Modelling the response of offshore aquaculture fish pens to environmental loads in high-energy regions

Abstract

Offshore aquaculture is a burgeoning sector, but operating in offshore environments can be difficult, especially in areas with high energy conditions such as strong currents and waves. The purpose of this study was to understand the effects of these environmental loads on slender gravity salmon fish cages, which are commonly used in offshore aquaculture operations. By simulating the responses of the cages to different load conditions, this study aims to provide useful data for the design of anchors and other structural elements of offshore aquaculture operations. A structural Finite Element Method (FEM) model was used to simulate the responses of the salmon cages to environmental loads. An extensive sensitivity analysis was conducted, examining the responses of the salmon model to current-only and combined current and wave scenarios under various conditions. These conditions included different magnitudes and angles of attack for the current and waves. The results showed that symmetrical orientations of the cages experienced lower anchor line tensions than those with lesser symmetry. In the farm with the highest number of cages, the anchor line tension reached a value of 2.9 MN. This study provides valuable data for the design of offshore aquaculture anchors, particularly in high-energy regions where environmental loads can be severe, through a series of large-scale sensitivity analyses, specifically for the purpose of determining the largest expected anchor loads.