Invasive crawfish move in

WOODSBORO, Md. (AP) — The rusty crayfish has marched across the Mason-Dixon Line into Maryland, alarming state officials who are concerned the fast-growing crustacean will displace its native cousins.

“Rusty crayfish are a huge problem, the most notorious of crayfish,” said Jay Killian, a biologist with the Maryland Department of Natural Resources as he waded in hip boots in the Monocacy River, trying to net the invaders. “They grow really fast, and they eat native crayfish and out-compete them for shelter.”

State officials, who think the species hopped a ride to Maryland in the bait buckets of fishermen, threaten fines of $125 for anglers who dump bait buckets with exotic species into local streams.

The species moved into the state from Pennsylvania and has been seen in the Monocacy River in Frederick County and Conowingo Creek in Cecil County.

“It appears to be working its way south,” Ronald Kauda, director of the Monitoring and Non-Tidal Assessment Division for the Maryland Department of Natural Resources, told the Frederick News-Post.

The sale of bait and pets over the Internet has also added to the problem, state officials said.

Rusty crayfish are a freshwater species and aren’t likely to pose a threat to the Chesapeake Bay, but Mr. Klauda said they could spread into other streams and rivers, much like the virile crayfish, which came south from the Hudson River and was also used as bait.

Rusty crayfish congregate in slow-moving sections of rivers and are not expected to cause problems for trout, which prefer fast-moving cold water, but could cause problems for bass.

Hoping to prevent the worst, state officials increased monitoring and began a “Don’t dump bait buckets” education campaign.

“It’s kind of Russian roulette with the exotic species,” Mr. Killian told the Baltimore Sun. “You never know when they are going to cause real problems.”