In the past 20 years,pelagic aquaculture, especially deep pelagic aquaculture, has become a hot topic at home and abroad. China has a huge sea area for the development of deep-sea aquaculture and deep-sea aquaculture, and deep-sea aquaculture has caught the attention of the world with its rapid development. At the same time, the development of China’s pelagic aquaculture and deep pelagic aquaculture also faces many challenges and opportunities. This paper classifies and compares the types of marine aquaculture and the equipment of deep sea aquaculture, and summarizes the opportunities, challenges and development strategies faced by China’s offshore and offshore aquaculture, especially the development of deep sea aquaculture.
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Regional division of mariculture types
Due to the great differences in the environmental conditions of mariculture regions in various countries, there is no global consensus on the regional division of mariculture in the world. The United States defines aquaculture in the exclusive economic zone of 3 – 200 nautical miles offshore as offshore aquaculture. In the 2010 technical report of the Food and Agriculture Organization of the United Nations (FAO), marine aquaculture is divided into three categories: nearshore aquaculture, offshore aquaculture and offshore aquaculture according to the offshore distance, water depth and openness. The slope of the continental shelf in the Yellow Sea, Bohai Sea and the northern part of the East China Sea is gentle, and the scale of marine aquaculture is large. At present, the floating raft aquaculture in Shandong Province and Jiangsu Province of China has extended to the open sea area 15 km away from the coast. The official fishery statistics of China have defined the deep-water net cage as a net cage that has the ability of resisting wind and waves and is placed in the sea with a depth of 20 meters or more. Some well-known scholars have also defined pelagic aquaculture or deep pelagic aquaculture as mariculture in open waters with water depth greater than 20m. Based on the principles that are consistent with China’s national conditions, have certain inheritance and are conducive to management and development, this paper classifies China’s marine aquaculture into four categories: offshore aquaculture, offshore aquaculture, offshore aquaculture and deep-sea aquaculture, or equipment-based offshore aquaculture (Table 1).
Offshore and offshore aquaculture can also be combined as offshore aquaculture. Near-shore aquaculture includes mariculture in sheltered harbors or with visible near-shore sight distance (about 2km); Offshore aquaculture refers to marine aquaculture beyond the sight distance and with a certain sheltered water depth of more than 20m; The pelagic aquaculture is carried out in the open sea with a water depth of more than 20m; Deep sea aquaculture or equipment-based deep sea aquaculture is a sea aquaculture method that uses steel structure and equipment with automatic feeding system to resist or avoid strong typhoons. Some aquaculture activities are between the two types and can be classified according to their main characteristics.
Although the term “deep sea aquaculture” has appeared in China’s official documents and fishery academia, the marine science and geosciences do not recognize that its operating area belongs to the deep sea, and the public perception is also ambiguous. In addition, the vast majority of China’s current “deep sea aquaculture equipment” operate in the sea with a water depth of less than 50m. Therefore, it is more appropriate to express deeper offshore aquaculture in English than deep sea aquaculture. In the same way, it is more reasonable to adopt “equipment type offshore aquaculture” than “deep sea aquaculture”.