Numerical simulation of net cage and an alternative method to estimate the remaining volume

The deformation caused by waves and current in an aquatic environment significantly impacts the remaining volume of a net cage. Its fluctuations in magnitude could pose a potential threat to the well-being of cultivated species. There's a critical need for a simple, cost-effective solution to monitor cage deformation in real-time. This study proposes a depth-based method, utilizing just two depth meters attached to the cage's floating collar and tube sinker, to estimate the remaining volume. Comparing to the experimental measurements from previous studies, this method demonstrates satisfactory accuracies. Under current-only and waves-current conditions, the estimation differences are around 11.6% and 23%, respectively. In contrast, when compared to commonly-used volume-based methods, the differences are approximately 1.8% and 9.5%. Despite a tendency for overestimation when the mean cross-sectional area deviates from the original top or bottom area of the cage, this method remains a feasible alternative. Its practicality highlights its potential as an efficient means of monitoring cage deformation.