Foundational Studies On Artificial Breeding Of Scylla Paramamosian

Mud crab is one of the main Marine species widely distributed in coastal areas of China.Scylla paramamosian is called the "Hele Crab Scylla paramamosian",one of the four famous dishes in hainan.At present,most of cultured crab larval in pond is based on fishing in natural.With the expansion of the breeding scale,the number of wild seedlings is seriously insufficient,which brings great pressure to the natural resources of Scylla paramamosian.Artificial larval rearing technology is not stable and can not be produced in scale.It fundamentally restricts the development of the "Hele Crab Scylla paramamosian"breeding industry.This paper systematically studies the spawning,incubation and seedling cultivation of Scylla paramamosian which comes from wild and aquacultured.It aims at providing the theoretical basis and technical support for the breeding of the juveniles in factory.The main results of this paper are as follows:First,the effect of different salinity,exposure and desiccation,resection of the eye stalk and season on the spawning of wild and aquaculture crab.There are six groups of salinity,18,21,24,27,30 and 33 respectively.The dry stimulus was divided into three groups:no dry,dry 2h and natural dry.The resection of the eye stalk was divided into four groups:non-resection,right eye stalk,left eye stalk and both sides.The season is divided into first,second,third and fourth quarters.The number of spawning individuals was the largest both wild and cultured Mud crab When salinity was 30.it takes second place when salinity was 27.There are no one of wild species spawning when the salinityis between 18 and 24.A few cultured individuals spawning.The shortest test interval of spawning was 3.0d belong to cultured species in the salinity of 24.on the contrary,test interval is longest when the salinity is 18 was 13.0d.The number of spawning and attached egg was the largest in salinity of 27 of wild species,it respectively 1974581 and 1922262.The spawning rates of the cultured and wild species were 0.12 and 0.15 respectively.There was no significant effect on the number of spawning individuals with both bilateral and non-resected eye stalk,but the left or right single resected eye stalk had a certain effect on the number of spawning individuals.The number of spawning individuals of wild and cultured species in natural dry was greater than that of no dry and dry 2h.The spawning ratio of wild and aquaculture species increased successively in the three groups of no dry,dry 2h and natural dry.The second quarter(April to June)was the most fertile season for the breeding of Scylla paramamosian,followed by the third quarter.In the fourth quarter,the incubation rate was the lowest,the attached rate was 74.35%,and the abortion rate was up to 25.65%.Therefore,the suitable spawning salinity of Scylla paramamosian is between 27 and 30,which can be used to induction with resecting any unilateral eye stalk.Second,the incubation of mud crab with different temperature and salinity.Temperature is set to 24 ? 27 ? and 30 ?;The salinity is set in groups 24,27 and 30;Embryonic development is divided into 10 phases.Duration of embryonic development is significantly less than 24? and 27? compared to 30?(p<0.05).Embryonic development time is shortest under 30?,is 227.3±3.0 h.Diameter of oosperm is the largest under 30?,is 306.7±5.8um.The duration of embryo development in each stage in salinity of 24 was significantly greater than that of 27 and 30 patients,respectively.(p<0.05)The fertilized egg began to enter cleavage stage after7.0±1.0h under 30 ?.Compound eye pigment occurs in 123.0±2.5h,and 227.3±3.1h when the larvae hatched.The duration of embryonic development of the Scylla paramamosian under 30 salinity was significantly higher than that in 27 and 24 salinity(p<0.05).The development duration of the embryos under 24 salinity was the shortest,with a development length of 239.0±13.2h.With the increase of salinity,the duration of embryo development in each period gradually increased.Water temperature in 24? to 30?,under the condition of salinity in 27 to 30,longest embryonic development needs 279.0 h.Third,the effect of different parental seedlings and different breeding densities on the survival rate of the larvae and the molted separation.The density was divided into 100ind/L,150ind/L and 200ind/L respectively.The survival rate of progeny of wild crab during Z1-M was 8.43%,and the survival rate of progeny of cultured crab during Z1-M was 6.38%.The survival rate both of progeny of wild and cultured crab was the highest when the breeding density was 100ind/L,and the survival rate was 7.64%and 5.03%respectively.Molt interphase of the seedlings of the wild crabs in Z1-M increased gradually with the increase of the breeding density.And molt interphase were 19.7 days,22.0 days and 23.2 days respectively in the three densities.