Assessing Responses of Fish to Habitat Enhancement in Barrenlands Streams of the Northwest Territories

Abstract

We examined the effectiveness of three fishpasses (two gabion‐style pool–weir fishpasses and one nature‐like choke‐and‐pool fishpass) at enhancing connectivity among three small, headwater lakes as part of a fish habitat compensation project in the Barrenlands region of the Northwest Territories. We quantified fish attraction and passage efficiency of fishpasses using PIT antennae, and compared fish use of fishpasses to reference streams using visual and electrofishing surveys for 1 year before and 2 years after their construction. We did not detect, observe, or capture any fish in either of the gabion‐style pool–weir fishpasses during the first year after construction, and these two fishpasses were subsequently retrofitted to improve their hydraulic performance. After retrofits were completed, we still did not detect any tagged fish (≥150 mm) migrating through the two fishpasses using PIT telemetry, but identified some small fish moving downstream through these fishpasses during visual and electrofishing surveys. Conversely, we detected tagged Arctic Grayling Thymallus arcticus migrating upstream and downstream through the nature‐like choke‐and‐pool fishpass during both postenhancement years, and also encountered fish throughout this fishpass during visual and electrofishing surveys. Compared with reference streams, gabion‐weir fishpasses limited fish movement and use even after modification, whereas the nature‐like fishpass successfully facilitated fish movement and use. We recommend against using gabion‐style pool–weir fishpasses in Barrenlands headwater lake–stream systems, particularly when stream flow is limited, and suggest future projects aimed at enhancing lake–stream connectivity explore nature‐like fishpass designs in an experimental management framework.

Partial dam removal restores passage for a threatened salmonid

“…Changes in water depths have been associated with large‐scale fish movements (Alabaster, ; Egglishaw & Shackley, ; Taylor & Cooke, ), and are often an important predictor of the probability to pass fishways (e.g., Cahill et al, ; Mallen‐Cooper & Brand, ). The probability to pass was positively correlated to water depth.…”

Arctic Grayling Movements through a Nature‐Like Fishpass in Northern Canada

“…Indeed, Arctic Grayling often spawn in small streams during freshets (Northcote 1995;Stewart et al 2007), the onset of which is rapid, variable in timing among years, and of short duration (i.e., 5-10 d; Jones et al 2003a;Courtice et al 2014). Moreover, field observations suggested that Arctic Grayling appear in streams and fishpasses almost immediately after the freshet begins (Cahill et al 2015).…”

“…To minimize the impacts of tagging mortality on our analyses, we analyzed passage events only from individuals that were detected in the M2S fishpass (as opposed to all tagged fish). Tagged Arctic Grayling that were detected as passing the fishpass were assumed to have been exposed to all conditions during the period of availability because M1L and M2L were small and because no tagged fish were detected as being present in or migrating through the M1S and M3S fishpasses (Cahill et al 2015). Environmental conditions associated with fish passage events were designated as "used," and we then created a matrix of available and used conditions for each fish.…”

“…Subsequent evaluations of the three fishpasses showed that only a single, nature-like choke-pool fishpass allowed for fish movement (Courtice et al 2014;Cahill et al 2015). Cahill et al (2015) evaluated the performance of the nature-like fishpass for Arctic Grayling and found that the upstream attraction and passage efficiencies were higher than the downstream attraction and passage efficiencies. The objective of the present study was to investigate factors associated with Arctic Grayling movements through the successful fishpass.…”

Rainbow Trout Migration and Use of a Nature‐Like Fishway at a Great Lakes Tributary

“…Although nature-like fishways appear to be the most effective and promising mitigation strategy for fish passage (Franklin et al 2012;Steffensen et al 2013), there are no known studies of Rainbow Trout passage for this type of fishway design. In comparison, one study was conducted with Atlantic Salmon Salmo salar (Nyqvist et al 2017), one was conducted with Brook Trout Salvelinus fontinalis (Landsman et al 2018), five were conducted with Brown Trout Salmo trutta (Aarestrup et al 2003;Greenberg 2005, 2007;Tummers et al 2016;Dodd et al 2017), and 11 studies reported efficiency values for 43 nonsalmonid species at nature-like fishways (Schmutz et al 1998;Greenberg 2005, 2007;Franklin et al 2012;Steffensen et al 2013;Cahill et al 2015;Bunt et al 2016;Kim et al 2016;Landsman et al , 2018. Total efficiencies also varied greatly among these studies and ranged from 7% to 97% for salmonids alone, demonstrating both the design-specific and species-specific characteristics of fishway performance.…”