Lobsters breed once a year, with the peak period from May to September. The breeding of crayfish is quite special, and most of the breeding process is completed in caves, so it is difficult to see egg-holding shrimps in ordinary production. It takes 2 ~ 5 months for the ovary to finally mature after mating, and ovulation and fertilization are carried out. The fertilized egg is purple sauce color and adheres to the bristles of the swimming limbs in the abdomen. The egg-bearing shrimp often holds the abdomen close to the water in the hole to keep the egg in a moist state.
The brooding amount of lobsters is relatively small, generally ranging from100 to 700, with an average of 300 eggs. The incubation time of eggs is14 ~ 24 days. During the development of crayfish larvae, there is no need for any external nutrition supply, and the newly hatched larvae need to stay in the abdomen of the parent shrimp for about 10 days before they leave the mother. If the conditions are not suitable, you can survive in the cave for weeks without eating or drinking.
When the pond is filled with water, the larvae and parent shrimps climb out of the cave one after another and naturally distribute in the pond. Sometimes the parent shrimps bring their larvae into the water and then release them. Although lobsters hold fewer eggs, the survival rate of larvae hatching is very high. The scattered breeding habits of lobsters limit the large-scale production of larvae and bring adverse effects on intensive production.
Extended data:
Freshwater lobsters do not have strict requirements on pond conditions, so it is advisable to build ponds in places with sunny ventilation, soil to ensure water quality and pollution-free water sources. Generally, the pond size is 3333 ~ 6667 (5 ~10 mu), and the water depth reaches 1.5m or more. The bottom of sand and mud is flat, and the slope ratio of the dam is1:3 ~ 4. It has convenient water intake and drainage conditions and anti-theft protection measures. As a hidden habitat for lobsters, some aquatic plants can be planted in the pond or a certain number of stones, bricks, tiles and other shelters can be placed, accounting for about 1 13 of the total water surface.
Stocking of shrimp fry
Before stocking, clean and disinfect the pond with quicklime100 ~150kg/667m2 to kill the harmful fish and aquatic insects in the pond and avoid enemy invasion. After disinfection for 3 days, water is fed, and after 10, 300 ~ 500 kg/667 ㎡ of decomposed organic fertilizer is used to fertilize water, so as to cultivate rich plankton and provide sufficient bait for shrimp seedlings.
Generally, shrimp seedlings with a body length of 3 ~ 5cm, strong physique and no diseases are selected for release, and the stocking density can be controlled at 2,000 ~ 3,000, and the stocking density can be appropriately increased for shrimp seedlings with a size of 667㎡. Because the shrimp bullies the weak and fears the big, the specifications of the fry stocked in the same pond should be neat. Avoid excessive temperature difference between water and seedlings, and pool in the evening or at dawn. Before releasing the seedlings, slowly add a small amount of pond water into the seedling transport container until the water temperature of the container is close to that of the pond water, and then gently pour the shrimp seedlings into the pond water.
Pay attention to pest control in lobster culture;
1, black gill disease: After continuous rainy or violent rain, due to shallow and turbid pond water, water pollution, insufficient light and fungal infection, the gill of some diseased crayfish changed from red at first to brown until it turned black completely, and the diseased gill gradually lost its function of filtering water and supplying oxygen, and gradually the gill shrank. Prevention and control methods: every cubic meter of water body is sprayed with bleaching powder 1 g in the whole pool, or every cubic meter of water body is sprayed with 0.6 g of ozone compound preparation in the whole pool, and the medicine is applied twice a day. Sprinkle 5 grams of photosynthetic bacteria on every cubic meter of water after 3 days; Add 0.2% stable VC into the feed and feed it continuously for one week.
2, soft shell disease: the shell of the sick shrimp is soft, the two claws are not firm, the body color is dim, the action is slow, the appetite is poor, the growth is slow, and the ability to avoid harm is weak. The main reasons are long-term rain, lack of light in the pond, long-term acidity of PH value, too much sludge left at the bottom of some farmers' ponds, too high stocking density and uneven feed nutrients, which will all cause such diseases. Prevention and control methods: 20 grams of quicklime water per cubic meter of water is splashed in the whole pool, and the feed is balanced with meat and vegetable, and the feeding amount of green feed and bone meal is appropriately increased; Add 0. 1% VC, cod liver oil, glucose, Chinese herbal medicines and biological agents to the feed.
References:
Baidu encyclopedia: lobster