From inshore waters to the deep blue sea, and from tradition to modernity, deep and distant sea aquaculture is not simply a matter of moving fish cages to offshore areas. Instead, it is a complex systems engineering involving interdisciplinary integration, including equipment engineering, marine environment, bio-ecology, and information management.

The selection of aquaculture sites requires a comprehensive consideration of the natural and economic feasibility of the cultured organisms, the performance of facilities and equipment, as well as marine environmental conditions, and it serves as the foundation for carrying out deep and distant sea facility aquaculture activities.

Deep-sea aquaculture facilities vary in structural types and specifications, and the natural conditions of different sea areas also differ. Therefore, when selecting sites for deep-sea aquaculture, the technical indicators and standards used will vary significantly. It is necessary to combine the cultured organisms with the performance conditions of deep-sea aquaculture facilities and equipment, screen the sea space conditions suitable for the growth of cultured organisms and meeting the safety requirements of the equipment, so as to carry out deep-sea aquaculture activities with economic benefits.

For open-system deep-sea aquaculture, the environment where the cultured organisms reside is the external environmental conditions themselves. Therefore, there exists a mutual influence between deep-sea facility-based aquaculture and its surrounding environment. Meanwhile, certain interactive effects also occur among the aquaculture facilities. During the site selection process for deep-sea aquaculture, all potential interactions and their impacts on deep-sea aquaculture should be evaluated, including the environmental impacts of deep-sea aquaculture activities, so as to minimize threats, hazards, and overexploitation. The key factors to consider when selecting a site for a deep-sea aquaculture project mainly include three aspects: factors for the healthy growth of cultured organisms, factors for the safe operation of aquaculture facilities, and other relevant factors.

I. Factors for the Healthy Growth of Cultured Organisms

Deep-sea facility-based aquaculture areas must have good water quality. The water quality of the relevant sea areas should not only be free from industrial pollution but also meet the biological needs of the cultured organisms. Specific factors include dissolved oxygen, pollutants, temperature, salinity, pH, pathogens and pathogenic factors, light and transparency, etc. It is required that the amount of particulate suspended matter in the aquaculture water can be controlled within a certain range, and the probability of water eutrophication and the occurrence of diseased organisms is relatively low. A certain water flow rate is necessary to ensure sufficient water exchange; however, an excessively high flow rate will exert pressure on the cultured organisms and the facility equipment.

II. Factors for the Safe Operation of Aquaculture Facilities

When selecting a site for a deep-sea aquaculture project, it is necessary to consider not only the optimal sea area water quality conditions required by the cultured organisms but also the impact of the marine environmental conditions on the installation of aquaculture facility equipment, barges, and other related aspects. The finalization of deep-sea aquaculture facility specifications, the design and construction of mooring systems, and the selection of auxiliary vessels must all take into account the following factors: water depth or the water depth at the selected site (e.g., seabed topography and contour lines), current speed and direction, wind force, waves, seabed (e.g., seabed sediment type), and the incidence of tropical cyclones.