CN1545866A - Breeding and growth methods of Chlamys scallop seedlings in autumn - Google Patents

Abstract

The invention relates to the method for Pinna pectinate autumn offspring breeding and pruning, which comprises, selecting August to September for offspring breeding, choosing the eligible parent shellfish, after 10-15 days, regulating the parent shellfish sex gland to synchronous ripening, carrying out oviposition and fertilization, and carrying out scallop larva incubation, after 13-18 days, adhering the larva to juvenile mollusk through metamorphosis, cultivating the juvenile mollusk temporarily for 10-15 days, then carrying out seedlings protectoin on the sea, breeding on the sea in November, and harvesting during September to November in the next year till the July of the third year.

Description

Breeding and growth methods of Chlamys scallop seedlings in autumn

technical field

The invention relates to an aquaculture technology, in particular to a method for breeding and growing scallops in autumn.

Background technique

At present, the artificially cultivated Chlamys farreri is seeded in spring (March-May). Generally, sea scallops are temporarily raised and seedlings are kept in May-October, and seedlings are grown in October-November or March of the next year. Under normal circumstances, it will be harvested after October of the second year. Since 1996, due to large-scale diseases, most of them were harvested before August. This spring breeding mode of Chlamys farreri has many disadvantages. In the Yellow and Bohai Sea regions, the water temperature is very low from March to May, and the seedlings need to be heated by boilers to ensure the temperature of the seedling water body, so a lot of energy is consumed and the cost is increased; especially for scallops. The seedlings enter the high temperature period soon after entering the sea, which is not conducive to the growth of scallops, and the individual size of the seedlings is small. In particular, the unsuitable cultivation environment promotes early gonad development of Chlamys farreri. It takes 2-3 instars to develop gonads in normal natural environment, but the gonads can mature at the first instar under breeding conditions, and the minimum biotype is reduced from 3 cm or more to about 1.5 cm. , gonad development not only affects the growth of scallops, but also because the breeding season coincides with the high temperature period, the oviposition shells are weak and the high temperature environment causes the growth environment of scallops to deteriorate, such as red tide and a large number of microbial growth, and the growth of attached organisms in shell cages is fast , reduce the water exchange efficiency of the culture cage, etc., often induce large-scale diseases. In recent years, spring seedling scallops often die on a large scale, which is not unrelated to the spring seedling culture mode. For example, in 1998, the dead area of scallops in Shandong Province reached 167,000 mu, with a mortality rate of over 70%, and some even failed to harvest. A large area of scallops has also died in the sea area of Liaoning Province. In addition, the study found that the mortality rate of scallops increased after releasing sperm eggs, which is not only related to physical weakness, but also may die in large numbers after completing their life cycle, just like other aquatic organisms. In order to avoid losses, farmers often harvest suddenly before the high temperature period in August and September, resulting in a large amount of supply to the market in a short period of time and affecting economic benefits.

Contents of the invention

The object of the present invention is to make scallops grow seedlings and grow in autumn through artificial control, that is, to provide a mode of breeding and growing scallop seedlings in autumn. To start seed breeding, first select qualified parent shellfish, regulate the synchronous maturation of the parent shell gonads for 10-15 days, and then carry out oviposition and fertilization, and then carry out scallop larvae cultivation. After indoor temporary breeding for 10-15 days, the sea seedlings are preserved, and the sea culture is carried out in separate cages in November. After passing the first high temperature period, the breeding starts to harvest from September to November of the second year until the seawater high temperature period of the third year ( about July) can be harvested.

This breeding and growing mode has many advantages, because the seedlings are raised in August-September, and the water temperature and temperature are suitable for the cultivation of Chlamys farreri larvae, so no or little temperature adjustment is needed, which saves energy consumption and seedling raising costs. The time for autumn seedlings to enter the scallop growing cages is after October, so that the scallops can experience two consecutive suitable growth seasons and a high temperature period during cultivation, avoiding the high temperature period soon after the conventional spring seedlings are divided. Due to the unfavorable environment of large-scale reproduction of attached organisms and large-scale proliferation of microorganisms in the environment, it is necessary to experience two high-temperature periods and only one continuous suitable growth period to grow large-scale shellfish. In autumn and winter, the attached biomass of aquaculture equipment is reduced, which can ensure normal water exchange. In the second summer, when spring seedlings scallops overlap with the breeding season and high temperature period, they usually die on a large scale. Due to their young age, scallops have not yet entered the stage of gonad development, and their body constitution is good, so they can successfully pass through the high temperature period and the period of high incidence of diseases, so as to prevent the mass death of Chlamys farreri and enter the second continuous suitable growth period. It provides conditions for developing large-scale commodities. The culture time of autumn scallops of the same size is 3-6 months shorter than that of spring seedlings, and the yield is higher than that of spring seedlings. At the same time, the possible diseases and other risks are greatly reduced due to the reduced culture time. And the harvest period does not need to be concentrated in August and September, but the extension of the harvest period is greatly beneficial to market sales, which can maintain a higher market price and improve the economic benefits of cultivation.

Detailed ways

Concrete method and steps of the present invention:

1) Time selection for breeding of Chlamys farreri seed and preparation for raising seedlings in autumn

Usually choose to start seed breeding of Chlamys farreri from mid-August to September in autumn, and make preparations for breeding in advance, such as preparation and cleaning of seedling breeding equipment, disinfection, division of labor, and propagation of algae species.

2) Screening and temporary raising of broodstock for the breeding of Chlamys farreri seedlings is to select healthy broodstocks with well-developed gonads in mid-to-late August, clean them, and select male and female separately into the pond for temporary breeding. The stocking density should be controlled below 30-50 per cubic water body. It can be suspended in cages or floating rafts for temporary storage. Aerated properly, running water or changing the water 1-2 times a day, and feeding flat algae, For golden algae or other particulate artificial baits, it is necessary to frequently remove the excrement of parent shellfish and remove dead and diseased shellfish during the cultivation period. Use an air conditioner and a refrigerator to control the water temperature. Generally, under the condition of the water temperature of 17.5-21°C, after 10-15 days of feeding, the gonad development of the brood is basically synchronized. In order to increase the gonad development synchrony of the brood, you can Temporarily raised at 19-20°C;

3) The induced labor and fertilization of brood shells are to select male and female brood shells with well-developed gonads respectively, and dry them in the shade for about 30 minutes. The female shells are placed in the spawning pond to induce spawning, and the water temperature is 22-23°C; It can only be placed in a bucket or a small sink to drain semen, with a proper amount of air, and the water temperature is about 20°C. After the peak period of sperm and egg discharge, insemination can be carried out, and the number of sperm should be controlled at 5-7 sperm attached to each egg.

4) The standards for scallop embryo hatching, selection, and larvae cultivation are basically the same as those of spring seedlings. The density of scallop larvae is more than 8/ml, and the water temperature can be kept at 17-21°C or natural water temperature. After 12-15 days of cultivation , when the ratio of eye-spot larvae reaches more than 70%, generally at this time the larval shell length is about 180-200 microns, and the attachment base can be put in. After the metamorphosis is attached, it is managed as usual.

5) The growth of autumn seedlings of Chlamys farreri refers to the juvenile shellfish bred from autumn seedlings of Chlamys farreri. After the juveniles are temporarily raised at sea, the seedlings can be raised in mid-November. At this time, the shell height of juveniles is generally around 0.5-1.5 cm. Each cage is filled with 35-45 seedlings per layer, which is determined according to the culture conditions and technology. Other daily management is the same as that of scallop culture in spring.

6) Harvesting is generally available from September of the second year to July of the third year. The harvesting period is longer. The harvesting time is determined according to the size of the scallops and market demand. The size of the scallops can reach 5-9cm when harvested.

The present invention is due to carrying out the breeding of Chlamys farreri seedlings in autumn (August-November every year), and the seedlings are divided into cultivation after autumn, so as to avoid the need to go through two summer high-temperature discomfort periods in the current spring seedling cultivation of Chlamys farreri, especially the second A problem of large-scale death of scallops in high temperature period, and shorten the breeding cycle. Autumn seedling breeding technology includes autumn temporary rearing of Chlamys farreri broodstock and gonad development regulation technology before autumn seedling breeding, autumn seedling larvae cultivation technology, and autumn seedling spat temporary rearing and cultivation technology. Compared with the current spring seedling breeding method, the present invention has short cultivation time, uses the first suitable growth stage (the autumn of the current year and the spring of the second year) to promote the rapid growth of young shellfish, and avoids the spring seedlings from growing scallops in the spring of the second year. Premature gonad development affects the growth of young scallops, and the physique is weak after spawning, and the unfavorable factors that are prone to mass mortality due to the coincidence of the breeding period and the high temperature period make the scallops grow safely through the summer. At the same time, the second suitable growth stage (autumn of the second year and subsequent winter and spring) is used to grow large-scale commercial shellfish, which can change the problem that the current harvest period is concentrated before the high temperature period, prolong the harvest season, and improve economic benefits.

Claims (2)

1, chlamys farreri seed breeding in autumn and form method, it is characterized in that being chosen in and the 8-9 month begin the chlamys farreri seed breeding, choose qualified close shellfish earlier, regulate and control the synchronous maturation of close shellfish sexual gland through 10-15 days and lay eggs, be fertilized and carry out the scallop larval culture then, adhere to into juvenile mollusk through the metamorphosis of 13-18 days scallop seedling, juvenile mollusk carried out the sea after indoor foster 10-15 days temporarily keeps a full stand of seedings, and carries out the mariculture of branch cage November, begin results in September, second, up to the seawater in the 3rd year before the megathermal period.

2, chlamys farreri seed breeding in autumn and form method, its concrete grammar and step:

1) grow seedlings in the selection of time of chlamys farreri seed breeding and autumn and prepare to select to begin to carry out mid-August in autumn to September usually the seed breeding of chlamys farreri;

2) the chlamys farreri seed breeding is supported with temporary with the screening of close shellfish, be mid or late August to choose individual health, gonad development good close shellfish, stocking density will be controlled at below every cube of water body 30-50, can adopt cylinder mould to hang to support or buoyant raft is supported temporarily, an amount of qi of chong channel ascending adversely, flowing water or every day need be changed water 1-2 time entirely, and the flat algae of in batches throwing something and feeding, chrysophyceae or other particulate artitificial food, nurturing period needs often to remove close shellfish excreta and reject dead sick shellfish, generally, just can breed gonad development close shellfish essentially identical to be produced through 10-15 days raising raising under 17.5-21 ℃ of condition of water temperature;

3) close shellfish to hasten parturition and be fertilized then be to select the good male and female of gonad development parent shellfish respectively, dry in the shade about 30 minutes, female shellfish is put into spawning pond and hastens parturition, an amount of qi of chong channel ascending adversely, water temperature 22-23 ℃; Surplus bucket or small-sized tank row essence, an amount of qi of chong channel ascending adversely, about 20 ℃ of the water temperatures put into only of male shellfish 30-50.Treat can inseminate after the smart ovulation peak period, sperm quantity is controlled at each ovum and adheres to 5-7 sperm and be advisable;

4) the scallop larval culture is with conventional basic identical, but should guarantee technically to cultivate density 8/more than the ml, and coolant-temperature gage remain on 17-21 ℃ or natural temperature all can, cultivated through 12-15 days and can throw in adherance;

5) to form then be the juvenile mollusk that chlamys farreri autumn seedling is bred to chlamys farreri autumn seedling, carries out the branch seedling in mid-November and form, and daily management is identical with the scallop culture of growing seedlings spring;

6) results generally need all can gather in the crops in September-November, and harvest time can extend in the July, the 3rd.