Author(s): Alfredo Schiavon; Ambra Alderighi; Michele Spairani; Alessandro Candiotto; Daniel Nyqvist; Davide Bonetto; Enrico Pini Prato; Claudio Comoglio

Linked Author(s): Claudio Comoglio

Keywords: Larinier fishway; PIT telemetry; Swimming performance; River connectivity

Abstract: Anthropogenic barriers fragment river networks worldwide, restricting fish movement and altering ecological processes. Technical fishways are widely used to restore connectivity, yet their performance for the many non- salmonid fish species remains poorly u nderstood. In a PIT telemetry study we investigated the upstream passage along a Larinier super active baffles fishway of five fish species in the Upper Tanaro River (Italy): Italian chub (Squalius squalus), barbel (Barbus spp.), minnow (Phoxinus sp.), Italian riffle dace (Telestes muticellus), and bullhead (Cottus gobio). Barbel and Italian chub achieved passage success rates of 47% and 54%, respectively, whereas none of the other species were able to negotiate the fishway under the tested hydraulic conditions. Italian chub progressed through the structure substantially faster than barbel, reflecting contrasting behavioural patterns and swimming strategies in turbulent flow. These findings indicate that Larinier super active baffles fishways, a relatively cheap and easy to maintain retrofit solution to restore connectivity at low-head barriers, operating at a 15% slope may have a limited efficiency for some fish species, and that interspecific differences in swimming capacity and behaviour strongly influence passage outcomes. Effective fishway design therefore requires consideration of fish ecological traits, and behavioural diversity to accommodate the full range of species present in riverine communities.

DOI: https://doi.org/10.64697/iahr.proc.ise2026.abs.195

Year: 2026