Photo: Conn. DEP

Didymosphenia geminata, an invasive alga known as “didymo,” or rock snot, was found in the West Branch of the Farmington River in Connecticut on March 18. Several anglers reported the didymo sighting to the Connecticut Department of Environmental Protection. A lab in Vermont confirmed that the alga is didymo, and the department announced the finding on March 29.


Didymo was found in several states in the northeastern U.S. in the summer of 2007, including New York, New Hampshire, and Vermont. This is the first time it has been found in Connecticut.


Didymo is considered an invasive species because it can grow in dense mats that carpet the stream bottom. It’s not clear where didymo originated. It’s been known in streams in northern Europe and northern North America for some time. It was first found in the Southern Hemisphere, in New Zealand, in 2004. Researchers suspect it is being transported from place to place through recreational activities like fishing (on waders), and kayaking.


For more on the Connecticut situation, including prevention strategies and background on the algae, read the article in The Hartford Courant, or the Connecticut DEP press release.