Multispecies Fish Passage Evaluation at a Rock‐Ramp Fishway in a Colorado Transition Zone Stream

• Published in: North American Journal of Fisheries Management
• Main Authors: Richer, Eric E., Fetherman, Eric R., Krone, Elizabeth A., Wright, F. Boyd, Kondratieff, Matt C.
• Other Authors: Colorado Parks and Wildlife
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2020
• Subjects: Catostomus catostomus; Longnose sucker
• Online Access: http://dx.doi.org/10.1002/nafm.10516; https://onlinelibrary.wiley.com/doi/pdf/10.1002/nafm.10516; https://onlinelibrary.wiley.com/doi/full-xml/10.1002/nafm.10516; https://afspubs.onlinelibrary.wiley.com/doi/pdf/10.1002/nafm.10516

Abstract Stream habitat fragmentation caused by manmade structures is ubiquitous in Colorado, creating a need for passage solutions that accommodate multiple fish species. This study tested the effectiveness of a rock‐ramp fishway for passing nine fish species with a range of swimming abilities. The target species for the fishway design included Brassy Minnow Hybognathus hankinsoni (weakest swimming), Longnose Dace Rhinichthys cataractae , Longnose Sucker Catostomus catostomus , and Brown Trout Salmo trutta (strongest swimming). Testing included a 46‐h enclosure study and 3‐month extended study, during which fish passage was evaluated using PIT tags. All of the species exhibited successful passage through the fishway during the enclosure study, but movement probabilities varied by species. Five species were not detected at the fishway during the extended study, possibly due to issues with attraction flows, entrance conditions, or motivation. Hydraulic conditions within the fishway were also evaluated. Roughness elements maintained a benthic, low‐velocity zone across a range of flows, even when surface and depth‐averaged velocities surpassed the design criteria for the weakest swimming species. The methods from this study could be replicated at other locations to evaluate design criteria (e.g., slope, capacity, roughness, and configuration) and performance for a variety of fish species and fishway types.