The species is native to northern Europe and northern North America (Vancouver Island). It was present in Canada in the late 1800s but did not begin to cause problems until the early 1990s.
By 2004, didymo was present in the rivers of the western U.S. and was first discovered east of the Mississippi River in 2005 in Tennessee. In addition, didymo has undergone a recent large expansion in range and is now found in many tailwater rivers in the south and, more recently, in Quebec and New Brunswick as well as other locations around the world.
Until 2006 it was unheard of in the northeastern U.S. It was discovered during the summers of 2006 and 2007 in the Batten Kill (NY/VT), in 2007 in the Connecticut River (NH/VT), the White River (VT), and the Delaware River system (NY/PA), and in 2008 in the Gunpowder River (MD) and the Mad River (VT) (VT December, 2008).
The exact pathway of introduction is unknown, but it does spread easily through contaminated boats and fishing gear. The microscopic organisms have the ability to live out of water for a period of one to two weeks, allowing them the time to travel via boaters and fishers from water source to water source.
At first sight, one would not think the species to be a problem other than its unpleasant characteristics. While an individual cell of a didymo species cannot be seen with a naked eye, particularly during the early stages of an infestation or following heavy flows, they often form together to produce a fibrous stalk that can develop into visible mats, which is considered to look like rock snot. These mats or algal blooms block the sunlight, preventing photosynthesis, thus disrupting ecological processes and causing a decline in native plant and animal life.
Currently, there are no known methods of eradicating didymo once it is established. However, it remains a priority of the Vermont Agency of Natural Resources to limit the alga's spread throughout the region, as a precaution. Vermont ANR is cooperating with a number of federal, state and other entities to monitor and reduce the spread of didymo in the northeastern region.
Several programs have been created in Vermont to educate boaters and fishers on the precautionary measures to reduce and disinfect their gear. In Vermont, the Lake Champlain Basin Program and the New England Interstate Water Pollution Control Commission have recently received an Aquatic Invasive Species Spread Prevention Grant.
The project title for this grant is "United Against AIS in the Winooski Basin." Aquatic Invasive Species (AIS) are a major threat in the Winooski Basin. The primary goal of this project is to create a united, concerted and coordinated effort to educate communities about the threat of invasive aquatic species and how to prevent the spread into and throughout the Winooski watershed.
The project is set to start in early June 2009 and will include several workshops. The first workshop will be held in Plainfield on June 4 hosted by Friends of the Winooski River. This workshop will serve any interested community members in the upper region of the Winooski Watershed Basin.
In addition, two more workshops will be held during June and July 2009 hosted by Friends of the Winooski River and will serve the public in the middle and lower regions of the Winooski Watershed. For more information please visit the Friends of the Winooski website at www.winooskiriver.org or the Friends of the Mad River website at www.Friendsofthemadriver.org.
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