The nine-hole abalone is a kind of attachment and benthic molluscs. It belongs to molluscs in terms of taxonomy. It is a former Yagang steel, primitive gastropod, Baoke, and genus Bao. The shell is flat and its tower is located at the back of the body. It extends from the spiral hole column to the front shell edge and opens at the front of the body. There are about 6 to 9 holes. Covered by the inner secretory nacre, the shells inhabit the surface of the intertidal zone and reach water depths of 6 meters, and they prefer to live in the dark rocky pores. Its distribution area includes warm sea areas such as Japan, South Korea, southern China's coasts, and Taiwan. It is adapted to a high temperature and salinity water environment and has grown well in summer. However, the adaptability to low temperature is poor, and the optimum growth temperature is 20°C to 28°C. When the water temperature is lower than 15°C, the growth rate is significantly decreased. If the temperature is lower than 10°C for a long time, it will easily cause a large number of deaths. Nine hole abalone compared with local variegated abalone has the characteristics of rapid growth, large individual and excellent quality.
1 Nine hole hole nursery technology
1.1 Selection of breeding sites Choosing an area close to the source of water can reduce the cost of the dredge line, low power consumption, and large amount of water. Pay attention to the quality of water sources. Seedlings are suitable for growth in seawater with a salinity of 28 ‰ to 35 。.
1.2 Breeding method Nine borer breeding season from July to November, the peak period is from August to October.
1.2.1 seed selection. Individuals with intact, non-invasive, and non-adherent objects should be selected. Nine hole abalone dioecious, maturity in accordance with the degree of fullness of the reproductive nest to judge, the greater the fullness of sperm and ovary, the more mature. The species to be used for reproduction is preferably 2 to 3 years old. The reproductive nest is located on the side of the ventral foot. If you open the ventral foot, you can see the reproductive nest that resembles a horn. The male nest's reproductive nest is milky or slightly yellow in color. Shellfish's reproductive nest is purple or dark green, and the male and female ratio is 3:1 or 4:10.
1.2.2 Cleaning. The shells of the shells often obtained in the aquaculture ponds are often accompanied by sludge or excreted sediments. Therefore, these eggs should be cleaned before the eggs are collected to avoid mixing of eggs and sludge and affect the hatching rate. When cleaning, you can use the brush to brush off dirt on the shell surface, but you can not brush to the stomach part, otherwise the species shell is very vulnerable.
1.2.3 dry out. Place the cleaned shellfish in a cool place with the shell facing down and the stomach feet up for 0.5 to 1.5 hours. In order to make male and female progenitors discharge products at the same time, females are 0.5 hours older than the male.
1.2.4 Physical stimulation of spawning and production. The UV lamp is directly irradiated with pro-Balthy seawater at a dose of 300-800 mWh/L. Thereafter, the light bulb (220V, 40-60W) set at 20-30 cm away from the water is turned on (with illumination and temperature rise). The role). This method is simple and the productivity is higher than that of ultraviolet irradiation alone. However, the UV lamp irradiation time should be strictly controlled so as not to harm the pro-Bau. This method can elicit labor during the day, which greatly facilitates operation and observation.
1.2.5 Semen collection. The fertilization process is completed within 1 hour of spawning and fertilization, and the sperm and egg activity begins to decrease, which directly affects the hatching rate.
1.2.6 washing eggs. The siphon method is used to suck the eggs out of the ovary, so they are put into 40 to 50 liters of water tanks, with 600,000 to 800,000 eggs per carton (15 to 20 capsules per millilitre of water or 2400 to 500 eggs per cm above the bottom). Suitably), add 15 to 20 ml of the diluted serum. The amount of sperm should be appropriate, generally attract a small amount of eggs under the microscope, there are several sperm in the periphery of each egg membrane. Use a 300-mesh sieve to make a fishing net, pour the eggs into the net, and rinse slowly. Washing eggs is generally completed before the embryo develops to a 16-cell stage.
1.2.7 Eggs. The hatching density should be controlled at 15-20/ml or 400-500/m2 at the bottom. Incubation temperature above 22°C. At a water temperature of 26°C to 27°C, fertilized eggs develop to tandem larvae after 6 to 7 hours; 12 to 15 hours (after fertilization) develop to face plate larvae; 43 to 46 hours after fertilization can develop to early stages. Larvae.
1.2.8 Adherence period manual management. It can be moved into the nursery pool when it develops into the face plate larvae in the hatchery. The density of the larvae is controlled at 1-3/ml. The seedlings were hung on the nursery pond to allow the larvae to attach. Do not change the water while the larvae are floating until they are attached, but they should be properly inflated and the larvae can be inflated after running. The picking plate is the indispensable attachment base for the larvae to enter the pupa life. At the same time, benthic diatoms are attached to the plate to provide the larvae with the source of the diet. Diatoms must be inoculated before harvesting.
Benthic diatoms are preferably nave and algae. Practice has proved that the diatom culture environment light in the 2000 ~ 3000 lux, while the use of a good light transmission material as the attachment base for running water culture, the effect is good. However, the growth of diatom bait is relatively slow. When the amount of larvae attached is greater than the limit load of the bait board, the “white board†phenomenon will occur prematurely, so that if the juvenile abalone does not reach the peeling specification, no bait will be eaten. In addition, it is generally found that the seedling pool water from the brown to talk about or seedling board color change should promptly pay attention to fertilization or inoculation of diatoms. Also pay attention to the gas supply, gas must be sufficient to ensure that there is enough dissolved oxygen in the pool.
1.2.9 Stripping. When the length of the shellfish on the plastic wave plate is 0.6 to 0.7 cm, the net cage is started to be stripped and cultivated after peeling off. Initially, it is mainly fed with river hedgerows and feeds, and it is fed once every 1.2 days in the summer and once every 2 to 3 days in the winter. The daily exchange volume of pool water depends on 250%-300% of the entire pond water body. When peeling, try to make the size separate. Uneven size will affect the survival rate and growth rate. When the abalone reaches 1.5 to 2 centimeters or more, it can enter the management stage.
3 nine hole abalone breeding
3.1 Abalone Breeding Management The juvenile Bao Baobao box will enter the management stage of growing up. At this time, controlling the culture density after stripping is the key to ensure the rapid growth of abalone seedlings. The recommended density is: 1.5 to 2.0 cm, 50/cage 33.5 to 4.0 cm, 30 to 40 / Cage; 4.5 to 5 cm, 20 to 30/cage. The box has a cuboid of 0.40.30.1 cubic meters in size. All six surfaces are injection molded into a mesh shape to ensure good water flow and a movable door on one side.
The discharge of the cages is stacked in groups of about 10 and 20 in a row to ensure good water flow and a movable door on one side. The discharge of the cage is about 10 stacked in a string, 20 in a row, and an aeration tube is installed under each row of cages. The bottom layer is about 20 cm away from the bottom of the tank. A walkway is left in the middle of each row of cages, and the width of the walkway is about 70 cm. All the doors should be oriented towards the channel for easy management. The southern Baochi ponds are mostly rectangular cement pools, and the single pools are generally 1.2 to 1.7 meters deep, and an area of ​​20 to 40 square meters is appropriate. Lay the trachea at the bottom of the bottom cage. The water supply capacity must be more than 5 times of the aquaculture water to keep the water flowing day and night. Although the supply of gas according to the surface of the water surface evenly tumbling out is appropriate (water depth is less than 1.5 meters use 20 to 35 kPa, more than 1.5 meters use 35 to 50 kPa), the entire breeding process must not stop gas.
Cultivation requires that the amount of water changed every day is 3 to 5 times the amount of water. One manifestation of the lack of water and gas for growing abalone is the slow growth of abalone and the whitening of the body's spiral. Although this method has a large investment, the output per unit of water is 5-6 times higher than that of a plane cage culture, and the breeding cycle is short.
3.2 The feed is dominated by river fences (fine bases and ramifications). When there is no river fence, frozen salted kelp and dry seaweed are used instead. Dried kelp, algae, and horseweed are not favored. The seaweeds also have good growth effects. The dishes must be fresh and clean to prevent pollution. Promoting three-pointed hunger and seven-point fullness when feeding, and feeding too much harm is more than benefits, not only waste of feed, can not eat the food is also easy to degenerate rotten, causing the incidence of abalone. It is advisable to feed a small amount of ground nutrients, generally feeding the vegetables once every 4 days in the higher temperature season and feeding them once every 7 days in the winter season. About 100 g/(cage), should be based on the size and seasonal changes of abalone. In short, there should be no leftovers.
3.3 Hygienic management The health management of Jiu Bao abalone has two aspects.
3.3.1 Hygienic management of tools and equipment. All tools and equipment used for abalone farming, such as abalone boxes, buckets, water basins, scoops, pressure bricks and boxes, pad box brackets, and culture ponds, must be cleaned before use, and then disinfected with potassium acid, and then The use of the line, and in the use of regular cleaning and disinfection. Each time the feed tanks, aquariums, bricks, etc. are combined, they should be thoroughly cleaned. Especially in the hot season, health management should be strengthened.
3.3.2 Hygienic management of feed. After the arrival of the dish, it should be cleaned immediately, and then the inflatable water in the deceased pool should be kept for future use. The dish must be fresh and not stored for too long. If it is found that the food is deteriorating, it cannot be used anymore. Each time you feed the dish, you must take out the previously uneaten food and thoroughly rinse the box and feed it again. In addition, dishes must not be immersed in fresh water or rain, but once the dish has been invaded with fresh or rain, it will cause abundance of death in abalone's digestive system.
3.3.3 Bao Bao’s merchandise management. The cultivated abalone grows to more than 5 cm in length and can be sold as a product. There are several issues that should be noted when selling goods. Abalone is susceptible to disease at the turn of spring and summer until late October. During this time, abalone should not be easily toggled. If you want to sell goods, you must sell the abalone that you dialed. Other abhorrent sellers should not be tossed. Generally into the winter can be completed for the sale of a complete classification of Bao. First of all, the pro-Bun used for culture can be selected and boxed separately, and the female and male sub-pools can be raised to prepare the seedlings for raising the temperature. Other products can be packed into the pool by large, medium and small containers for sale.