I. Three-dimensional utilization of water bodies
Water is a three-dimensional space, which is not only the habitat of animals (fish, shrimp, crab, etc.). ), which is also the place where plants (higher aquatic plants and phytoplankton) make nutrients. In the long-term evolution process, various aquatic organisms have formed their own ecological habits, including habitat water layer, nutrition mode, food structure and so on. According to this feature, people can arrange a variety of aquatic animals and plants in the same water body. In general, single stocking is a waste of space and food resources.
Second, the comprehensive utilization of matter and energy.
Ecological fish farming can make multiple use of biomass energy and turn waste into treasure. For example, the transformation of shallow aquaculture lotus, arrowhead, rice, fish, crab and shrimp combination; Crop straws or livestock manure are processed into feed for fish, and biogas leftovers can also be used as fertilizer for fish farming. In addition, food processing often produces a lot of leftovers, and a lot of organic nutrients remain in these wastes. This is not only a waste, but also a pollution to the surrounding environment. If a certain process is adopted to raise fish, sewage can be recycled and feed can be saved.
Third, rational allocation of biological structure.
When designing the biological structure of ecological fish farming, we should consider the mutually beneficial factors between organisms, make reasonable arrangements, and promote the advantages and eliminate the disadvantages. Multi-species polyculture is a scientific collocation of biological species with different ecological habits to make full use of water space and natural food resources. In the symbiotic system of rice, duckweed and fish, an efficient ecosystem of "cultivating duckweed to fix nitrogen, raising duckweed, removing cordyceps from fish and fertilizing rice with fish manure" has been formed. Connecting terrestrial system and aquatic system can also form a virtuous circle and promote the common improvement of ecological efficiency of the two systems. Such as mulberry fish ponds, and the recycling of materials among mulberry, silkworm and fish; Another example is the connection of grass, poultry, pigs and fish, which are interlocking and mutually utilized to form a high-yield and efficient ecosystem.
Fourth, the optimal combination of economic components.
Eco-fish farming is essentially an eco-economic system controlled by human beings, which combines the process of natural change with the process of socio-economic reproduction and becomes a process in which ecology and economy are intertwined. In this process, natural objects and economic objects, biological structure and economic structure are integrated, which requires people to strictly follow the ecological economic laws and optimize the ecological economic structure in the process of designing ecological fish farming system and implementing production.
In terms of scale production structure, ecological fish farming is a production mode of "fish-oriented and diversified management". Because of its multi-link transformation and multi-level utilization, it can obtain better economic benefits. Its advantages are high material conversion rate, high energy conversion rate, high capital profit rate and high land output rate.