Effectiveness of a Fishway for Restoring Passage of Colorado River Cutthroat Trout

Abstract

Little is known about the effectiveness of fishways for restoring passage to inland (nonanadromous) salmonids. We used PIT telemetry to evaluate the biological effectiveness of a vertical‐slot fishway constructed to restore passage of adult Colorado River Cutthroat Trout Oncorhynchus clarkii pleuriticus (CRCT) in a small Rocky Mountain stream. Our objectives were to assess (1) fishway efficacy (whether or not the fishway restored fish passage), (2) approach efficiency (the probability that a tagged fish encountered the fishway; an index of population use), (3) attraction efficiency (the probability that a fish near the fishway located its entrance), and (4) passage efficiency (the probability that a fish entering the fishway navigated successfully through it). To account for antenna detection probabilities and avoid biases that can result from simple, proportion‐based calculations, we used a variation of the Cormack–Jolly–Seber model to derive efficiency estimates. The fishway restored passage of adult CRCT to long‐vacant habitats. Approach efficiency was 4%; attraction and passage efficiencies were 100%. We conclude that fishways can effectively restore passage of inland salmonids, and we recommend that additional fishway monitoring studies be conducted to inform decision‐making and elucidate which designs and conditions will best facilitate passage. Received April 19, 2017; accepted September 26, 2017Published online November 6, 2017

Comparison of Methods to Verify Upstream Passage by Trout at Remediated Culverts in Four Rocky Mountain Streams

“…Generally, a fish detected in a stationary antenna's field is assumed to have passed (e.g., Hodge et al. ), but deploying multiple antennas, which was done here, helps to remove any doubt. Here, we focused on movement detected at the two inside antennas, which were common to all sites, but we observed that in two streams (Stream521 and Stream523), the two outside antennas detected the same number of individuals moving upstream as did the inside antennas.…”

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

“…Model‐averaged parameter estimates were used to quantify fishway efficiency for each species (Hodge et al 2017). The probability of entering the fishway was obtained from the downstream antenna (φ E ), and passage efficiency, the probability that a fish successfully ascended the fishway, was obtained from the upstream antenna (φ P ).…”

Attraction, Entrance, and Passage Efficiency of Arctic Grayling, Trout, and Suckers at Denil Fishways in the Big Hole River Basin, Montana

“…A comprehensive evaluation of fishway efficiency requires the systematic assessment of three distinct efficiency components (attraction, entrance, and passage) of approaching fish, any of which can reduce overall fishway efficiency (Bunt et al 2012(Bunt et al , 2016. However, previous studies have typically defined success rates by combining multiple efficiency components (Forty et al 2016;Hodge et al 2017), precluding assessment of each distinct component. "Approach" describes the number of fish that encounter a potential barrier and is an index of potential population use (Hodge et al 2017).…”

“…However, previous studies have typically defined success rates by combining multiple efficiency components (Forty et al 2016;Hodge et al 2017), precluding assessment of each distinct component. "Approach" describes the number of fish that encounter a potential barrier and is an index of potential population use (Hodge et al 2017). "Attraction efficiency" is the percentage of approaching fish that locate the fishway entrance, "entrance efficiency" is the percentage of attracted fish that enter the fishway, and "passage efficiency" is the percentage of entering fish that successfully pass (Cooke and Hinch 2013).…”