Offshore aquaculture of finfish: Big expectations at sea

Offshore aquaculture has gained momentum in recent years and the production of more marine farmed fish species is moving offshore. Initially, predictions of the advantages that offshore aquaculture would present over near shore farming were made without enough science-based evidence. Now, with more scientific knowledge, this review revisits past predictions and expectations of offshore aquaculture. The oceanographic features that define offshore and near shore sites are analysed and explained. Using Atlantic salmon (Salmo salar) as a case study we focused on sea lice, amoebic gill disease, and harmful algal blooms risk, as well as the direct effects of the oceanography on the health and physiology of fish. The operational and licencing challenges and advantages of offshore aquaculture are also explained in depth. Overall, moving aquaculture offshore is a risky and capital-intensive enterprise that still seems unadvisable. Regardless, the lack of space in sheltered areas will push new farms out to offshore locations. But if appropriate steps are followed, offshore aquaculture can be successful. First, the physical capabilities of the farmed fish species and infrastructure must be fully understood. Secondly, the oceanography of potential sites must be carefully studied to confirm that they are compatible with the fish species-specific physiological capabilities. And third, an economic plan considering the operational costs and licencing limitations of the site must be elaborated. This review will serve as a guide and compilation of this information for researchers and stakeholders.