New Approach to Evaluate Barotrauma Susceptibility in Fish

Rapid decompression causing barotrauma on fish has been a major problem in many different countries. The swim bladder morphology plays an important role in determining the reaction of fish to decompression and the susceptibility to barotrauma. Thus, understanding the tensile properties of the swim bladder tissue can help determine the probability of mortal injuries due to rapid decompression. A testing apparatus was designed to obtain the stress-strain curve of a swim bladder tissue sample. This information would allow the development of a model to predict the resistance of a swim bladder to volume expansion. This new approach was tested using latex balloon samples, which were stretched until rupture. A stress-strain curve was gathered and used to calculate the pressure necessary to fracture a balloon during air filling, considering its geometry and tensile properties. Then, balloons were inflated measuring the pressure until rupture, and the values were compared to those estimated using the model. The results showed a potential use of the model to determine the swim bladder capacity to hold the pressure increased by volume expansion during decompression, without fracturing. Thus, this could help reduce barotrauma injuries due to the swim bladder rupture.