Many Australian native fish species undertake downstream migrations, which expose them to passage through infrastructure such as weirs and hydropower facilities.  The rapid decompression may cause barotrauma through rapid expansion of their swim bladder and release of dissolved gas in the blood.

Specialist, customised barochambers have been designed, built, tested and implemented for the purpose of understanding the upper limits of decompression that Australian fish species can tolerate during passage through water infrastructure . NSW Fisheries researchers have successfully utilised the barochambers to derive mortality and injury versus pressure curves.

These specialist barochambers were designed and built at the University of New South Wales. They are relatively large (700mm x 400mm), have large flat glass windows for high speed video of the barotrauma and are capable of achieving pressure changes from up 200kPa to as low as 10kPa in under 0.5 seconds.   Further, the barochambers needed to be contained in a mobile laboratory to be taken to various field and laboratory stations. 

Apart from the rapid pressure changes to incite barotrauma, the chambers could also gradually acclimatise fish to specific pressures over extended periods while circulating water to ensure that dissolved oxygen levels are were maintained.

This paper presents how the design criteria were developed by balancing the requirements of fisheries experts with the hydraulic practicalities and costs limitations.  The design, component selection, instrumentation, bespoke control software and the results of performance testing are presented along with further discussion of design alternatives including cheaper and more expensive chambers.