An invasive slug species has slimed into Anchorage

An unusually wet, cool summer has made Southcentral Alaska a particularly hospitable place for an invasive slug species that appears to have made a home in Anchorage’s Hillside.

Scientists are asking Anchorage residents to keep an eye out for sightings of the European black slug, a gastropod that is significantly larger than Alaska’s native slug species, so they can track the possible impacts on agriculture and the environment, said Joey Slowik, integrated pest management technician with the Matanuska Experiment Farm and Extension Center.

The slugs have the potential to be a major nuisance for gardeners and growers because of how much they eat, Slowik said. He described them as “a fairly robust slug” that are about 4 inches long and come in several colors, including brown, gray, green and orange. They have a smooth mantle — the area behind a slug’s head — and their backs are covered in featherlike ripples.

Nearly 50 of the invasive slugs were spotted at the Rabbit Lake Trailhead on Anchorage’s Hillside during the first week of July, as well as another nearby trailhead, Slowik said. The sightings could be a sign that the species has become established in Anchorage for the first time, he said.

The European black slug was first introduced into Alaska in the 1980s in Cordova, Slowik said. It eventually made its way to Juneau and Ketchikan, likely hitching a ride on fishing gear, and is now prevalent across Southeast. A few years ago, people started seeing the slug in Whittier and Girdwood. But it mostly seemed to have skipped Anchorage until now, he said.

Slowik said the cool, damp weather this summer in Southcentral Alaska may have played a role in the gastropods’ latest move. The cannibalistic slugs are drawn to hiking trails because of how much dog poop is often found there, Slowik said — “they like to eat poop and each other,” he said.

“It’s definitely a good slug summer,” he said. “June is usually dry, and maybe keeping the slugs away, but this year, definitely, they’re hopping over.”

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Slowik said the possible impact the slugs may have on the environment isn’t yet known. That’s why it’s helpful for people to report sightings as a way of better understanding the gastropods, their habitat, and their impact.

“In the Southeast, they’re definitely a major pest species. We’ve worked a lot with the small growers down there, and they’re definitely a major pest to agriculture,” Slowik said.

He encouraged Anchorage residents to report slug sightings at alaskapestreporter.org, which includes the option to upload photos and note the location and date of the sighting.

Since the slugs are an invasive species, Slowik said Alaskans could kill the slugs if they see them, but it might not make much of a difference because of how quickly they reproduce.

“I don’t know if we can really stop them, but we can find some methods to help control them,” he said.

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