Author(s): Lorena B. Nogueira; Higor A. A. G. Vieira; Breno A. Magalhaes; Dieimys S. Ribeiro; Liandro Rosa; Juliano Mafra; Guilherme Ferraz; Andrey L. F. De Castro; Carlos B. Martinez; Luiz G. M. Silva

Linked Author(s): Luiz G Martins da Silva

Keywords: Total Dissolved Gas; Gas Bubble Disease; Neotropical fish; Experiments

Abstract: Fish mortality near hydropower facilities is increasingly linked to total dissolved gas (TDG) supersaturation, which can cause gas bubble disease (GBD) in aquatic organisms. While TDG thresholds are documented for temperate species, data for Neotropical fish remain unknown . This study introduces a mobile TDG laboratory designed to expose fish to controlled supersaturation levels and reports preliminary findings for Prochilodus nigricans. Acute exposure experiments were conducted under four TDG treatments (control, 115%, 125%, and 130%). All exposed individuals exhibited GBD-related injuries, including emboli in fins, gills, and internal organs. Mortality occurred within 2–4 hours at 125% and 130%, while fish at 115% did not die within the 24h exposure, but showed chronic lesions. These results suggest Neotropical species may be more sensitive to TDG than previously thought, highlighting the need for region -specific thresholds in environmental regulation and hydropower planning.

DOI: https://doi.org/10.64697/iahr.proc.ise2026.abs.237

Year: 2026