Artificial breeding technology of Jiangfeng No. 1, a new variety of spotted forktail catfish
Text/Mei Dongsheng
1. Broodstock breeding
1. Broodstock should be over 4 years old, weigh more than 1.5 kg, and have a body length of 30 to 50 cm. The ratio of males to females is 1:1.1.
2. Broodstock breeding pond Broodstock breeding pond 5~10 acres, water depth 1.5~2 meters. The bottom of the pool is hard and flat, suitable for placing ovary laying, easy egg retrieval, and inlet and drainage facilities are well functioned. [Yoshiyama Huayao self-media network debut]
Second, broodstock stocking
1. The selected broodstock are stocked at a density of 200 kg/mu according to the size of the pond, and 200 to 300 silver carp species are used to adjust the water quality. Be careful not to put carp and crucian carp species.
2. Feed the compound feed with a protein content of more than 35%, and the feeding amount should be about 15 minutes to eat. Before spawning and one month after spawning, some animal feeds, such as small trash fish, are appropriately fed. And it is necessary to open the pump to flush the water frequently.
3. Spawning and fertilization
1. Ovarian setting The ovary of the fine seed farm uses a custom cylinder, the diameter of the cylinder mouth is 0.2 meters, the height of the cylinder body is 0.6 meters, there is a small hole at the bottom, and the cylinder mouth has a hole to facilitate the insertion of the buoy through the rope. It can also be made of plastic, wood, etc., and is suitable for the size to accommodate 1 pair of broodstock. An opening at one end of the ovary allows broodstock to move in and out freely. The number of ovary laying generally accounts for 20% to 30% of the broodstock pair. When the water temperature reaches above 19 °C, the placement of ovary is begun, and the ovary is generally placed flat at the bottom of the pool 3 to 5 meters from the shore, with the opening end facing the center of the pool, with a spacing of 5 to 6 meters. To make it easier to identify when collecting egg blocks, each ovarian opening end is tied with a rope, and one end of the rope is tied with a buoy. When the water temperature rises above 20 ° C, the ovaries should be checked regularly.
2. Egg mass collection Spotted forktails are often laid in the nest in the evening or early morning, and the eggs are completed at 8-9 a.m. Egg mass collection should be done before 12 a.m. Before collecting the egg blocks, gently raise the upper end of the ovary to the surface of the water, if there are broodstock in the nest, carefully drive the fish out, and then check for egg masses. If there are egg pieces, they are gently removed by hand, placed in a pre-filled bucket and sent to the incubation workshop in time for artificial incubation; if there are no egg blocks, the ovary can be slightly moved to the position, which helps to stimulate broodstock spawning.
4. Artificial incubation
1. Incubation conditions Incubation water requires fresh water quality, pollution-free water, water temperature is 20 ~ 30 °C, the most suitable 23 ~ 25 °C, the amount of dissolved oxygen in the water body is maintained at more than 5 mg / l, pH 6.5 ~ 8.0.
2. Artificial incubation method The collected egg pieces are soaked and sterilized by soaking in potassium permanganate solution at a concentration of 3 mg/L for 10 to 15 seconds, placed in the incubation box with a frame eye of 0.5 to 1 cm, and hung in the incubation tank, the tank size is 2.1 m×0.7 m×0.4 m, and the overflow is 0.3 m from the bottom of the slot. An incubation tank can hang 8 to 10 incubation boxes, an incubation box can put two egg blocks, and too large eggs need to be divided into small pieces to avoid the death of hypoxia in the middle fertilized eggs. Hatching sink at one end of the water, the other end of the water, the outlet height control of the sink water level, the need to use a mesh cover at the outlet to prevent the hatched fry from flowing away with the water, the hatching tank flow can not be less than 15 liters / min. There is a rotating shaft above the sink, there is an S-shaped paddle board on the shaft, the length of the paddle board is suitable for the shaft to go deep into the groove 50% to 70% when rotating, the incubation frame is placed on both sides of the S-shaped paddle board and fixed, and the rotation frequency of the motor connected to the rotating shaft is 30 rpm / minute. During incubation, the egg mass can be turned appropriately and care should be taken to remove the dead eggs. After about 1 week of incubation, the hatched yolk seedlings will naturally settle at the bottom of the hatching tank and form clumps. With the most of the four corners in the tank, the fry can be sucked out of the pond by siphoning.
5. Fry rearing
1. Domestication of yolk fry From the hatching tank, the yolk fry are quickly placed in the fry domestication pond with a size of 3.1 m× 2.1 m × 0.6 m. The domestication pond is set up for flowing water, and a mesh cover needs to be provided at the outlet, and the overflow port is 0.4 meters away from the bottom of the pool. Spray facilities are added above the domestication pool to increase the amount of dissolved oxygen in the pool, and facilities such as aerobic pumps can also be placed in the pool to prevent hypoxia. After 1 to 2 days of domestication, the yolk of the fry disappears and floats to the surface, at which time it can be stocked. In case of special circumstances, if it cannot be stocked in time, the powder can be fed in the proportion of fry in the domestication pond, but it cannot be delayed for too long, otherwise the mortality rate of fry will be increased. Stocking without domestication also increases fry mortality.
2. Fry stocking Prepare the fish fingerling pond, clear the pond in advance for disinfection, the pond is about 3 acres, and the water depth is 1.5 to 2 meters. Stocking density of 4000~7000 fish/mu. After the fish are planted in the pond, 300 to 500 silver carp summer flowers are matched per acre. Mainly artificial feeding, feed protein content of about 35%. According to the water temperature feeding, when the water temperature is 15 to 32 ° C, it is fed twice a day, once in the morning and once in the evening; the water temperature drops below 15 ° C, and it is fed once a day until the feeding is stopped.
6. Precautions
The entire breeding process needs to be managed, especially the artificial incubation link needs to be supervised 24 hours a day to prevent water shortage, power outage, lack of oxygen and other accidents. Problems found should be dealt with immediately and without delay. The custodians shall not be less than two persons, and after professional training and practical training, they shall be able to deal with special situations in an emergency manner. Pay attention to personal safety during operation. The entire breeding process consists of waterways, circuits and mechanical rotations.