Rock snot showed up this winter, invasive aquatic algea (didymo) no current methods for controlling it.


Didymo (Didymosphenia geminata): a threat to trout streams. Your help is needed to prevent the spread of didymo. This highly invasive freshwater alga (also called "rock snot") has now been found in popular trout streams located a number of northeastern states (New Hampshire, Vermont, New York, Pennsylvania, Maryland, West Virginia and Virginia). Didymo has the potential to alter food webs and degrade habitat in many Connecticut trout streams.

Didymo is typically found in shallow streams with rocky substrate. Thought to be native to northern regions of Europe, Asia and North America, didymo originally was found only in cold, clear, low-nutrient waters.

Didymo's geographical and ecological ranges have been expanding, and now also include warmer and more nutrient-rich waters. The occurrence and intensity of blooms are also increasing. It is currently unclear why.

The microscopic didymo cell produces a stalk to attach to the substrate. During blooms, didymo can produce large amounts of this stalk material, forming thick mats of cottony material that feels like wet wool on the bottoms of rivers and streams. These mats can potentially smother aquatic plants, mollusks, destroy invertebrate and fish habitat, and impact existing food webs.

Anglers are considered an important vector responsible for the recent spread of didymo. The microscopic cells can cling to fishing gear, waders (felt soles can be especially problematic), boots and boats, and remain viable for months under even slightly moist conditions.

What you can do to prevent the spread of didymo:

Before leaving the launch:

CLEAN: remove any visible mud, plants, fish or animals before transporting equipment.
DRAIN: eliminate water from equipment, such as a live well, before transporting.

At home or prior to your next launch:

DRY: anything that comes into contact with water (boats, trailers, anchors, propellers, fishing equipment, clothing, dogs, etc.) for a minimum of one week during hot/dry weather and four weeks during cool/wet weather.

If drying is not possible:

Wash with hot water (preferably high pressure).
Dip equipment into 100% vinegar for 20 minutes prior to rinsing.
Use a 1% salt solution (1oz. per gallon) or soap and hot water (Lysol, boat soap, etc.) for 10 minutes prior to rinsing.