Optimizing volume estimation in aquaculture sea cages: A comparative study of calculation methods and sensor placement

Due to intensified environmental challenges and industry growth, salmon aquaculture is expanding into regions with stronger currents and higher waves. This can expose sea cages to the elements and result in pronounced cage deformations. Such deformations diminish net volume, potentially jeopardizing fish welfare and survival. A prevalent approach to gauging these deformations involves attaching pressure sensors at strategic locations on the cage. This study presents a comprehensive analysis of methods for calculating the volume of deformed aquaculture cages, categorizing them into two main approaches. The first approach involves dividing the cage’s surface into triangular sections to calculate the overall volume. The second approach dissects the cage’s interior into distinct segments for individual volume assessments. The effectiveness of these methods was tested on a cage exposed to extreme wave and current conditions, followed by simulations to investigate optimal sensor configurations for precise volume determination. Among the evaluated methods, the Cylinder with Cone method is praised for its simplicity, whereas the Signed Volume and Projection methods emerge as the gold standard for accuracy. A pivotal finding is the imperative of sensor placement for precision in volume calculations, with an optimal configuration comprising four sensors on the rim and one at the bottom centre. For heightened precision, a distribution of sensors between the rim, bottom centre, and cage side is endorsed in tandem with the Signed Volume or Projection method. •Volume calculations accurate even with significant deformations and easy to implement.•Measurements of volume reduction in cages using pressure sensors are demonstrated.•The sensor count required for volume estimation is ascertained from simulations.