1) How the fishing cages arranged
The arrangement of the fishing cages should be considered to ensure that each cage can carry out good water exchange, and the principle of management is convenient. The fishing cages should be arranged as sparsely as possible and staggered in the shape of the finished product.
2) The density of fishing cages
The density of fishing cages should be determined according to water quality conditions and management conditions. Fishing cages for cultivating silver carp and bighead carp can account for 1% of the large water surface in fatty waters with rich feed, and 0.5% of the water quality is thinner. Breeding edible fish depends on the water flow, water quality and fertility, and the level of dissolved oxygen in the water area itself. If the water flows well, the fertility is moderate, and the dissolved oxygen is high, then more cages can be set up, and vice versa.
3) Water layer set up in cages
The depth of the cage installation is generally not more than 3 meters. Due to the distribution of plankton, it accounts for 58.7% of the water layer within 2 meters, and 2-4.2 meters for 41.3%. Especially in the water with low transparency, phytoplankton is the most abundant. , And the number of zooplankton in the water depth of less than 1 meter of the water layer is less than the water layer of 1-2 meters, especially the highest density at 2-3 meters. Therefore, in waters rich in water quality and fertilizer and phytoplankton, the cages should be set up in a shallower water layer, but the bottom of the cages should be more than 0.5 meters from the bottom of the water. In waters with thinner water quality, or cages where bighead carp is mainly raised, it can be set in a deeper water layer as appropriate, but it should not be too deep.
4) Selection of fishing cage location
Fish culture in cages relies on the exchange of water bodies inside and outside the cage to maintain a good ecological environment in the cage. Therefore, the environmental conditions of the location where the cages are installed are critical to the success or failure of fish culture in the cages.
The place where the cage is set up should meet the following conditions: ①The water surface is wide, the water level is stable, the leeward wind is sunny, the water temperature is high, the water depth is 3-7 meters, the environment is quiet, the water quality is fresh, pollution-free, and the pH value is neutral and alkaline waters. ②Choose artesian water or tidal water. The water flow speed is generally 0.05-0.2 m/s to ensure the supply of oxygen. The rapid flow of water often causes the fish in the tank to swim with the top current, which consumes energy and affects growth; ③The cages that mainly raise silver carp and bighead carp should choose fertile water and rich plankton (generally the amount of phytoplankton per liter of water 2 million or more, containing more than 3,000 zooplankton is fat water), transparency of 30-50 cm, water containing less sediment and impurities. The turbid water quality is not conducive to the growth of plankton.