Just say ‘no tanks’ to invasive plants

14 years ago

    “Your favorite lake … it’s infested with an invasive aquatic plant.”
    These words haunt anyone who cares about Maine lakes. For too many Mainers and seasonal visitors, they describe a grim and permanent reality than can begin with a single misguided release of aquarium pets and plants.
    Damariscotta Lake has Maine’s latest infestation with the discovery of hydrilla in a .3 acre lagoon in August 2009. This is no minor matter for this 14-mile long lake that defines much of the natural character of the towns of Jefferson, Newcastle and Nobleboro. That small infestation has the potential to spread throughout the entire lake.
    Ask an aquatic biologist about hydrilla and you’ll hear about how quickly and thoroughly this alien plant damages lakes and ponds. It spreads within a pond by fragments, seeds, tubers, winter buds and surface runners. In time this pest can create a crowded habitat unfriendly to fish and birds. Hydrilla also fouls boat props, drinking water intakes, and boating areas.
    Originating in Africa and Southeast Asia, hydrilla arrived in Florida in the 1950’s as a commercial aquarium plant prized for its hardiness and prolific growth. By 1960, the first hydrilla was discovered in that state’s waters. Floridians now spend more than $20 million annually in herbicides and mechanical harvesting just to keep waters navigable.
    There’s no direct evidence how hydrilla ended up in Damariscotta Lake. It may have hitchhiked on a boat, but the dumping of a fish tank containing hydrilla is also a leading suspect.
    How can that be?
    Surf the Internet and you quickly discover that pet, water garden, and even classroom science supply companies sell several invasive plant species found on Maine’s list of 11 most unwanted plants. These plants have been banned from sale in Maine since 2001 (http://www.maine.gov/ dep/blwq/topic/invasives/invaquarium.htm). These plants have varying common names, so consumers may not recognize whether plants offered for sale are the invasive kind.
    Even responsible vendors may unintentionally sell these plants. Invasive species such as hydrilla can contaminate batches of desired plants and, unknown to both buyer and seller, be passed along in transactions.
    Given the ease of buying nuisance species, careful consumers and responsible vendors are necessary to limit their spread to Maine waters. The potential for a plant invasion can be avoided if consumers do the following:
• Be responsible and avoid buying troublesome plant species. Research what you buy.
• Over-the-counter transactions are best as you can inspect your purchase personally prior to payment. Also, Maine merchants are expected to be aware of state laws that prohibit sale of invasive species.
• Never dump tank contents — especially plants or live animals that could spread diseases — into natural waters. Find another home for unwanted pets and plants and put remaining plants into the trash.
    This column was submitted by Paul Gregory, an environmental specialist with the Maine DEP’s Bureau of Land and Water Quality. In Our Back Yard is a column of the Maine Department of Environmental Protection. E-mail your environmental questions to infodep@maine.gov or send them to In Our Back Yard, Maine DEP, 17 State House Station, Augusta, ME 04333.