Breeding method of scylla paramamosain based on basket culture

Abstract

The application discloses a kind of based on basket culture Scylla paramamosain conservation method, belong to Scylla paramamosain conservation technical field, process includes: the crab seed juvenile crab 1 period mark coarse culture 1 month, select uniform female crab individual size to carry out basket culture, feed in basket living body shellfish, once a week feeds small miscellaneous fish, feeds again, breeds to before reproductive ecdysis;Female crab is mixed with mature male crab in the same pond before reproductive ecdysis, feeds fresh oyster meat, female to male ratio is 1:2, female and male mating again breed 10d, then female crab is hung up in cultivation basket, artificial induced spawning next year, induced spawning salinity 20%~25%.The conservation method of the application promotes mating female crab to develop into paste crab, and the short-term artificial induced spawning of paste crab can reach 25.6%~31.4%, which meets the general commercial seedling raising demand and breeding requirement, solves the problem of poor artificial conservation effect of mud crab breeding, and is suitable for different species source of mud crab original seed protection and commercial use.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of Scylla paramamosain conservation, and more particularly to a Scylla paramamosain conservation method based on basket culture. BACKGROUND

[0002] Scylla paramamosain, commonly known as mud crab, is an important marine crab breeding variety in China, which is distributed in the southeast coastal areas. With the continuous maturity of artificial breeding technology, the breeding industry has developed rapidly.

[0003] Due to the over-reliance on wild crab for artificial breeding, production is limited. The source of artificially bred mud crabs is complex, the salinity environment is complex, the pond breeding disease is more common, and the mating opportunity is difficult to direct control. Therefore, the quality of the bred crab is poor. Although partial salt reduction breeding methods can achieve mud crab conservation, the success rate of induced production is still low, even less than 5%, and it is more difficult to achieve large-scale continuous dynamic conservation. As a result, the progress of the seed industry is slow, so effective mud crab conservation is the basis for the development of its germplasm resources and is of great significance to the development of the industry.

[0004] Therefore, how to provide an effective mud crab conservation method is a problem that those skilled in the art need to solve. SUMMARY

[0005] Therefore, the present application provides a Scylla paramamosain conservation method based on basket culture.

[0006] In order to achieve the above purpose, the present application adopts the following technical solutions:

[0007] A Scylla paramamosain conservation method based on basket culture includes the following processes:

[0008] (1) Female crab stage culture: cultivate 1-month-old crab larvae 1st instar, select female crabs with uniform size for basket culture, feed live shellfish in the basket, feed small miscellaneous fish once a week, and feed again after eating, and culture until before reproductive ecdysis;

[0009] (2) Mating: mix female crabs with mature male crabs in the same pond before reproductive ecdysis, feed fresh oyster meat, the female to male ratio is 1:2, and after mating, the female crabs are cultured in the basket for 10 days, and then the female crabs are cultured in the basket for 10 days, and then the female crabs are cultured in the basket for 10 days.

[0010] Preferably, the basket culture is carried out on the near-river estuary floating raft oyster culture rack, and the regional seawater salinity is 5% to 15%.

[0011] Salinity is a necessary condition for cultivating mud crabs. Too high or too low salinity affects the development of gonads. If the salinity exceeds the suitable salinity, the conservation object will develop degenerative or stagnant body development in the later stage.

[0012] Preferably, the hanging basket refers to a perforated basket that does not restrict the movement of adult crabs, prevents escape, and allows more than 50% light to pass through the top.

[0013] Preferably, in step 1), the live shellfish are shellfish adapted to certain salinity changes, including: oysters, estuarine clams, or Manila clams.

[0014] Preferably, in step 1), the reproductive molting refers to the 13th molting.

[0015] Preferably, in step 2), the basket refers to a perforated basket that does not restrict the movement of adult crabs, prevents them from escaping, and allows more than 50% light to pass through the top, with an opening of 0.05m × 0.05m at the center of the top of the basket.

[0016] Preferably, in step 2), the specific process of suspending the culture basket includes: the culture basket is 1.5-2 meters above the water surface, made of plastic, with a light transmittance of 50% at the top and a water transmittance of 20% at the sides and bottom. Four crab houses are built inside the basket by binding bricks to the bottom. Each crab house is built by four bricks, with the bottom two bricks standing 10cm apart and 5cm high. The top is covered with two bricks. Each brick is fixed to the hollow basket body with straps. The crab houses are built at the four corners of the basket, which also increases the total weight of the basket. The upper part of the culture basket is suspended from the oyster float valve extension rope with a hemp rope.

[0017] As can be seen from the above technical solution, the technical effects achieved by this invention are as follows: This invention is based on basket-based aquaculture for the preservation of mud crabs, focusing on the basket-based simulated ecological aquaculture of mud crabs. The natural changes in salinity environment of the floating raft oyster culture are extremely consistent with the development and preservation requirements of mud crabs. Therefore, this invention provides a comfortable development environment and uses live shellfish as a feeding guarantee, ensuring that there are basically no diseased or dead individuals and that nutrition is balanced during the aquaculture process. Moreover, basket-based aquaculture allows for convenient observation and accurate control of the mating time of female crabs, preventing the phenomenon of 12 molts and mating. By controlling the female-to-male ratio at 1:2, the abundance of male parents from different sources, unlike the traditional mixed culture of male and female parents from the same batch, ensures the success rate of mating and fertility, and promotes that all mating female crabs can develop into roe crabs. The short-term artificial spawning and egg-carrying rate of roe crabs can reach 25.6% to 31.4%, meeting the general commercial seedling and breeding requirements, solving the problem of poor artificial preservation effect of mud crab breeding, and is suitable for the protection and commercial use of mud crab original species from different sources. Detailed Implementation

[0018] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] Example 1

[0020] A method for breeding Scylla paramamosain based on hanging basket culture, the process is:

[0021] (1) In May, the female crab seed source is from the western coast of the Beibu Gulf, artificially bred to 1st instar crab, then cultured in a pond with sandy bottom, fed with prawn compound feed and boiled water surimi, the total weight of the crabs is estimated at 30%-100% (the feeding amount of the green crab is directly related to the change of climate and environment, and it is not the daily feeding amount, here the feeding is moderately added according to the feeding situation of the green crab, and there is no fixed value, the molting period or weather change may not feed for one or two days, and the feeding rate may reach 100% when the weather recovers or the thick shell becomes hard after metamorphosis), cultured for one month, observe the growth and molting, and record the molting times. Then select female crabs of the same size to culture in baskets. In June, the crabs in the baskets are hung and cultured under the oyster strings of oyster rafts in the estuary sea area, the salinity is 5%-15%, the culture baskets are 1.5-2 meters away from the water surface, plastic baskets are used, the top of the basket has a light transmittance of 50%, the side and bottom of the basket have a water permeability of 20%, the bottom of the basket is bound with bricks to set up four crab houses, each crab house is built by four bricks, the lower two bricks are vertical with a distance of 10 cm and a height of 5 cm, the top is covered with two bricks, each brick is fixed on the hollow basket body with a binding belt, the crab houses are set up at the four corners of the basket, and the total weight of the basket body is increased, the upper part of the culture basket is hung on the oyster float valve extension rope with a brown rope, live small miscellaneous oysters, philippine clams and estuary clams are fed, and the feeding is repeated within 3 days, the residual shells are not cleaned, which is beneficial for the crabs to hide, and miscellaneous fish is fed once a week, the feeding amount is 50% of the weight of the crabs in the basket, and the molting times are recorded according to the observation of the molted crab shells;

[0022] (2) The female crabs that have molted 12 times and have been in the water for 20 days are put into the pond and cultured with male crabs, the female to male ratio is 1:2, the male crabs are 1-year-old crabs, and bricks are put in for shelter, fresh oyster meat is fed, and the mating situation is observed, the mated crabs are taken out and cultured for 10 days, and then hung and cultured in the sea area according to the original hanging method, the next year in April, the seed crabs are taken back to induce spawning, the salinity range is 20%-25%;

[0023] This time, 223 mated female crabs were used, 57 crabs were induced to spawn, the induction period was 30 days, and the spawning rate was 25.6%.

[0024] Example 2

[0025] A method for breeding Scylla paramamosain based on hanging basket culture, the process is:

[0026] (1) In June, the female crab seed source is from the western coast of the Beibu Gulf, artificially bred to 1st instar crab, then cultured in a pond with sandy bottom, fed with prawn compound feed and boiled water surimi, the total weight of the crabs is estimated at 30%-100% (the feeding amount of the green crab is directly related to the change of climate and environment, and it is not the daily feeding amount, here the feeding is moderately added according to the feeding situation of the green crab, and there is no fixed value, the molting period or weather change may not feed for one or two days, and the feeding rate may reach 100% when the weather recovers or the thick shell becomes hard after metamorphosis), cultured for one month, observe the growth and molting, and record the molting times. Then select female crabs of the same size to culture in baskets. In June, the crabs in the baskets are hung and cultured under the oyster strings of oyster rafts in the estuary sea area, the salinity is 5%-15%, the culture baskets are 1.5-2 meters away from the water surface, plastic baskets are used, the top of the basket has a light transmittance of 50%, the side and bottom of the basket have a water permeability of 20%, the bottom of the basket is bound with bricks to set up four crab houses, each crab house is built by four bricks, the lower two bricks are vertical with a distance of 10 cm and a height of 5 cm, the top is covered with two bricks, each brick is fixed on the hollow basket body with a binding belt, the crab houses are set up at the four corners of the basket, and the total weight of the basket body is increased, the upper part of the culture basket is hung on the oyster float valve extension rope with a brown rope, live small miscellaneous oysters, philippine clams and estuary clams are fed, and the feeding is repeated within 3 days, the residual shells are not cleaned, which is beneficial for the crabs to hide, and miscellaneous fish is fed once a week, the feeding amount is 50% of the weight of the crabs in the basket, and the molting times are recorded according to the observation of the molted crab shells;

[0027] (2) The specific operation is the same as in Example 1, except that the male crabs are wild near 1-year-old crabs. The wild crabs can avoid the possibility of inbreeding. In addition, the wild crabs in the sea area are preferably large in size, have good shell shape, strong claws, and strong resistance. Moreover, because the feeding of the wild crabs is not single, the quality of their sperm is better than that of the cultured crabs. Dissection shows that the gonad development is good.

[0028] This time, 213 mating female mud crabs were used, and 68 induced ovulation crabs were used. The induced ovulation period was 30 days, and the egg-carrying rate was 31.4%.

[0029] Each of the embodiments in the specification is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other.

[0030] The above description of the disclosed embodiments enables a person skilled in the art to implement or use the present application. Various modifications to the embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for breeding Scylla paramamosain based on basket culture, characterized in that, The process comprises the following steps: (1) female crab stage culture: the crab larvae juvenile crabs of stage 1 are cultured for one month, and female crabs with uniform size are selected for basket culture, live shellfish are fed in the basket, small miscellaneous fish are fed once a week, and feeding is repeated until the reproductive ecdysis; (2) mating: before the reproductive ecdysis, the female crabs are mixed with mature male crabs in the same pond, and fresh oyster meat is fed, the female to male ratio is 1:2, after mating, the female crabs are cultured for another 10 days, and then the female crabs are hung in the culture basket, and the next year, artificial induction is performed, the salinity is 20‰-25‰; The basket culture is carried out on the near estuary floating raft oyster culture rack, the basket is 1.5-2 meters away from the water surface, and 0.2-0.4 meters away from the ground of the culture sea area, and the regional seawater salinity is 5‰-15‰; In step 1), the live shellfish is a shellfish suitable for certain salinity changes, including oysters, near estuary clams or philippine clams; In step 2), the specific process of hanging in the culture basket includes that the culture basket is 1.5-2 meters away from the water surface, and 0.2-0.4 meters away from the ground of the culture sea area, a plastic basket is used, the light transmittance of the top of the basket is 50%, and the water permeability of the side and bottom of the basket is 20%.

2. The method according to claim 1, wherein the culture is carried out in a hanging basket. The basket refers to a perforated basket without limiting the movement of adult blue crabs, preventing escape, and the top transmittance is more than 50%.

3. The method according to claim 1, wherein the culture basket is a net cage. In step 1), the reproductive ecdysis refers to the 13th ecdysis.