Cooperative Fish and Wildlife Research Units Program: South Dakota
Education, Research and Technical Assistance for Managing Our Natural Resources

South Dakota Project

Influence of an Invasive Diatom Didymosphenia geminata on Food Availability and Brown Trout Energetics in Rapid Creek, South Dakota

September 2007 - June 2011


Participating Agencies

  • South Dakota Department of Game, Fish and Parks

Didymosphenia geminata (hereafter referred to as ‘Didymo’) is a relatively large, easy-to-identify diatom that historically occurred in low productivity streams and lakes at northern latitudes. Since the mid-1980s, the geographic range of Didymo has expanded in many regions of Europe and North America. In many cases, these populations have taken on characteristics of an invasive species – often forming large, nuisance growths that cover stream benthos. In 2002, Didymo was reported from the Rapid Creek drainage in the Black Hills of western South Dakota. Rapid Creek represents an important brown trout Salmo trutta fishery for South Dakota, particularly below Pactola Reservoir – a reach that has long been recognized as a ‘blue ribbon’ catch-and-release fishery.

Research Publications Publication Date
James, D. A., S. H. Ranney, S. R. Chipps, and B. D. Spindler. 2010. Invertebrate composition and abundance associated with Didymosphenia geminata in a montane stream. Journal of Freshwater Ecology 25(2):235-241. | Download June 2010
James, D. A., J. W. Wilhite, and S. R. Chipps. 2010. Influence of drought conditions on brown trout biomass and size structure in the Black Hills, South Dakota. North American Journal of Fisheries Management 30:791-798. | Download June 2010