In honor of it being National Invasive Species Awareness Week, our Watershed Word of the Week is Invasive Species. An invasive species is any plant or animal species that was introduced to an area that it is not native to. These species tend to disrupt and adversely affect the habitats and bioregions they invade economically, environmentally, and/or ecologically.
In our area, one of the most common and recognized invaders is Eurasian Water-Milfoil. Milfoil is thought to have been introduced in the 1940’s and is now present in every state in the United States.
Invasive species are extremely good at taking over an area for several reasons. 1. They reproduce quickly. 2. They have no natural predators. 3. They grow rapidly and displace native species. With just these three advantages, it is no wonder when an invasive species is introduced, they take over and are extremely difficult to remove.
Invasive Species in Maine (Maine Invasive Species Network, University of Maine):
Insects
| Common Name | Species Name | Source |
| European Fire Ant | Myrmica rubra | Univ of Maine / Maine NAP |
| Gypsy Moth | Lymantria dispar | GMRI – Vital Signs |
| Spotted Wing Drosophilia | Drosophilia suzukii | Univ of Maine |
| Forest Pests including Emerald Ash Borer, Asian Longhorn Beetle, Hemlock Wooly Adelgid, Elongate Hemlock Scale, Brown Spruce Longhorn Beetle, Winter Moth, European Wood Wasp | Agrilus planipennis, Anoplophora glabripennis, Adelges tsugae, Fiorinia externa, Tetropium fuscum, Operophtera brumata and Sirex noctilio | Maine Forest Service |
The Maine Forest Service wants to know about any of the species of forest pests listed above. Contact them at (207) 287-2431 or 1-800-367-0223 (in State).
Not sure what you have? Visit UMaine Cooperative Extension – Homeowner IPM Pest ID Page or the Insect and Plant Disease Diagnostic Lab.
Marine Invaders
| Common Name | Species Name | Source |
| Asian Shore Crab | Hemigrapsus sanguineus | Maine Dept of Marine Res |
| Dead Man’s Fingers | Codium fragile | GMRI – Vital Signs |
| Lacy Crust Bryozoan | Membranipora membranacea | GMRI – Vital Signs |
| Green Crab | Carcinus maenas | GMRI – Vital Signs |
| Hairy-clawed shore crab | Hemigrapsus penicillatus | GMRI – Vital Signs |
| Chinese Mitten Crab | Eriocheir sinensis | GMRI – Vital Signs |
| Common Periwinkle | Littorina littorea | GMRI – Vital Signs |
| Rapa whelk | Rapana venosa | GMRI – Vital Signs |
If you see Asian Shore Crab, contact Peter Thayer (Maine Dept of Marine Resources) via email at pete.thayer@maine.govwith the date, location, and number of crabs you have seen
Fish Introductions
| Common Name | Species Name | Source |
| Northern Pike | Esox lucius | Maine Dept of Inland Fisheries |
The illegal introduction of any fish into any Maine water is a Class E crime, punishable by fines. If you know of an illegal introduction, protect Maine’s fisheries and call Operation Game Thief at 1-800-253-7887 or visit the MDIFW website for more information. A list of “unrestricted” fish and wildlife species are listed by the Dept of Inland Fisheries and Wildlife for possession and sale.
- If you know of a good resource not currently included here please contact Caleb Slemmons (caleb.slemmons@maine.edu) to add a link.
Terrestrial and Aquatic Plants Identification Page.
Invasive Species of New Hampshire
If you think you have identified an invasive species please call the proper authorities to manage and deal with the issue.