European black slug (Arion ater)

image of European black slug adult

The European black slug (Arion ater) has been found on some islands in Maine. We are currently trying to determine its distribution in the state. If you see a large black slug, especially along the coast, please take some photos, note the location, and report it to

The European black slug, Arion ater, is a large slug from Europe that was been confirmed in Maine in 2018 on the island of Vinalhaven. It is considered a pest of agriculture and can cause damage to a number of ornamental, vegetable, and fodder crops. A. ater is often found in disturbed sites, like gardens and campgrounds, and will consume living and dead plant material, fungi, feces and carrion.

Currently, we are aware that Arion ater exists on Vinalhaven and Greens Island in Maine. We are interested in knowing other locations in Maine where Arion ater may be present. If you notice a large black slug, please take photos and submit them with the location to

Exotic Mollusk Survey Info Sheet 2021 (PDF)