The water area of deep and open sea aquaculture is far from the coast and deeper, so the natural risk of sea state is large and there are many uncertain factors. Therefore, deep and open sea aquaculture is a weak industry, and its risks are mainly reflected in the following aspects.
1．Marine Natural Risks
Compared to offshore aquaculture, deep and open sea aquaculture is far away from land and faces a more complex meteorological and hydrological environment, with frequent marine meteorological disasters and greater natural risks, including storm surges and huge waves caused by typhoons and tornadoes, which can cause devastating or even destructive blows to the net cage aquaculture system. In addition, fierce animals such as sharks can cause a certain degree of damage to the net of the cage, leading to escapes and reduced production of farmed fish.
2．Facility and equipment risk
Coastal aquaculture technology is relatively mature, but deep and open sea aquaculture equipment and technology started late, and the reliability and service life of equipment need to be verified. Specifically, there is a lack of intensive breeding equipment with equal emphasis on reliability and economy, especially breeding feeding equipment, monitoring instruments and mooring technology, which need to be improved. It will take a longer time to accumulate the hydrological and sediment data monitoring in the far-reaching sea areas.
3．Risk of fish net materials
Existing breeding cage net materials are mainly nylon material, high weight polyethylene material and PET material developed in recent years. Their main weakness is low strength, easily attached organisms which need regular cleaning (at least once a month), short life span, etc. This is not conducive to the use of deep and open sea aquaculture requirements. According to past experience, we have to take the road of using metal net to effectively solve the historic problem of breeding reliability.
4．Remote O&M management risks
On the one hand, the large-scale and intensive production mode is mainly adopted in the deep and open sea area, which requires high controllability of production. However, the complex and changeable environment in the deep and open sea area makes real-time monitoring and stable information transmission difficult. On the other hand, the deep and open sea area is far away from the land and belongs to a new remote fishery management mode. The production facilities can accommodate a limited number of operators, and it is difficult to continuously stationed, which requires higher management for personnel and equipment, and it is difficult to normalize real-time on-site management.
5. Insufficient breeding varieties with high added value
Due to the shortage of breeding varieties suitable for specific environmental conditions of deep and open sea aquaculture, more international varieties with high economic value and large demand are needed to promote the development of deep and open sea aquaculture industry, such as Atlantic salmon and tuna with high value.
At present, deep and open sea aquaculture in most countries in the world is still in the new and experimental stage of industrial development, and the entry threshold is high. It is mainly carried out by a few aquaculture companies with large deep-water cages and breeding vessels. The development of supporting industries of deep and open sea aquaculture is relatively insufficient, especially the stability and standardization of complete sets of equipment can not produce a strong industrial agglomeration effect, and it is difficult to form economies of scale in the short term. In recent years, China’s coastal provinces have increased investment and testing in deep and open sea aquaculture projects, driving the research and application of overall aquaculture equipment. It is believed that during the 14th Five Year Plan period, mature and reliable intensive aquaculture equipment will be introduced to the market for the benefit of the downstream aquaculture industry.