Thesis Title: Assessing the station holding ability of three benthic fishes exposes to flow augmentation: implications for species at risk.

Author: Taylor (Macs) MacLeod


Flow augmentation forces Plains Sucker in the Milk River to adopt more efficient station holding mechanisms, which must be energetically costly as they are not maintained year-round. The station holding ability of Milk River Plains Sucker was measured using a Brett-style swim tunnel respirometer, and the results were compared to other catostomid species in the Milk River and to Plains Sucker caught in water bodies that remain unmodified year-round. Milk River Plains Sucker maintained a significantly higher estimated marginal mean failure velocity (p < 0.0001) during augmentation (June-July) compared to natural flows (September-October). Catostomids in Milk River exhibited varying degrees of response; from no change in response to augmentation (Longnose Sucker, p = 0.5) to a significant shift (Plains Sucker and White Sucker p =
0.0001). Plains Sucker from unmodified water bodies demonstrated at most a minor change in performance between sampling periods (Battle Creek, p = 0.041; Caton Creek p = 0.068). The substantial energetic input into station holding may result in life history trade-offs impacting the populations’ continued existence in this part of its native range.


Posted in Conservation of Freshwater Fishes, Restoration and Reclamation, Species at Risk and tagged , .