DEEP: Aquatic Invasive Species

Aquatic Invasive Species

An increasing number of damaging aquatic species are invading the waters of Connecticut. Zebra mussels and Eurasian water milfoil are most familiar to anglers but other exotic species may cause problems as well. You can help prevent the spread of problem species by following these simple suggestions!

{Milfoil.}    {Fanwort.}    {Water chestnut}
{Invasive weeds on a trailer.}    {Zebra mussels.}

Effective January 1, 2020: An Aquatic Invasive Species (AIS) Stamp fee will be collected from any person who registers a vessel or renews a vessel registration in Connecticut.  Boaters with out of state registrations who boat on Connecticut inland waters will also be required to pay an AIS fee. 
For more information, please see AIS FAQ page. 

Before Leaving a Boat Launch, practice the Clean, Drain, Dry technique.
Clean:  {Woman cleaning her boat.}
  • Inspect and remove all visible plant, fish, and animals as well as mud or other debris at the launch. Do not transport them home.
  • Check trailer, including axle and wheel areas - in and around the boat itself: anchor, props and jet engines, ropes, boat bumpers, paddles (anything that came in contact with the water).


  • Eliminate all water from every conceivable space and item before you leave the area you {Person draining his boat.} are visiting. 
    • Remove the drain plug from boats and put boat on an incline so that the water drains out
    • Drain all water in live-wells, bilge, ballast tanks, transom wells, kayaks, canoes, rafts, motors, jet drives, boat hulls, scuba tanks and regulators, boots, waders, bait buckets, seaplane floats and swimming floats.


  • {An example of cleaning boat equipment.} Dry Equipment, if possible, allow for 5 days of drying time before entering new waters.
{Graphic showing parts of boat to inspect}
The "Clean, Drain, Dry" technique is the suggested Best Management Practice and will prevent the further spread of aquatic invasive species.

Additionally, under the law
  • Boaters must inspect their vessel for vegetation and aquatic nuisance species and properly remove and dispose of all vegetation and nuisance species before transporting the vessel. You can be fined $95 per violation (CGA 15-180) and Public Act 12-167. {Invasive plants on a trailer.}
  • The importation, transportation, sale, purchase, cultivation or distribution of a number of invasive plants including the following aquatic plants is prohibited.*  Violators can be fined $50 per plant! (CGS 22a-381d)

    The importation, transportation, sale, purchase, cultivation or distribution of a number of invasive plants including the following aquatic plants is prohibited*:

     curly leaved pondweed
    (Potamogeton crispus)
    Eurasian water milfoil
    (Myriophyllum spicatum) 
    water chestnut
    (Trapa natans) 
    (Hydrilla verticillata) 
    (Cabomba caroliniana) 
    variable water milfoil
    (Myriophyllum heterophyllum) 
    (Egeria densa) 
    common reed
    (Phragmites australis) 
    purple loosetrife
    (Lythrum salicaria) 
    (Myriophyllum aquaticum) 
    American water lotus
    (Nelumbo lutea) 
    giant salvinia
    (Salvinia molesta) 
    onerow yellowcress
    (Rorippa microphylla) 
    Pond water-starwort
    (Callitriche stagnalis) 
    brittle water-nymph
    (Najas minor)
    yellow floating heart
    (Nymphoides peltata) 
     yellow iris
    (Iris pseudacorus) 
    (Rorippa nasturium-aquaticum)**
    * Except for eradication, education or research purposes.
    ** Except for watercress without reproductive structures sold for human consumption.
Violators can be fined $50 per plant! (CGA 22a-381d)
Additional Information