Contact Us


All News Releases By Date


EPA and the Federation of Fly Fishers sponsor international symposium on invasive algae

Release Date: 05/18/2006
Contact Information: Sarah Spaulding (303) 312- 6212,; Richard Mylott (303) 312-6654,

{5/12/2006} Denver -- Scientists, conservationists and policymakers from around the world will gather on May 15-16 in Bozeman, Montana at the Montana State University Campus to discuss the spread of the microscopic organism Didymosphenia geminata and its impacts on fisheries, tourism and regional economies. The alga, a diatom often referred to as “didymo,” can expand rapidly and commonly forms slime in rivers and streams. Didymo is creating nuisance blooms with greater frequency and is expanding its geographic range in North America, Europe and New Zealand.

“As an international community, we are concerned about the emerging problem of didymo blooms in streams and rivers," said Dr. Sarah Spaulding, US Geological Survey Ecologist. "Natural resource managers and recreationists are calling for action, yet we have few scientific and management recommendations to offer.”

“The damage that didymo has done to aquatic ecosystems in other parts of the world warrants our attention," said Karl Hermann, a specialist at the US Environmental Protection Agency. "By bringing experts together to share new data, our hope is to enhance our ability to effectively manage this nuisance species and protect watersheds, fisheries, and the economies that depend on them.”

Didymo is a concern because it has dramatic effects on aquatic organisms. Scientists observe that the thick, slimy stalks of didymo displace beneficial algae. The large masses also impact species composition and abundance of stream dwellers, including larval insects, which provide food for fish. Anglers are concerned that unsightly, slippery masses starve fish and foul lines. Water managers are concerned that the costs of removing thick growths from canals and filters will be high.

The symposium will feature a plenary session by Dr. Barry Biggs, National Institute of Water and Atmospheric Research, Christchurch, New Zealand. Dr. Biggs initiated a rapid response to the invasion and spread of didymo on the south island of New Zealand. International speakers from England, Canada and Iceland will also present information on the management of blooms in their countries.

The symposium is open to the media and the general public and will include scientific presentations, public discussion, and a field trip to an impacted site. Registered participants include representatives of tribes, state and federal agencies, consultants, non-profit fisheries organizations and academics from around the country. The program is posted at:

The event is cosponsored by the Federation of Fly Fishers and EPA and will be held in conjunction with the Western Division American Fisheries Society Meeting at Montana State University.

For more information on the biology of Didymosphenia geminata, see:

For more information, contact:
Sarah Spaulding
USGS/EPA Region 8
(303) 312-6212

Leah Elwell
Federation of Fly Fishers
(406) 222-9369