Introduction

Aquaculture is the fastest growing food producing sector in the world. Population increase, food security, employment, stresses on the fresh water resources and uncertainty associated with wild fish stocks are key parameters driving the demand for aquaculture expansion. However, limitation in adequate waters in the coastal and near-shore sites for aquaculture and the interactions within and from other coastal services, forces the fish farming industry to move further offshore. Offshore aquaculture can assure increased water quality and oxygen supply, which improve production efficiency and the quality of fish. However, moving further offshore presents a new set of challenges i.e., withstanding severe weather conditions, provide safe and economic functioning of the aquaculture systems (Buck, 2017).

The successful design of an offshore aquaculture system concerns among others the determination of the net characteristics (i.e., shape, materials, twine number etc.) and the materials used for nets. A cage system behaves dynamically since the wave loads affecting the cage frame are transferred to the net. The influence of environmental loads can cause failure in nets (Kristiansen & Faltinsen, 2012; Liu et al., 2021; Qiao, 2021). In addition, polymer materials with improved properties, lighter, with higher strength, impact strength and abrasion

resistance have already been adopted as well as copper nets (Kalantzi et al., 2016, Mejri et al., 2017).

The present work aims at evaluating the wave forces on different types of net systems suitable for offshore aquaculture systems and at assessing the impact of marine environment on the polymeric netting materials.