Cold water fish farming - how to build a cold water fish farm?
First, cold water fish breeding site selection Whether the proper selection of the breeding grounds will directly affect the production, production efficiency and economic benefits of the farm after the construction. That is to say before the construction site selection is essential, is related to the future success of the key to farming. In the construction site selection point need to consider the following basic conditions:
1. Raw water and water temperature of cold water fish farms
Cold water fish habitat in the water is clear, the end of the gravel, dissolved oxygen enough mountain streams. Adult growth limit temperature of 0 to 30 degrees, suitable for growth temperature of 12-20 degrees, the optimal growth temperature of 16-18 degrees. In the appropriate range of food intake, rapid growth, the body maintained a good metabolic state. Less than 8 degrees or higher than 20 degrees, loss of appetite, slow growth. More than 24 degrees, feeding stopped, the body failure and death. 27-30 degrees, short time. Therefore, the culture of cold water fish water needs clear water, no turbidity, no pollution, annual water temperature changes in the range of 5-20 degrees, the annual average temperature of 8-15 degrees, is the ideal water for farming. Usually water springs, mountain streams, groundwater, deep water reservoir bottom drainage and reservoir dam water can be used as aquaculture water.
2. Water and water in cold water fish farms
Cold water fish are sexual countercurrent and hi oxygen fish. Rich water and water are more important for cold water fish than other freshwater fish. Due to the stimulation of water, causing normal exercise, exercise to speed up the body's metabolism, thereby enhancing appetite, healthy. The water also serves to take the excreta away, and the most important role of the flow is to continuously supply fresh, oxygen-rich water to meet its oxygen demand. Therefore, the cultivation of cold water fish is different from other freshwater fish, the general use of water farming methods. The suitable flow rate for cold water fish is greater than 2 cm / s and less than 30 cm / sec. Usually in a certain water temperature, fish pond area, feeding density and breeding technology, the greater the water, the better the feeding effect. The size of the water directly determines the size of the annual production. When you build a site, you need to plan and design carefully according to the annual water quality.
3. Cold water fish farm dissolved oxygen
When the water dissolved oxygen below 3 mg / l, there will be a large number of deaths. The value is the summer death point. Less than 5 mg / l, the respiratory rate is accelerated, feeling unwell. To make good growth of cold water fish, dissolved in water is best to 6 mg / l or more, to 9 mg / l above the growth rate faster. If the water content of water injection is low, you need to take measures to improve the drop or oxygen or mechanical oxygen.
4. Cold water fish farm other conditions
Suitable for the construction of the conditions, should also consider the traffic, power and sales market and so on. In short, the site before the election point, to carefully survey the water temperature and water changes in the annual changes, with particular attention to observe the highest summer water temperature and winter minimum water temperature and maximum water and minimum water value. On this basis, through scientific demonstration, to carry out the overall planning and scientific survey and design, and then according to the funds and specific conditions, or once completed or staged to achieve.
Second, the construction of cold water fish farms - breeding ponds
(A) cold water fish farms - the type and size of the pond
Usually according to the purpose of use, can be divided into incubation ponds, juvenile ponds, adult ponds and broods. The ideal area and depth list are as follows. :
The actual depth of the pond is 20 to 30 cm above the surface. In the actual production, may be appropriate to use, that is, adult fish pool can be. Adult fish ponds can breed juveniles can also raise broodstock, without strict distinction.
(B) the shape and structure of cold water fish ponds
The shape of the cold water fish pond is round, oval, hexagonal, square, rectangular, waterway, irregular and so on. No matter what kind of shape of the pool, must be easy to exchange water, so that the flow of water in the pool, there is no dead ends, but also consider feeding and management and fishing and other convenient operation, making pool costs low. In short, should be in accordance with the site of the terrain, terrain, after in-depth study to be determined. At present, the majority of the rectangle. Usually the length of the juvenile pond is 5 to 6 times the width, and the length of the adult pond is 7 to 10 times the width. The width of the pond should not be too large, juvenile pond wide to 1.5 to 2 meters is more common, adult pond wide to 4 to 5 meters is more common.
Because it is water culture, fish pond water intake and the outlet of the gate to ensure the smooth flow of water under the premise to prevent the escape of fish. Therefore, the pond, the drain in addition to a gap, but also adjust the size of water. Where there is a gap between the water inlet and the water, two water injectors may be used. To pool width of 4 meters, for example, each water inlet width of 1.3 meters, two water points separated by 0.8 meters. Can also be used a width of 3 meters of water injection, so that the water dropped from a certain height into the pond. Do not have the gap when the nozzle should be filled as far as possible with the fish pond wide, in addition to the fixed gate of the column, so that the entire section to keep the water. In addition to preventing the fish from escaping to the water supply path, it is necessary to prevent the fish from entering the breeding pond. Drainage to set up two or three control gates, if the surface drainage, the first one for the escape gate, the second to control the water level of the gate. If the bottom of the drainage, the first for the escape gate, the second for the control of the bottom of the gate, the third to control the water level of the gate. The slope before and after the pool, adult fish pool to 0.8%, juvenile pond to 0.2% is appropriate.
(C) the identification of the area and number of breeding ponds
1. Calculation of the area of a fish pond: How much area a fish pond is to be built in a farm is usually calculated on the basis of the exchange rate of water and water. The exchange rate of water is the number of times the exchange of water per hour, namely:
Exchange rate = hourly water injection (cubic meters) ÷ pond total capacity (cubic meters)
For example: the total capacity of the pond is 100 tons, the hourly water injection is 100 tons, the exchange rate is 1; hourly water injection is 200 tons, the exchange rate is 2.
Construction of fish pond area of the formula is:
Fish pool area (square meters) = [hourly water injection (cubic meters) ÷ pond average water depth (m)] ÷ conversion rate
For example: the water injection per hour is 50 liters, the average depth of the pond is 0.6 meters, the exchange rate is set, then the appropriate pond construction area can be calculated as follows:
Fish pool area = [0.05 × 3600 ÷ 0.6] ÷ 1 = 180 ÷ 0.6 ÷ 1 = 300 (square meters)
2. Calculation of the number of fish ponds: According to the water injection to determine the fish pool area, the need for further scientific calculation and determine the number of fish ponds. Calculate the number of fish ponds to use the flow rate of water, usually cold water fish pond flow rate of 2 to 5 cm per second. According to the first type of fish pond width, and then according to the pond width to find a reasonable number of fish ponds.
The predetermined depth of water × the expected pool width × scheduled flow rate per second = water injection per second
Therefore, the expected pool width = water injection per second ÷ (predetermined water depth × scheduled per second flow rate).
For example: the water injection per hour is 100 liters, the water exchange rate is set to 1, the water depth of 0.6 meters, according to the formula to calculate the pool area, a reasonable build pool area of 600 square meters.
Scheduled flow rate of 4 cm per second, calculated as follows:
Scheduled pool width = 0.1 ÷ (0.6 × 0.04) = 4.17 (m)
The total pool area of 600 square meters, pool width of 4 meters, the length of 150 meters. You can build 4 meters wide, 37.5 meters long fish pond 4. If arranged in 2 rows, each row of 2 pools, the flow rate is 2 cm per second.