive species spread prevention measures. Fisheries biologists, natural resource managers and water users alike are concerned about the potential for new AIS introductions such as Asian carp, round goby, hydrilla or viral hemorrhagic septicemia virus being introduced to Vermont waters. Once invasive species become established, it’s virtually impossible to eradicate them.
Preventing new AIS from being introduced and established AIS from spreading to new waters is critical to protecting the health of Vermont’s aquatic ecosystems. Any equipment used on or in the water can collect and spread AIS. Boats, kayaks, trailers, fishing equipment, scuba gear and other items can spread AIS from one body of water to another unless properly cleaned, dried or disinfected after use. While many AIS are easy to see, such as Eurasian watermilfoil strands stuck on a boat trailer, others are too small to be noticed, such as spiny water flea, larval zebra mussels, or viruses and bacteria that cause fish diseases.
Vermont has a law prohibiting the transport of all aquatic plants, and zebra and quagga mussels, and it is everyone’s responsibility to follow this law by cleaning, draining and drying boats, trailers, waders and other aquatic gear to prevent the transport of AIS.
When boating, fishing or recreating on Vermont waterways, you can help protect the health of aquatic ecosystems by taking these simple precautions:
CLEAN and remove all visible aquatic plants, zebra mussels, mud and other debris from boats and other watercraft, trailers, anchors, and all water-related equipment before leaving any waterbody or shore.
DRAIN bilges, live wells, wet wells, bait containers and boat motors before leaving the waterbody. Motors can be drained by lowering them all the way down and briefly starting the engine (1–2 seconds), which will purge water from the system. Always keep drain plugs out and water-draining devices open while transporting watercraft.
DRY your boat and gear. Aquatic invasive species need moisture to survive. Keep quick-dry towels with you and wipe down your equipment to remove any residual water. Make sure you wash and dry these towels before using them again on another waterbody.
DISPOSE of unwanted live bait, including minnows, leeches and worms, in the trash.
Thoroughly cleaning all gear can be started at the boat ramp, but further cleaning and disinfection is recommended later at home. Spraying your gear with high-pressure water or rinsing it with hot water (120°F for at least 2 minutes or 140°F for at least 10 seconds) will kill most aquatic invasive species. Allowing gear to dry for at least 5 days before using on another waterbody is also effective.
To learn more about aquatic invasive species in Vermont, and what you can do to help prevent
their introduction and spread, please visit
We all must do our part to prevent the introduction and spread of aquatic invasive species in Vermont to ensure that our waterbodies stay healthy for the enjoyment of future generations.
Step By Step
Felt-sole wader ban repealed
On July 1, 2016, Vermont repealed the law prohibiting the use of felt-sole waders and boots; they are once again legal to use.
The ban began in 2011 in response to nuisance blooms of the algaealso known as Didymo or rock snot. At the time, Didymo was thought to be an invasive species in Vermont waters. It was believed that the porous material on the soles of waders would trap the microscopic algal spores and spread them to new waters when the waders were used elsewhere.
Recent scientific studies have documented that Didymo is actually native in Vermont and across much of the northern region of North America. Didymo spores are present in most Vermont rivers, but only become nuisance algae blooms under certain favorable environmental conditions. Research continues to better understand what makes these blooms occur.
The repeal of the felt-sole wader ban does not mean that aquatic invasive species spread prevention is no longer a priority in Vermont. Instead, this demonstrates how the State
of Vermont makes all efforts to stay current with the science and work to fairly balance natural resource conservation with public use of these resources.
In order to maintain Vermont’s healthy
lakes, ponds, rivers and streams, we must
all do our part to prevent the spread of aquatic invasive species.
What a Nuisance!
Some of the Aquatic Invasive Species in Vermont Waters
North American Native Fishes Association
Invasive baitfish species first found in Lake St. Catherine in 1997 and Lake Champlain in 2004. May displace smelt and other native forage fish through competition for food and space resources. Trout and salmon that feed extensively on alewives may also suffer reproductive failure. Alewives may not be used as bait in Vermont except for on Lake Champlain, and only as dead bait.
GB Nonnative Species Secretariat
Invasive clam species found
in Lake Bomoseen in 2016
can multiply quickly, clogging
water intake pipes and other
water systems, deplete resources
needed by native species and increase algae blooms. Easily spread through small amounts
of sediment or water, Asian clams can be inadvertently transported
by boat hulls, bilges, live wells
and additional boating equipment, as well as by bait buckets and
other fishing equipment.
Alison Fox, University of Florida, Bugwood.org
Prolific invasive aquatic plant found in Lake Champlain and many inland lakes in Vermont. May interfere
with boating and swimming, and
can displace native aquatic plant species. Easily spread when plant fragments are caught and moved
on boat trailers, propellers,
anchors and other equipment.
Jeff Gunderson, Minnesota Sea Grant
Tiny invasive crustacean that first appeared in Lake Champlain in 2014. Alters native plankton populations, clogs fishing rod guides and fouls fishing line. Spread by hitchhiking on boating or fishing gear that isn’t cleaned or in bilge water, bait buckets or live wells that aren’t drained before moving to a different waterbody.
Prolific invasive aquatic plant found in southern Lake Champlain and a few inland lakes. Interferes with boating, hunting and fishing, and displaces native aquatic plant species. Spreads by seeds or parts of plants caught on boats and equipment.
Dennis Roberge, Courtesy of Maine VLMP
Invasive aquatic plant recently discovered in Halls Lake, Newbury, Vermont, as well as South Bay and Missisquoi Bay, Lake Champlain. Easily spread by fragments with impacts similar to the closely related Eurasian watermilfoil, but may be even more aggressive and difficult to control.
U.S. Fish & Wildlife Service
Tiny D-shaped invasive mollusks, well established in Lake Champlain and Lake Bomoseen. Clogs water intake pipes, damages boat engines, obscures historic shipwrecks and may alter native plankton populations. Adult zebra mussels can attach to and be moved on boat hulls, engines and other equipment. Microscopic larva can get trapped and moved in water of boat engines, bilges, bait buckets and live wells.