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DEP Warns Against the Spread of Rock Snot

April 8, 2008

Rock Snot, an algae that forms massive mats in streams, arrived on the East Coast in 2007 and has been found in the upper (NY) Delaware River. The Department of Environmental Protection asks anglers, boaters and other water enthusiasts to be vigilant in cleaning their equipment in order to stop the spread of this invasive species.

Rock Snot (also known as Didymo) is native to the alpine regions of Europe, Asia, and western North America. Rock snot has been causing problems with its massive blooms in the western US for about a decade. In the summer of 2007 this highly invasive algae was found in rivers on the East Coast for the first time.

Rock Snot is generally drab in color. It can be light grey, brown, white, or pale yellow and attaches to rocks or plants. It either forms large mats closely resembling algae blooms or forms long streams that look similar to toilet paper.

In order to avoid spreading Rock Snot to a new stream or river, all equipment such as waders, clothing, boats, fishing gear and any other object that has been in contact with the water should be cleaned before traveling to a new site. Use the following steps:

1. Remove any natural debris from your equipment before packing up and leave the debris on the shore at the site.

2. Soak and scrub nonporous items such as rubber waders and buckets for at least one minute.

3. Let porous items, such as felt-soled boots or clothing, soak for a minimum of 30 minutes.

  • To clean your equipment use either a solution of bleach and hot water, salt and hot water, or dish detergent and hot water. The hotter the water, the more effective the cleaning will be.
  • Do not use a hose to clean your equipment; this may result in the Rock Snot entering a storm drain and thus entering a stream.
  • If cleaning is not practical, dry or freeze the items completely, then let set for at least an additional 48 hours.
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Department of Environmental Protection
P. O. Box 402
Trenton, NJ 08625-0402

Last Updated: April 10, 2008