A barotrauma chamber for the systematic assessment of barotrauma-related injuries in potamodromous European fish species

Fish passing through hydropower turbines can suffer barotrauma due to characteristic rapid pressure drops. To investigate the effects of different pressure gradients on fish, a barotrauma chamber was developed to replicate pressure conditions in European run-of-river power plants. The chamber operates within a pressure range of 14 to 450 kPa, generating pressure drops of a duration of less than 0.1 s via a fast-moving piston. With a 70-litre capacity, it accommodates ∼70 juvenile or 2–3 adult fish, allowing their simultaneous exposure to in-situ measured pressure curves. The chamber also facilitates pre-acclimation to depth conditions and anaesthesia before testing. The pre-defined pressure curves take into account the air volume in the chamber, including that within the swim bladders of the fish, which may have a significant impact on the results. This chamber facilitates controlled investigations of barotrauma impacts on European fish species, thereby enhancing comprehension of potentially harming turbine passage effects.