Three major abalone varieties
(1) Haliotis discus hannai: The shell is large and thick, with three layers of spiral, shallow suture and blunt top. There is a row of protrusions on the edge of the shell, with 4-5 openings at the end, and a groove parallel to the protrusions near the outside of the protrusions. The outer surface of the shell is dark brown-green, with obvious growth lines and no large pleated walls, while the inner surface of the shell is silvery white.
Physical Agriculture in Dalian: Physical Methods and Applications of Abalone Feeding (1)
(2) Haliotis diversicolor: the spiral layer is three layers, and the suture line at the base is deep, which gradually becomes inconspicuous towards the top. The top of the shell is blunt, slightly lower than the height of the snail layer, and the adults are mostly corroded, revealing pearl luster. From the top of the shell down, from the middle of the second spiral layer to the end edge of the body spiral layer, there is a row of protrusions, about 20 * * *; There are 7-9 openings near the edge of the spiral layer. The inner surface of the shell is silvery white with pearl luster.
Physical Agriculture in Dalian: Physical Methods and Applications of Abalone Feeding (1)
(3) Haliotis diversicolor: Living habits are similar to those of Haliotis diversicolor. The shell surface is green-brown, yellow-brown, with purple markings, and the inner surface of the shell is silver, belonging to warm water species, which is produced in Taiwan Province Province, Hainan Province and the Western Pacific Ocean.
Physical Agriculture in Dalian: Physical Methods and Applications of Abalone Feeding (1)
Section 1 Ecological Habits of Abalone
First, the living habits of abalone
(1) human settlements
Bao likes to live in the rocky area with gentle tidal current, clear water quality and algae growth in the offshore waters. .
The depth of abalone habitat is related to species and individual size. Haliotis diversicolor1~ 20m, Haliotis discus hannai mostly inhabits 2 ~10m, and Japanese giant abalone inhabits 50m. Young abalone generally lives in the depth of nearshore 1 ~ 3 meters, while adult abalone lives in deeper waters.
Rock reef is the basic surface for abalone to absorb and crawl, and it is an indispensable environmental condition for abalone to inhabit. The habitat of abalone is closely related to the different shapes of rocks. Japanese scholars divide abalone habitats on rocky reefs into five types: cave type, shed type, concave type, underwater type and open-air type.
(2) Crawling habit
With the help of wide feet, flat surface and its creeping function, abalone is adsorbed on rock reefs and crawls in reef sheds and caves. Although the wind and waves are very heavy, it is difficult to photograph it. Abalone crawls faster and can move 50 ~ 80 cm per minute. Abalone has a strong adsorption capacity. An abalone with a shell length of 15 cm can reach about 200 kg after complete adsorption.
Bao's life has the habits of staying in the daytime and going out at night, seasonal sports and deep and shallow sports.
(3) The feeding habits of abalone
1, feeding of creeping larvae and juvenile abalone
Before the abalone larvae enter the crawling stage, that is, the planktonic life stage, they mainly rely on the yolk material provided by the mother in the egg cell as the energy source needed for development. Therefore, the artificial culture of abalone generally does not need to feed any bait at the stage of planktonic larvae. Abalone larvae obviously feed after crawling stage. At first, creeping larvae and young abalone could only feed on the attached navicular algae and ovoid algae with the diameter of 10 ~ 15 micron. As it grows, it can eat bigger diatoms and some algae and organic debris.
2. Feeding young abalone and adult abalone
Young abalone over 5 mm began to eat small and tender seaweed as food, such as Enteromorpha prolifera, Ulva lactuca, Undaria pinnatifida and kelp leaves.
Adult abalone is omnivorous, but it mainly eats brown algae, red algae, green algae and attached diatoms.
In addition to choosing different kinds of bait, abalone usually likes to eat tender seaweed.
Eating different kinds of algae will also affect the color of the shell surface, especially when feeding different kinds of single bait, the color change of the shell surface is particularly obvious.
The feeding habits of abalone are the same as those of abalone, and there are also diurnal and seasonal changes.
The consumption of abalone also varies greatly in seasons.
Physical Agriculture in Dalian: Physical Methods and Applications of Abalone Feeding (1)
Section II Propagation and Growth of Haliotis diversicolor
First, reproduction
(1) During the breeding period, the gonads of Haliotis diversicolor in Dongshan, Fujian Province developed and matured successively from May to August when the water temperature was 24 ~ 28℃. The peak period of breeding is from mid-May to late June at 25-26℃, and July is the continuation stage of late breeding.
Bo Huang marine Haliotis discus hannai began to breed in July and August when the water temperature was 20-24℃. After moving south to Dongshan, Fujian, the suitable breeding temperature has no obvious change for two years. When the water temperature is 2 1-24℃, it will breed in April-May. . The water temperature at which the gonad of Haliotis discus hannai begins to develop is 7.6℃.
(2) Reproductive habits
In the group composition of abalone, females are slightly more than males, and they begin to breed around the age of three. The minimum oviposition biology of Haliotis diversicolor is 35 mm, and that of Haliotis discus hannai in Yellow Sea and Bohai Sea is 43-45 mm. ..
When sexually mature, the male gonad is milky yellow and the female is dark green. It can be distinguished by lifting the foot and the mantle without dissection.
When sperm and eggs are discharged, germ cells enter the right renal cavity from gonads, pass through the respiratory cavity, and then are discharged from the body through the water outlet.
The number of eggs laid by female abalone is related to individual size. The number of eggs laid by individuals over 8 cm can reach 6.5438+0.2 million, and the number of eggs laid by individuals around 6 cm is generally around 800,000, and the maximum number of eggs laid by individuals can reach more than 2 million.
(III) Germ cells
1. Observe the tissue section of immature ovary with a diameter of 40-70 microns. The diameter of mature egg cells is as long as 100-270 microns.
In the case of artificially induced spawning, eggs are often discharged in short cylinders or dung blocks. The size of eggs varies from species to species. Generally, the egg diameter of the egg-containing membrane is 200-280 microns, the egg yolk diameter is 160- 180 microns, the abalone egg diameter is 200 microns, and the egg yolk diameter is 180 microns. The mature eggs of abalone are slightly lighter in plant color and thicker in animal color, and the egg membrane is covered with colloid, which still exists until the larvae hatch.
2. Sperm released after sperm maturation can be divided into head, middle and tail. About 60 microns long. Mature sperm stored at 22-23℃ for more than 3 hours, the vitality is obviously weakened, but it is still alive.
3. Embryogenesis and larval development
(1) roller base
(2) larvae of panel
(3) Perioral larvae
(4) Reptile larvae in the upper foot differentiation stage
(5) Young abalone
Second, growth.
(1) growth
1 Larvae growth During the larval development of Haliotis diversicolor in China, it takes about 10/0 hour for trochophore to develop into a larva, and the individual grows 20 microns every day under the conditions of average water temperature of 27℃ and seawater specific gravity of 1.022- 1.023. It takes 1.5 days from the initial crawling larva to the enclosure stage, and the individual grows 15 microns every day. It takes about 9 days for crawling larvae to develop from peripodal shell stage to suprapodal differentiation stage, and individuals grow 50 microns every day. After the differentiation of the upper foot, the individual growth is gradually accelerated, with an average growth of more than 80 microns per day. It takes 24.5 days for young abalone to grow faster, with a shell length of 65438 0.85 mm and an average daily growth of 67 microns. The larvae of Haliotis discus hannai developed to the juvenile stage, the shell length was 2.35 mm, and the average daily growth was about 63, which was not significantly different from that of Haliotis diversicolor larvae.
2. Growth of juvenile abalone and juvenile abalone
It takes 24 days for Haliotis diversicolor to appear the first breathing hole. The shell is 2.00-2.26 mm long, with 22-23 pairs of upper foot protrusions and 2 breathing holes. At this time, the inner surface of the shell began to appear pearl luster. The 32-day-old shell is 2.52 mm long and has 34 pairs of upper foot protrusions and 4 breathing holes. The color of the shell is reddish brown and flame-shaped (the color of the shell back varies with the type of bait). The 60-day shell is 5.9 mm long and has 1 1 breathing holes. 67 days, the shell is 7.6 mm long and 5.2 mm wide, with 13 breathing holes. The tentacles of the head are whiplike and yellow, the protrusion of the upper foot is obviously enlarged, and black pigment appears on the snout.
With the growth of individuals, the number of breathing holes in Haliotis diversicolor is increasing. Finally, due to the functional relationship, only 5-6 are kept, and others are gradually closed.
3. Growth of adult abalone
Abalone with a shell length of 3-5 cm grows faster.
(2) Factors affecting growth
1, bait
2. In a suitable temperature range, the growth rate of young abalone and adult abalone also increased with the increase of temperature.
Section III Artificial Propagation of Abalone
First, the female abalone is heated to promote ripening and storage.
(1) Meaning In the north, the natural spawning season of Haliotis discus hannai is usually in July, and the sea water temperature and air temperature will be in a high temperature period, which is not conducive to the culture of benthic diatoms such as navicular algae and nitzschia, and affects the development and growth of young abalone, resulting in high mortality. In addition, when the water temperature drops in winter, the juvenile abalone is small (generally the shell length is below 1 cm), and the mortality rate of overwintering in the sea is extremely high. In order to meet the feed needs of young abalone, it is an important technical measure in production to prolong the growth period before overwintering, improve the survival rate of overwintering, raise the temperature of parent abalone and lay eggs and raise seedlings early.
(2) Basic requirements of equipment
The nursery pond suitable for heat preservation and light control is selected as the heating storage pond for parent abalone. Parent abalone can be placed in a cage and hung in the pool, or dark plastic plates or tiles can be placed at the bottom of the pool to make an arched nest for parent abalone to inhabit. The swimming pool should be equipped with inflation, heating and temperature control devices.
(3) The starting time of ripening and storage.
According to relevant reports, the effective accumulated temperature of abalone sexual maturity is above 1000℃, which is calculated according to the following formula.
n
Yn=∑(Ti—7.6℃)
I= 1 Yn is the effective accumulated temperature, and Ti is the storage water temperature, that is, the effective accumulated temperature is equal to the sum of the daily storage water temperature of abalone during storage (excluding Ti < 7.6℃) minus the biological zero (that is, 7.6℃). Therefore, when the storage water temperature is 18-20℃, it takes about 3 months to make the effective accumulated temperature reach 1000℃, so the ripening storage of parent abalone should start 3 months before picking seedlings.
(4) Selection of parent abalone
The individual size of Haliotis discus hannai is above 8-9 cm, with strong physique, no trauma and keen foot muscle activity. The ratio of male to female is 4: 1.
(5) Storage capacity and density of parent abalone
The rearing amount of parent abalone is related to the age or individual size of parent abalone, especially to physical strength. Generally, each parent abalone can lay eggs 1 10,000, so the number of parent abalone can be determined according to the planned seedling collection. In order to obtain high-quality fish eggs, the number of parent abalone can be increased by 4-5 times. Storage density is related to storage conditions (such as ventilation). Generally, the storage density per cubic meter of water (about 2000 ~ 2500g) can store about 20 ~ 25 parent abalone.
(6) Storage and maintenance management
The daily management during storage is mainly heating, inflating, changing water and feeding. You can use closed tube heating or electric hot wire heating to raise the temperature by 2℃ every day and keep it constant when it reaches 20℃. Continuous aeration day and night, the aeration amount is about 6 ~ 8 liters/minute per cubic meter of water, so that the oxygen content of seawater is kept at 5.0 mg/liter. Move the cage (or nest) and change the pool every day 1 time, and the temperature difference of changing the pool should be less than 0.5℃. Feed 1 time every two days, and the feeding amount will increase with the increase of water temperature. When the temperature reaches 20℃, the feeding amount is generally about 20 ~ 30% of the total weight of parent abalone, and the specific feeding amount will increase or decrease according to the remaining bait amount in the cage.
Secondly, the cultivation of benthic diatoms.
Benthic diatom is the main bait of abalone larvae and juveniles, and whether it can meet the feeding needs of larvae and juveniles determines the success or failure of artificial breeding. Benthic diatoms are attached unicellular algae, and it is necessary to use a thin plate (or film) with good light transmittance as the attachment base.
(1) Selection of Algae Species
The benthic diatoms suitable for local reproduction and growth at that time can be selected as algae species, and generally, small navicular algae, nitzschia algae and crescent algae can be selected. These algae can be wiped off the nozzle of seawater with flowing water, or coated on the wall of the pond where seawater is stored, washed into a triangular bottle, cultured and selected. You can also hang the plastic film on the kelp culture raft, wait for 5-7 days to attach benthic diatoms, and then wash and inoculate. Or take back brown algae such as Sargassum thunbergii from the sea, wash it in filtered seawater, brush off epiphytic benthic diatoms, and filter the obtained algae liquid water into algae species by Nx 103 sieve. However, most of the algae obtained by this method are larger cuneiform algae, elliptic algae, rhomboid algae and so on. It can be used as a remedial measure for young abalone when the bait is insufficient before peeling.
(2) Inoculation and culture
Insert the bait tray (or membrane) sterilized by potassium permanganate or bleaching powder into the abalone seedling collecting rack (see the selection of seedling collecting tray for specifications), put it into the seawater filtered by ceramic filter (or the seawater filtered and disinfected by cotton) more than one month before seedling collecting, and add nutrients according to the requirements of single-cell algae culture (that is, n: p: Fe: Si = 20: 1: 65438).
In addition, seawater can also be filtered by screen mesh (Nx 103) and then enter the pond. Benthic diatoms brought in from seawater can be used as natural algae species, without additional inoculation, and only nutrients are added quantitatively according to the above method. After half a month, change half the water every three to five days, and then supplement the nutrition. However, this method needs to immerse the bait tray (membrane) in the pond 2 13 months before picking seedlings.
Strong light should be avoided during the culture process, otherwise green algae will multiply and benthic diatoms will be inhibited. The general illumination is 1000 ~ 2000 lux. The seedling collecting frame can be turned over repeatedly, which inhibits the reproduction of green algae to a certain extent.
Third, egg collection.
(A) the method of inducing stimulation
1. For the method of ultraviolet irradiation of seawater, there are two 30-watt ultraviolet lamps (generally 2-4 lamps are needed for standby), and the terminals at both ends of the lamps should be sealed with epoxy resin fingers to prevent water leakage. The size of the irradiation container (aquarium or small pool) is suitable for accommodating ultraviolet lamps, and the capacity is about 100-300 liters.
Irradiation method: the ultraviolet lamp tube can be directly placed in the water for irradiation, or it can be hung about 5 cm above the water. Inject the filtered fresh seawater into a water cluster box with a water depth of about 25 cm, cover the box with a black cloth to avoid ultraviolet radiation, and then turn on the light for irradiation. Practice has proved that 300 ~ 500 MW/L is good.
Irradiation dose (milliwatt hour/liter) = (germicidal lamp power (milliwatt) × irradiation time (hour))/irradiation water volume (liter)