First, toilet paper algae, now crabs with furry claws. Talk about your exotic species.

Yesterday, we told you about toilet paper algae, also known as rock snot, coating riverbeds in Vermont and New Hampshire. It’s an invasive species originally found in northern Europe and China.

Today, news reports on the East Coast are warning about signs that the Chinese mitten crab may have established a breeding population in the Chesapeake and Delaware bays. Officials in Maine and other states issued warning to anglers to keep an eye out for the crabs, and are requesting that they capture and report any that they may find.

The crab has slowly made its way from Asia to Europe to the United States, possibly hitching rides in the ballast tanks of big ships.

The crab is named for its furry pincer claws. It actually spends much of its life in fresh water rivers, returning to coastal estuaries to spawn. It’s regarded as an aggressive invasive because it can take over habitat from native animals, foul commercial fishing nets and water intakes, and accelerate erosion by burrowing into shorelines and embankments.

Look here for the Baltimore Sun story about the crabs making themselves at home in the Chesapeake. And here is Maine’s warning and fact sheet on the crab.

A new invasive species has arrived in New England and could appear soon in a river near you.

But, based on the descriptions coming out of Vermont and New Hampshire, let’s hope not.

Agencies in those states are warning anglers about an invasive freshwater algae known as didymo or, more descriptively, rock snot. It’s been found in the northern reaches of the Connecticut River and in the White River, the first official reports of Didymosphenia geminata in the northeastern United States.

Didymo is a microscopic algae that blooms into thick, white or light brown mats that can cover several miles of river bottom. It’s also been called toilet paper algae because it can resemble strands of soaked toilet paper.

It is considered a threat to wild trout and other river inhabitants and there’s no known way to remove it once it shows up. State officials in Vermont are warning anglers that the algae can be spread on their clothes, waders and fishing gear from one stream to another.

It has not been detected in any Maine rivers, according to the Department of Environmental Protection.

The descriptions from Vermont sound a lot like a sticky, toilet paper-like substance that covered the bottom of Lords Brook in Lyman on and off during the past year and a half. That growth, however, was identified as a fungus that’s native to the stream, according to the DEP. Officials believe the Lords Brook fungus bloomed because of nutrient-rich stormwater runoff from a nearby composting operation.

Look here and here for news stories about the Vermont invasion.