At the July 7th LSPA Weed Watch Meeting, speaker Amy Smagula from DES discussed a potential new threat to NH lakes, an invasive alga called Didymosphenia Geminata, or “Didymo” for short. On July 10th, the presence of Didymo was confirmed in the Connecticut River. This is the first northeast body of water to be so designated. This alga has been invading fresh water bodies in Asia, Europe and the southern and western states of the US. It is now very close by.
The concern is that this single-celled alga has been extending its range and tolerance for warmer, nutrient-rich waters. According to the Vermont Agency of Natural Resources, Didymo can form very thick mats that smother fish habitats, and harm insect and mussel populations. The EPA information indicates that it uses stalks to attach to streambed rocks, eventually shredding into the stream. The mats look slimy but feel like wet wool. Photos of “Rock Snot” show rather disgusting-looking clumps worthy of its nickname.
From the EPA’s White Paper on Didymo, “it is the only freshwater diatom to exhibit large scale invasive behavior on a global scale…with the capacity to produce inordinate amounts of stalk material”. The importance for the Lake Sunapee region is that this can impact fisheries, ecosystem function, our surface water supply, water recreation and ultimately our economy. It appears that knowledge about Didymo is limited.
Didymo is spread by recreational gear and can remain viable for several days if moist. It can also be transferred in microscopic amounts. It is not possible to eliminate didymo once it has been introduced. Foremost among the recommendations from EPA and others is for people to take action to minimize spread of Didymo. Some recommendations to minimize spread are as follows:
FIRST: The best solution is to restrict equipment for use in a single waterbody.
If this is not feasible, then “check, clean, dry”:
CHECK: Before leaving a water body’s edge, look for clumps of algae and sediment, and remove them. Leave them at the site!
CLEAN: Soak all gear for at least one minute in 2% solution (by volume) of household bleach or 5% solution (by volume) of dishwashing detergent or salt. All surfaces must be in contact with the cleaning solution for a full minute. Water-absorbent equipment (lifejackets, waders) should be soaked thoroughly to ensure complete contact.
DRY: If cleaning is not practical, after the item is dry to the touch, leave it to dry for at least another 48 hours before using in another freshwater body.
At this point, it is also extremely important to notify LSPA or DES of any suspicious algae in the area. Boaters from the Connecticut River should be especially cautious. Lake Sunapee’s Lake Hosts have been notified and will be sharing information with boaters.
Date published on web site:
07-12-2007
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