Author(s): Daniel S. Hayes; Erkin Karimov; Pieterjan Verhelst; Otabek Omonov; Andrea Funk; Ianina Kopecki; Johan Coeck; Bakhtiyor K. Karimov; Jan De Keyser; Fazliddin Muhammadiyev; Matthias Schneider; Bernhard Zeiringer; Bertalan Alapfy; Justine Carey; Carina Seliger; Falko Wagner; Tom Roessger; Martin Schletterer

Linked Author(s): IANINA KOPECKI, Matthias Schneider, Falko Wagner, Daniel Hayes

Keywords: Snowtrout; Snow barbel; Schizothoracinae; Macroinvertebrates; Water management; E-flow; Fish protection facilities; Syr Darya River Basin

Abstract: Central Asian freshwater ecosystems face increasing pressure from anthropogenic activities, including the expansion of water infrastructure for irrigation and hydropower. In addition to these challenges, knowledge of the biogeography and ecology of aquatic organisms in the region remains limited. This study, conducted as part of the “Hydro4U” project , aims to address these knowledge gaps by investigating regional freshwater biodiversity as well as habitat use and seasonal migration patterns of a key fish species in Central Asia. We conducted fish surveys across >100 sites in over 80 rivers, complemented by environmental DNA sampling at a subset of sites, to assess large-scale biodiversity patterns. Additionally, we studied longitudinal zonation of benthic macroinvertebrate communities in the Shakhimardan River Basin. The key fish species, Schizothorax eurycephalus, was studied in detail to understand its migration patterns and seasonal habitat preferences. We employed radio telemetry to track the seasonal movements of tagged individuals over a two-year period between the Shakhimardan River and its headwaters, the Koksu and Aksu Rivers. Our results reveal significant spatial and altitudinal variability in aquatic biodiversity. Macroinvertebrate communities showed clear longitudinal zonation, with abundance and composition varying along the altitudinal gradient. Seasonal migration patterns of tagged fish indicate that S. eurycephalus use tributaries like the Koksu River as winter refugia, likely due to warmer water temperatures. These findings provide valuable insights into the ecology of Central Asian river systems and a baseline for biomonitoring, ecohydraulic studies, and Red List assessments.

DOI: https://doi.org/10.64697/iahr.proc.ise2026.abs.291

Year: 2026