Efficiency of a nature‐like bypass channel for sea trout (Salmo trutta) ascending a small Danish stream studied by PIT telemetry

Abstract

– Upstream passage of adult sea trout (Salmo trutta) in a nature‐like bypass channel was investigated in the Tirsbæk brook, Denmark, in autumn and winter 1999/2000. Sea trout were caught by electrofishing up‐ and downstream of the weir at which the bypass was situated. Fish were tagged with passive integrated transponder (PIT) tags and released downstream of the weir. Automatic PIT‐tag logging stations were positioned downstream, in the lower part, and at the upstream exit of the bypass to investigate the passage success of the fish. The bypass was neither size‐ nor sex‐selective in the size ranges investigated. The majority (68%) of fish approached the bypass at night. Over 90% of tagged upstream‐searching fish located and entered the bypass channel, but only about half of them passed through. The inefficiency is suggested to be because of a combination of the length of the bypass channel and inadequate flow in the bypass channel.

The Canal da Piracema at Itaipu Dam as a fish pass system

“…These fish passes have many advantages over traditional fish pass systems, because their generally heterogeneous structure offers several velocities and depths for a great variety of species and fish sizes. In addition, they provide habitats for them to live in (Lucas & Baras, 2001;Aarestrup et al, 2003), as is the case of the Canal da Piracema (specifically the Bela Vista River).…”

“…Thus, the attraction efficiency (not evaluated in the present study) must be quantified, and then the passage efficiency, which together will define the efficacy of a fish pass system as a whole (Aarestrup et al, 2003). The abrupt reduction in the fish species abundance from downstream to upstream, even for migratory species, indicates that the Canal da Piracema is acting selectively.…”

Changes in particulate organic matters and plankton populations in nature-like fishways: role of nature-like fish ways in water treatment

“…These nature-like fishways are built with diverse materials, such as large wood debris, boulders, and riparian vegetation, imitating natural stream geomorphologic conditions (Bretón et al, 2013). Due to their heterogeneous structure, compared with conventional fishways, nature-like fishways offer a greater variety of water velocities and depths, making them amenable to a wider range of fish species and sizes (Aarestrup et al, 2003).…”

A barrier to upstream migration in the fish passage of Itaipu Dam (Canal da Piracema), Paraná River basin

“…Passage success through upstream fishways depends primarily on two factors: i) the capacity of the fishes to find and enter the system, and ii) the capacity of the fishes to pass through the length of the system (Aarestrup, 2003;Bunt et al, 1999Bunt et al, , 2011Castro Santos & Haro, 2010). Although the efficiency of the Canal da Piracema has not been evaluated as a whole, various migratory species, but specially P. lineatus and L. elongatus are abundant in the Bela Vista River (Makrakis et al, 2007b).…”

“…Fish passage evaluation by PIT telemetry is gaining popularity (Castro-Santos et al, 1996;Aarestrup et al, 2003;Teixeira & Cortes, 2007) and it can be a highly effective and low-cost methodology for studying movements of fishes of varying sizes and morphologies (Prentice et al 1990;Franklin et al 2012). It is particularly useful for quantifying movements through confined structures like fish passages (Castro-Santos et al, 1996).…”