Didymo is a single‐celled, microscopic alga that can produce a stalk. Recently, enormous stalk production by this alga has resulted in visible blooms of Didymo in rivers worldwide and has generated concern because of possible impacts on the salmonid fish of these rivers. The Discovering Didymo Distribution project (D3) is Canada‐USA collaboration that is being piloted along the eastern slopes of the Rocky Mountains in Alberta and in North Carolina and the southern Appalachians.


The data collected by volunteers through this project will be used to determine where Didymo is located, what rivers it does and does not form blooms, and explore hypotheses about what physical, chemical, or human factors influence its presence and the formation of blooms.

Volunteers participating in this project receive a sampling kit and training on how to collect and preserve samples and record their observations. To collected potential Didymo observations, participants are asked to use EpiCollect5, a free online citizen science application. EpiCollect5 allows us to build a crowdsourced database of potential Didymo observations containing data scientists can use, including maps and photos, as well as allow participating anglers and citizen scientists to learn where Didymo is present or absent.

Volunteers are encouraged to sample their favourite rivers AND other rivers or small creeks where fish may or may not be present. Algae is scraped from rocks using standardized methods and stored in a tube provided in the sampling kit. Other observations are recorded either using a datasheet or on a smartphone through the EpiCollect5 app and the sample is dropped off at drop‐off stations in Calgary, Lethbridge, Rocky Mountain House, or Red Deer. All samples will then be shipped to the University of Calgary for analysis. The data collected through this project will be available online through the Trout Unlimited Canada website. Sampling instructions are provided in each kit and also provided here. Instructions for using EpiCollect5 as well as a paper datasheet are also included in kits or downloadable here.

For a map of Didymo observations in Alberta following the 2016 season, click here.

What’s Next?

Although this project is being piloted in Alberta and North Carolina, the project team plans to expand to other areas of North America in the coming years.

Partners and Sponsors

This project is a unique collaboration between Trout Unlimited Canada and Trout Unlimited in the USA. We are also working with the University of Calgary and North Carolina State University with additional support and advice from Fisheries and Oceans Canada. In Alberta, the project is financially supported by the Alberta Conservation Association. Clearwater County, the Oldman Watershed Council, Red Deer River Watershed Alliance, the Fishin’ Hole, and TC Outfitters are helping with collecting samples from volunteer participants.