Maine natural resource agencies participating in the largest invasive species awareness effort in the U.S.

February 21, 2020

For more information contact: Jim Britt at

The collaborative initiative aims to bring attention to the impacts, prevention, and management of invasive species.

AUGUSTA - Maine's natural resources agencies are inviting everyone who cares for our environment to get involved in National Invasive Species Awareness Week (NISAW), February 24-28, 2020. NISAW is a nationwide event designed to raise awareness of invasive species. In Maine, invasive species are already impacting our lakes, rivers, wetlands, forests, and ocean, and they are taking a toll on our natural resources economy.

"Our State Parks and Public Lands, our farms, forests, and water bodies are all being damaged by invasive species," commented Department of Agriculture, Conservation and Forestry (DACF) Commissioner Amanda Beal. "Everyone acknowledges that we can and should do more to help, and National Invasive Species Awareness Week is a perfect time to learn how to prevent and manage invasive species."

Invasive pests, including emerald ash borer, browntail moth, multiflora rose, Asiatic bittersweet, milfoil, green crabs, and countless others, are harming Maine's unique natural resources, recreation and tourism economy, and the livelihood, traditions, and health of thousands of Maine people.

Mainers are fortunate: most of our lakes and rivers are free from invasive aquatic plants but we need to be vigilant to stop new infestations," said Department of Environmental Protection (DEP) Commissioner Jerry Reid. We urge users of Maines waters to clean debris from all boats and equipment, drain water from engines, boat bilges and live wells after use and dry anything that contacts water before moving to another lake or river.

Recognizing that combating invasive species is in the best interest of all who live in and visit Maine, the states four natural resource agencies are encouraging everyone to participate in NISAW Part I, Monday, February 24 to Friday, February 24, 2020. NISAW Part II occurs May 16-23, 2020.

Unauthorized introductions of fish and aquatic plants into Maines waters can create irreversible impacts and can alter ecosystems, forever, said Department of Inland Fisheries and Wildlife (DIFW) Commissioner Judy Camuso. Maine is home to some wonderfully special (and fun to catch) native fishery resources and protecting what we have is a responsibility of everyone that enjoys Maines unique natural resources.

Invasive species are those plants and animals, including insects and microbes, that are not native to Maine, and that cause harm to the environment, the economy, and human health. Maine, because of its unique natural resources and its status as the most forested state in the nation, is under threat from numerous invasive species.

The health of Maines marine environment is critically important, and preventing the introduction of invasive species is a significant focus of ours, said Department of Marine Resources (DMR) Commissioner Patrick Keliher. Awareness around this issue is important and underscores the value of our work to safeguard commercially and ecologically valuable species through our inspection and permitting process for imported species, and our work to understand and support efforts to control invasive species like green crabs.

Invasive Threats

Of Maines nearly 6,000 lakes, fewer than one percent, fortunately, are known to be currently infested with invasive aquatic plants. These plants can hijack the habitat of native fisheries, flora, and fauna; degrade water quality; diminish property values, and reduce water recreation opportunities, including fishing, boating, and swimming. Eleven invasive aquatic plants are identified in Maine law as illegal to import, sell, and transport, with six already discovered in some of Maines lakes. DEP and DIFW spend more than $1 million annually fighting these invasive plants.

Invasive terrestrial plants threaten Maines wild places and can harm working forests and productive farms. Plants such as glossy buckthorn steadily invade high-quality forests, crowd out native trees, shrubs, and wildflowers, and out-compete the next generation of trees. Along rivers and streams, Japanese knotweed forms dense stands that prevent colonization by native plants. Knotweed roots and shoots are carried downstream in floodwaters, spreading the problem to new locations. Maine prohibits the sale of thirty-three species of invasive plants, and over 100 species are listed on an Advisory List of invasive plants to help guide land managers. The Maine Natural Areas Program (MNAP) within DACF tracks invasive plant distribution and management using the online mapping tool iMapInvasives and encourages Mainers to work with their town conservation commission, local land trust, or garden club to spread the word about invasive plants and work together to remove them. For more information, visit the MNAP website or

Maines forest trees are under attack from multiple invasive forest insect pests, and the threat of new pests invading Maine is constant. Invasive insects such as emerald ash borer and hemlock woolly adelgid will forever change Maines forests as they spread and continue to kill trees throughout the state, while other invasive pests like browntail moth affect quality of life and human health. Other invasive insects like Asian longhorned beetle or diseases like oak wilt have similar potential to damage Maines forests if they arrive here. The Maine Forest Service has a strict out-of-state firewood ban to prevent devastating introductions like these and natural resource managers everywhere continue to encourage the use of local or heat treated firewood only. At DACF, the divisions of Forest Health & Monitoring and Animal and Plant Health, working together as Maine Bug Watch, continue to monitor and control invasive insects and diseases whenever possible.

The illegal stocking of species like northern pike, black crappie, or largemouth bass can have the most significant and obvious impacts to Maines native fisheries, but sometimes the release of new fish species can occur for other reasons. Often these illegal acts are intentional, like when someone wants a certain species of sport fish in a lake close to their home. Unintentional introductions can happen as a result of negligence related to threats found in an anglers bait bucket. While the level of threat from this type of introduction may be less than that from the intentional establishment of large predatory species, impacts to native fish populations can occur. DIFW already limits the fish species that can legally be used as bait and prohibits the unauthorized importation of baitfish from outside the state as two strategies to reduce risk, but recently a third strategy was employed to increase awareness related to using live fish as bait. In January of 2020, DIFW changed fishing regulations in northern Maine to prohibit the use of live fish as bait under the general law and only allow fishing with live bait fish on certain waters (which are specifically listed in Maines Open Water and Ice Fishing Laws). This change reinforces the importance of this regions abundant native and wild fishery resources and stresses the potential damage to those fisheries when baitfish are introduced where they dont belong.

Top Five Actions Everyone Can Take Right Now to Prevent and Manage Invasive Species

Look for woodpecker blonding on ash trees. This shallow flecking of the bark by woodpeckers is a common sign of an emerald ash borer (EAB) infested ash tree. When you think you see blonding, take the best quality photo (phone pictures are okay), note your location, and report the findings on our EAB Report Form.

Learn how to identify invasive plants that might be growing on your property. For help recognizing problem plants, consider ordering a copy of the Maine Natural Areas Programs Maine Invasive Plant Field Guide. The guide has detailed photos and recommended control methods to help to reclaim the landscape. Another great way to increase invasive plant awareness is to volunteer with a local land trust or a conservation commission, to help remove invasive plants on local public lands.

Be on the lookout for the invasive tree of heaven, which is host to a new invasive insect threat, the spotted lanternfly. If you think you have seen tree of heaven in Maine, please report it to

Clip those winter webs. For those of us in browntail moth territory, right now is a great time to clip out webs of overwintering browntail moth caterpillars before they become active. Learn more.

Don't release aquarium fish and plants, live bait, or other exotic animals into the wild. Research before buying an exotic pet and commit to its care; learn more at And remember, it is illegal to import any freshwater fish into the state of Maine without a permit from the Maine Department of Inland Fisheries and Wildlife.

For more information on all the Maine NISAW events, go to

For more information about nationwide NISAW activities visit

For more information about Maine natural resource agency invasive species programs visit


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