Prevention and Management

AIS Prevention and Management

 

Preventing aquatic invasive species from reaching Connecticut lakes and ponds is the preferred method of control. People can move invasive species from one body of water to another on boats and trailers. Connecticut legislation (Connecticut Public Act No. 03-136) imposes fines on individuals found transporting invasive non-native plants in this way. Posting signs at boat launch ramps detailing what invasive species look like and the importance of checking and cleaning boats and trailers can be helpful. Plants liberated from aquariums or water gardens are another way non-native aquatic plants are introduced into freshwater ecosystems. Properly disposing of aquarium plants and isolating water gardens will help reduce these risks. Public Act No. 04-203 restricts the sale of most invasive aquatic plants in Connecticut.

Unfortunately, the spread of invasive non-native aquatic plants in Connecticut is likely to continue because large numbers of lakes and ponds already contain the plants and natural movement by flowing water and aquatic wildlife is largely uncontrollable. Eradication of new infestations is more likely to be successful than elimination of large areas of established plants. Volunteer monitoring programs can be initiated to routinely check water bodies for new plants. The CAES Office of Aquatic Invasive Species (CAES OAIS) can offer assistance to volunteers on how to survey and identify aquatic vegetation through their invasive aquatic plant workshops.

Prevention: Clean, Drain, Dry

Check your boating and fishing equipment for invasive species. Carefully examine common attachment points such as trailer bunks, axles, rollers, lights, transducer, license plate, and motor props for any plants, mud, or debris. Run your hand along the hull of your boat to check for changes in texture. If it feels like sandpaper, it could have zebra mussels or other invasive species attached. Also inspect all gear used during your trip, including fishing gear and anchor lines.

Clean any visible mud, plants, fish or animals before transporting equipment. Discard materials in a trash can. Do not wash or release material into a waterbody. Some invasive species, such as zebra mussels, can be difficult to remove from a boat hull. They first need to be killed by water or steam that is 140°F, then they need to be removed by a brush or pressure washer. Dump unused bait in trash cans and bucket water on dry land above the high water line, not in the water.

Drain all water holding compartments including ballast tanks, live wells, and bilge areas. Drain your boat before you leave an access site. Waterskis or wakeboards sometimes have ballast tanks; be sure to drain them. Drain your live well if you have one.

Dry boats, trailers and all equipment before use in another waterbody. The most effective way to ensure that no invasive species or fish diseases are transported to a new body of water is to completely dry your boating and fishing equipment. Drying times vary significantly depending on the type of equipment, air temperature, and relative humidity. While the outside of a boat will dry relatively quickly, bilge, live wells, and other parts of a boat not reached by the sun or without good air circulation will take additional time to dry completely. A minimum of 5-7 days drying time in dry, warm conditions is recommended.

Disinfect anything that came into contact with water if it cannot be dried before reuse. Smaller items can be disinfected with hot water to kill aquatic invasive species and fish diseases. Soak all equipment in water that is at least 140°F for 30 seconds.

Management Techniques

Many techniques are available for controlling unwanted aquatic vegetation. Regardless of the method, knowing the potential harmful effects on non-target organisms is important.

Mechanical Control

Mechanical control includes hand-pulling, machine harvesting, hydroraking, benthic barriers and dredging. Typically, these methods are used in localized areas. Dredging requires permits from local, state and federal agencies.

Water Drawdown

Water drawdown, particularly during the winter, when freezing temperatures can damage plants, is a low-cost weed-control option. The Connecticut Department of Energy and Environmental Protection (DEEP) must be notified before any drawdown.

Herbicides

Chemical aquatic weed control involves applying a herbicide to decrease the population of a plant. Invasive plants are rarely eliminated, but the recreational value of a lake or pond can be improved, and the spread of the invasive plant can be slowed. Selecting the proper herbicide and the time of application requires accurate information on the life cycle of the invasive plant. A permit from the state DEEP is required before an aquatic herbicide can be used. Experts at CAES IAPP and the DEEP can answer questions on the use of aquatic herbicides.

Biological Control

Biological control agents, including beneficial insects and microbes, may someday be viable aquatic weed control alternatives. To date, the only biological control used successfully in Connecticut is a plant-eating fish, the grass carp (Ctenopharyngodon idella). This fish is not native and must be certified as sterile (triploid) to assure it will not reproduce in the environment. The DEEP monitors the release of this fish, and a permit is required before they can be purchased. Typically, grass carp are used in small ponds. Containment of grass carp to the body of water where they are introduced is required, and special screens are needed at inflows and outflows.  CAES IAPP started a project in 2006 to assess the distribution and abundance of biological control agents for Myriophyllum spicatum.  (Follow this link for more information on the biological control study.)

Nutrient Reduction

Because plants need nutrients to proliferate, reducing the nutrients reaching the water body may inhibit the growth of invasive aquatic plants. Maintaining unfertilized shoreline buffer zones and minimizing the misapplication of fertilizer to paved areas can reduce the amount of fertilizer that reaches lakes and ponds. CAES offers soil tests that determine fertilizer amounts based on plant needs.