The influence of water quality on lobster production can not be ignored. The quality of water directly affects the healthy growth and development of lobsters. In the process of culture, the pH value of pond water is kept between 7.5 and 8.5, and the transparency is between 30 cm and 40 cm. It is necessary to add fresh water frequently, sprinkle quicklime solution regularly, adjust the water quality, and prevent diseases and incomplete shelling.
The second is to feed the feed reasonably. Lobsters will kill each other when they are hungry and lack of food, so the feeding amount must be sufficient. Lobster feed is animal and plant feed. Plant feed is wheat, aquatic plants, rapeseed cakes, etc., and animal feed is miscellaneous fish, miscellaneous meat and internal organs. Usually, the feeding time, feeding amount and feeding method are determined according to the habit of lobster lying in the daytime and coming out at night and the density of shrimp in the pond. Otherwise, it will increase the cost of feed and reduce the benefit of breeding.
The third is scientific fishing. In the process of lobster culture, young shrimps can grow to commercial specifications in 60 ~ 90 days under the condition of suitable temperature and sufficient feed. Seedlings will be released in March, and rotation fishing will start around June, and the big ones will be caught and the small ones will be kept. Due to the large catch and the small catch, the catch rate can be improved and the price can be sold at a good price, so as to achieve the goal of high yield and high efficiency.
Seedling breeding
1, parent shrimp selection
Parent shrimps can be selected in September 9- 10/October of last year or March-April of that year, with a required weight of 30-50g, complete appendages, health and disease-free, and strong mobility, with a male-female ratio of 2-3:1. Male and female lobsters have obvious characteristics in appearance and are easy to distinguish.
① The males of sexually mature lobsters are significantly larger than females;
② The male dragon's foot is thick, and there is a bright red soft wart on the outside of both ends of the dragon's foot, while the female dragon's foot is relatively small, and most of the female feet have no red soft wart, even if there is color, it is pale;
(3) The male genital hole is opened at the base of the fifth pair of feet, while the female genital hole is opened at the base of the third pair of feet;
④ The abdomen of sexually mature female shrimp is enlarged, while that of male shrimp is relatively narrow.
2. Parent shrimp cultivation
The suitable area of parent shrimp pond is about 1200m2, and loam is the best substrate. The water depth is about 1m, and the width of the pond ridge is more than1.5m. There are sufficient and good water sources, and the water injection and drainage outlets are built. The surrounding ponds are built with plastic films or calcium-plastic plates to prevent them from escaping from the wall. Before stocking, 7. After disinfection, filter (to prevent wild fish from entering the pool), inject water to a depth of about 1m, and apply 500-800 kg/mu of decomposed livestock manure to improve the water quality. Hidden objects such as branches, roots, bamboo tubes, etc. for shrimp to climb and inhabit are put in the pond, and some aquatic plants are transplanted.
Parent shrimps can be put into the parent shrimp pond for 40-60 kg/mu, and soaked in 3% salt for 0/0 minute before stocking to kill pathogens. In order to make full use of the water body and adjust the water quality, 50- 100 silver carp and bighead carp can be mixed at the same time. During the cultivation period, fresh aquatic plants, bean cakes, wheat bran or compound feed can be fed, and a part of animal feed can be added. Such as chopped snail meat, livestock and poultry slaughter leftovers, etc. Daily feeding amount: 2%-3% of the parent shrimp's weight in March, 4%-5% in April, 6%-8% after May, and feeding 1 time every morning and evening, mainly in the evening, accounting for 70% of the daily bait amount. At the same time, strengthen water quality management, and change new water every 10- 15 days/time, and change water every time 1/3; Sprinkle quicklime 1 0-25g/m2 with water1time every 20 days to maintain good water quality and promote gonad development of parent shrimp.
3, parent shrimp breeding
From April to May, when the water temperature is above 20, the parent shrimps begin to mate. The fertilized egg hatches in the belly of female shrimp to become juvenile shrimp, and the incubation time takes 40-70 days. After hatching, the growth and development process of juvenile shrimp is completed under the protection of the mother. As soon as the young shrimp leave the mother's body, they can take the initiative to feed and live independently. When a large number of young shrimps are found in the breeding pond, they should be collected in time for shrimp seedling cultivation.
4. Parent shrimps overwinter
The lowest survival water temperature of lobster is 5℃. However, when the water temperature is lower than 9℃, the mortality rate of shrimps about 3 cm is very high during overwintering. Although adult shrimps can survive, a large number of deaths will occur after 2-3 months. Therefore, it is also an important link in the whole breeding work to do a good job of overwintering parent shrimp and ensure that the water temperature during overwintering is 16℃-18℃.
The overwintering method of parent shrimps is the same as that of Macrobrachium rosenbergii. The common overwintering methods include plastic film covering pool insulation method, electric heater heating method, hot spring water overwintering method, factory surplus hot water overwintering method and glass room overwintering method, all of which can achieve the effect of safe overwintering of parent shrimps.
5. Seedling raising technology
Although the amount of eggs held by lobsters is small, the fertilization rate can be above 98% and the hatching rate can reach 80%-85%. The problem is that the larvae grow and molt frequently after emergence, which is easily restricted by environmental conditions and affects the seedling raising rate. To improve the seedling raising rate, the key points are as follows:
① Water quality requirements
During lobster breeding, it is necessary to keep the water body relatively stable, the water quality fresh, and the pH value between 6.5 and 8; Prevent the temperature difference between day and night from being too large; Dissolved oxygen in water should be kept above 5.6 mg/L.
② Water environment
There must be water hyacinth (accounting for1/3) on the surface of the water, and it is best to have aquatic plants and hidden caves at the bottom of the water, so as to increase the attachment of shrimp larvae to shed their shells, which is also convenient for grasping the emergence time and shrimp growth through the inspection of water hyacinth seedlings. Fences and filter nets are added at the water inlet to prevent harmful organisms from entering the pool, frogs from laying eggs and tadpoles from eating shrimp seedlings. At the same time, it is necessary to prevent the parent shrimp from climbing and escaping.
③ Strengthen inspection.
Insist on checking the emergence situation in the morning and evening. When the young shrimps are free from the mother, catch the parent shrimps in time and return them to the parent shrimp pond for re-cultivation. Try to reduce the number of fish in the pond, and be especially careful in operation to avoid affecting the parent shrimps holding eggs and the newly hatched young shrimps.
④ Ensure feeding.
Small zooplankton, such as rotifers, will be cultivated in time for the newly hatched shrimp. It is estimated that a small number of small zooplankton will be fished from the special feed pond to the shrimp nursery pond 3-5 days before emergence. And use cooked egg yolk, soybean milk, etc. to supplement the food supply needed by larvae and young shrimps in time.