Fisheries~Didymo Project

This project was the subject of my master’s thesis on the implications of nuisance algae (Didymo) for rainforest stream food webs (Kootenai River basin, Montana-British Columbia).

  • Didymosphenia geminata is an algae that can cover entire streambeds.
  • Didymo is relatively easy to treat, but it’s unknown whether it decreases the amount of invertebrate prey for fishes.
  • I worked to determine if Didymo alters stream food webs and impacts native fishes such as Bull Trout, Redband Trout, and Slimy Sculpin.
  • While Didymo did seem to impact invertebrates, it did not affect the diet, condition, or growth of native fishes.
Quantitative stream food web in Bear Creek near Libby, MT

Frequent Electrofishing & Trout Growth

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Shocking Ramsey Creek near Libby, MT.

Sometimes we want to sample fish multiple times in a year to see how growth, condition, or diet changes over time. Very few studies have addressed how often fish can be captured and handled before there are negative effects on their growth. I am using data from my master’s work on Bear Creek to see if increased handling of trout led to decreased summer growth.

Publications & Reports

Clancy, N.G., J. Dunnigan, and P. Budy. 2022. Relationship of trout growth to frequent electrofishing and diet collection in a headwater stream. North American Journal of Fisheries Management.

Clancy, N.G., J. Brahney, J. Dunnigan, and P. Budy. 2021. Effects of a diatom ecosystem engineer, Didymosphenia geminata, on stream food webs: implications for native fishes. Canadian Journal of Fisheries and Aquatic Sciences.

Clancy, N.G., J. Brahney, J. Curtis, and P. Budy. 2020. Consequences of Didymo blooms in the transnational Kootenay River basin. A report to BC Parks from the Department of Watershed Sciences at Utah State University, Logan, UT, USA.

Project Partners: Janice Brahney (Utah State University), Phaedra Budy (USGS/Utah State University), Jim Dunnigan (Montana Fish, Wildlife & Parks)
Project Funders: British Columbia Ministry of the Environment – BC Parks; U.S. Forest Service; Utah State University Dept of Watershed Sciences and Ecology Center
Acknowledgements: Jon McFarland, Ryan West, Marshall Wolf, Chris Clancy, Mike Young, Gary Thiede, Jay DeShazer, Ryan Sylvester, Chuck Hawkins, Jared Lampton, Jordan Frye, Brian Stephens, Monty Benner, Brett Roper, Mike Hensler, Jeff Burrows, Greg Andrusak, Joe Thorley, Murray Pearson.