Pond cultivation technology of Scylla serrata

The scientific name of Scylla serrata is Scylla serrata, commonly known as worms and crickets. It belongs to the phylum Arthropoda, the class Crustacea, the order Decapoda, the suborder Reptiles, the brachycephala family, the family Portunidae, and the genus Scylla. It is one of the precious aquatic products in my country. Its meat is delicious and unique, and extremely nutritious. It is known as a delicacy at banquets and has high medicinal value. Especially female crabs with mature gonads after mating (red worms and tall crabs) are known as sea ginseng and are good for mothers and the elderly. An advanced tonic for young and infirm people, crab shells can be made into chitin, a widely used industrial raw material. Blue crabs are mainly distributed along the coasts of Guangdong, Guangxi, Fujian, Taiwan, Zhejiang and other provinces in my country, especially in Zhejiang, Fujian and Guangdong provinces. Abroad, it is mainly distributed in coastal waters such as Japan, Vietnam, Thailand, Philippines, New Zealand, the United States, the Indian Ocean, the Red Sea and South Africa.

Blue crabs like to inhabit and live in intertidal mudflats and muddy flats at the mouths of rivers, streams and seas, and in inner bays where seawater and freshwater buffer and exchange. Blue crabs are swimming, crawling, and burrowing crabs. They usually live in burrows during the day and come out of their burrows (caves) at night to look for food. Blue crabs are mainly carnivorous and like to eat small miscellaneous shells, small miscellaneous snails, small miscellaneous fish, small miscellaneous shrimps and small miscellaneous crabs. Blue crabs are also euryhaline marine crabs. The suitable salinity for their cultivation is 7‰~33‰, and the optimum is 10‰~20‰. The suitable temperature range is 6℃~35℃, and the optimum growth water temperature is 18℃~25℃. ℃, at this time the blue crab has strong activity, strong appetite, and its ability to withstand dryness is also extremely strong. After a healthy blue crab leaves the water, only a very small amount of water remains in the gill cavity to maintain the gill filaments. If kept moist, it can survive for several days. Blue crabs go through 13 molts in their life (including 6 larval metamorphosis molts, 6 growth molts, and 1 reproductive molt). In short, the metamorphosis and development of blue crabs and the entire growth and life process are always accompanied by It proceeds by shedding its shell. Generally, the 6th to 8th stage juvenile crabs that are stocked in spring (April to May) will reach a weight of 200g to 250g per crab after three and a half to four months of breeding in summer (July to August). , if the young crabs stocked in autumn (September to October) need to survive the winter and are cultured from May to June of the following year, they can also reach commercial specifications.

According to the production practice in coastal areas across the country for many years, the breeding production methods adopted have become increasingly diversified. There are crab ponds (ponds) for single culture, mixed pond culture, and low dam and high net culture on tidal flats. Setting up chuns and poles for hanging cages, cement ponds, etc. have all achieved varying degrees of good economic and social benefits. This article will describe the blue crab pond culture technology.

1. Construction of Crab Ponds

1. Selection of site for breeding mud crab ponds (ponds) should be built in a location with no industrial and agricultural production wastewater, no toxic substances, no pesticides and no domestic sewage. Pollution, fresh seawater, strong self-purification of water exchange, stable physical and chemical factors, large tidal range, calm inner bay, high tide area with a certain amount of land-source fresh water injected, seawater specific gravity between 1.007 and 1.021, pH value between 7.8 and 8.5, water temperature Within 10℃～30℃, the transparency is 20cm～30cm, the chemical oxygen consumption is 4mg/L～17.6mg/L, and the copper ion concentration does not exceed 0.488mg/L.

2. The soil quality of the crab pond tidal flat is not only related to the latent habitat of blue crabs, but also directly affects the firmness of the pond and dam, so it should be selected to retain water and not leak. , it is suitable to coat the ground with homogeneous soil that has high adhesion and is not easy to collapse.

3. Pond area: The ideal pond area for raising mud crabs alone is 3 to 5 acres, while the pond area for mixed shrimp and crab cultivation is between 10 and 20 acres. If the breeding pond is too large, it is required to use bamboo fences or barriers to separate it into several small areas to facilitate the cultivation of blue crabs of different sizes in different stages.

4. Pool shape and water depth The shape of a pool is generally rectangular or square (the aspect ratio of a rectangular pool is 5:3 ~ 3:2, and the water depth is 1 meter ~ 1.5 meters). The orientation of the pool is generally It is better to be long from east to west and short from north to south (but it is not mandatory). There are usually three types of pool bottom structures: flat bottom, slightly sloping bottom and pot-shaped bottom.