Tachypleus tridentatus Leach is a member of the arthropod and has a chewing gum subdoor. Gangu Gang Gang, sword tail head. With a history of more than 400 million years, it is commonly known as the "living fossil." Currently, there are four main species in the world: Dong Fang, American Ape, Malayan, and Yuan Mei. Oriental oysters are mainly distributed in the west of the Japan Sea, south of the Yangtze River estuary in China, and along the east of the Indo-China Peninsula. Its blood is blue, the current market price after processing is 60,000 US dollars / gallon, which has high medical and scientific value.
First, basic biological characteristics
1. The mature oriental carcass is 30cm-60cm in length. The females are larger than males and the sex ratio is 1:1. The body is divided into three parts: breastplate, plastron, and swordtail. The swordtail resembles a triangular spatula and is its defensive weapon; its abdomen has several paddle-shaped abdominal limbs for swimming and breathing; its mouth is in the middle of the head breastplate and has a pair of clamp-like appendages. To assist in feeding, there are 10 appendages around the mouth. The first four appendages of the females have pliers. The males have hooks. This is one of the differences in the shape of the female and the male. At the same time, there are two intaglios at the front of the male breastplate.
There are four eyes in the oriental eel, and there are two small eyes with 0.5mm at the front of the head breastplate. They are used to sense the brightness. There are a pair of big compound eyes on both sides of the head breastplate, which consists of several small eyes and has a change in vision. Sharpness features.
2. Living habits Natural conditions, the Oriental magpies are calm, the bottom of the sand, mud as the base of the shallow bay life, in the breeding season after late June, the female mastiff than its thin and powerful, double into On the shallow bay beach to breed eggs.
3. Breeding (1) Egg-laying The oriental otter spawns in the season from late June to late August, especially during the most prosperous periods. During spawning, the females spawn on the mudflats with 10cm to 15cm deep at the diggings. At the same time, the males on the back of the females also begin to row and perform in vitro fertilization. Between a period of time, the two advance 10-15cm again and build another "love nest." There are tens of thousands of eggs laid by females.
(1) The characteristics of fertilized eggs and larvae of each stage fertilized eggs: spherical sunken eggs, egg diameter 2.8-3.4mm, outside a layer of yellow opaque egg shell.
蜕 蜕 蜕 蜕 period: fertilized eggs about 15 days to remove the outer shell, egg diameter 2.8-3.4mm. The fertilized eggs are still surrounded by a transparent layer of keratinocytes; this shows that the larvae of the larvae in the membrane are raised and the central ridge of the chest is clear. There are 3 pairs of chest limbs that can move within the membrane and produce a second layer of keratinocytes.
In the omental period, about 30 days later, the first layer of keratinocytes is pulled out and the egg diameter is 5-5mm. At this time, the boundary between the central ridge of the larvae and the lateral ridges of the cheeks is more pronounced, showing a trilobal shape. The plastron is more transparent, with two leaves in the left and right. The caudal primordium appears between the left and right plastrons, and the chest and limbs increase to 5 pairs.
Trilobal larval stage: About 60 days after the removal of the first layer of keratinocytes, the second layer of cuticles is removed, which is trifoliate larvae. The larvae are flat at this time, and the major axis and the horizontal axis are almost equal to 5.9-5.8 mm. Body white, the front edge of the left and right sides of the head breastplate has a dark-brown arc-shaped line, and the pair of compound eyes is located at both ends of the arc line. There is a pair of monocular eyes at the front center of the head breastplate. The plastron heals and heals, with the back end 6 pairs of nicks and the lateral edge with 1 side thorn. There were 6 pairs of chests and 8 sections on the abdomen, and 1 pair of flaky abdomen limbs on each dry festival. The larvae showed a volatility of movement during the time, mainly in the state of volts.
Post-larval stage: the larvae grow in pupa. The first larva before the hull is called post-larvae. Its cephalothorax and plastrons are gradually curved toward the ventral surface. The body color is darkened, and the vertical axis of the body grows to 6.5mm. The plane length of the horizontal axis is only 5.0 mm, and it takes about 60 days for the trilobite larvae to develop the yoke larvae.
Aberdeen: After the first post-larvae were oyster shells, they were called Aberdeen. When the oyster shell is first cracked from the front edge of the cephalothorax, then the larvae dig out from the old shell. The distinctive feature of Aberdeen is the 2.4mm long sword-shaped tail at the rear edge of the plastron. The plastron is hexagonal, each side has a notch on each side, and each has a thorn. At this time, the longitudinal axis of the individual is 10.2 mm and the horizontal axis is 7.7 mm. Aberdeen is no different from the adult in morphology, but the female's secondary sexual characteristics (two four-points on the front of the head breastplate) have not yet appeared.
II. Artificial Breeding Techniques of Dong Fang
1. Intimate choice: During the spawning season of May to July each year, you can buy or go to the shallow beach to catch the pro-spawn who will be spawning, choose a large and robust, clean the body surface, about 4kg per female, 2kg per male Individual.
2. Intimate into the pool: intimacy culture pool (also spawning pool) can use the general small cement pool, bottom shop about 10cm sand, top shading. The pro-chondrites were sterilized with 30ppm formalin for 10 minutes before entering the pond. The stocking density was 2kg-3kg/m2, and the control water level was 50cm-80cm. Microinflated.
3. Intimate management; intimacy rarely feeds during the egg production period, so do not do feeding or a small amount of bait during the pro-growth culture. For feeding, small amounts of shrimp or fish can be fed at night. Change the water every 3 days in the culture pool, change the amount of water to 100%, and remove residual baits. Control water temperature 23-26 °C, salinity 25-30‰, pH 7.8-8.2, keep the water fresh.
4. Collection and incubation of fertilized eggs Each time the water is changed, the fertilized eggs are hand-picked from the fine sand at the bottom of the spawning tank to remove the bad eggs and the transparent unfertilized eggs. The fertilized eggs are placed in glass steel drums or small hatchery tanks. The bottom is inflated and kept dark. The water temperature is controlled at 25-28° C., the pH is 8.0-8.3, and the salinity is 25-30 ‰. Change 20% of water every day, and “pour pool†according to water quality. The hatched trifoliate larvae must be promptly moved to the larval rearing tank.
5. The larvae cultivate the larvae and the cultivating pool can use cement pools of different sizes, the bottom bury 2cm-3cm of fine sand, add some rubble or small stones for hiding the young cubs, control the water level 50-80cm, change the water 20%-30% every day , Water temperature 25 °C -28 °C, salinity 25-30 ‰, pH 7.8-8.3; cleaning sand at intervals. Baits are mainly rotifers, larvae, and copepods, and they are fed with Planellaella to regulate water quality. Observe the feeding condition of the cubs at any time and adjust the type and quantity of bait.
Third, discuss and analyze
1. About fertilized eggs. The quality of fertilized eggs was good in the previous period, and the hatching rate was high. In the later period, the fertilized eggs were mostly white or light yellow, the eggs were soft, and the hatching rate was low.
2. Baby food. The habits of cubs are similar to those of adults and they inhabit the bottom of the body of water. According to the life style of crustaceans, the author believes that the bait series is mainly composed of single-cell algae, rotifers, larvae of Artemia, and copepods. As to which kind of open bait is appropriate, and the type and amount of bait in various stages of the calf, it needs to be further studied.
First, basic biological characteristics
1. The mature oriental carcass is 30cm-60cm in length. The females are larger than males and the sex ratio is 1:1. The body is divided into three parts: breastplate, plastron, and swordtail. The swordtail resembles a triangular spatula and is its defensive weapon; its abdomen has several paddle-shaped abdominal limbs for swimming and breathing; its mouth is in the middle of the head breastplate and has a pair of clamp-like appendages. To assist in feeding, there are 10 appendages around the mouth. The first four appendages of the females have pliers. The males have hooks. This is one of the differences in the shape of the female and the male. At the same time, there are two intaglios at the front of the male breastplate.
There are four eyes in the oriental eel, and there are two small eyes with 0.5mm at the front of the head breastplate. They are used to sense the brightness. There are a pair of big compound eyes on both sides of the head breastplate, which consists of several small eyes and has a change in vision. Sharpness features.
2. Living habits Natural conditions, the Oriental magpies are calm, the bottom of the sand, mud as the base of the shallow bay life, in the breeding season after late June, the female mastiff than its thin and powerful, double into On the shallow bay beach to breed eggs.
3. Breeding (1) Egg-laying The oriental otter spawns in the season from late June to late August, especially during the most prosperous periods. During spawning, the females spawn on the mudflats with 10cm to 15cm deep at the diggings. At the same time, the males on the back of the females also begin to row and perform in vitro fertilization. Between a period of time, the two advance 10-15cm again and build another "love nest." There are tens of thousands of eggs laid by females.
(1) The characteristics of fertilized eggs and larvae of each stage fertilized eggs: spherical sunken eggs, egg diameter 2.8-3.4mm, outside a layer of yellow opaque egg shell.
蜕 蜕 蜕 蜕 period: fertilized eggs about 15 days to remove the outer shell, egg diameter 2.8-3.4mm. The fertilized eggs are still surrounded by a transparent layer of keratinocytes; this shows that the larvae of the larvae in the membrane are raised and the central ridge of the chest is clear. There are 3 pairs of chest limbs that can move within the membrane and produce a second layer of keratinocytes.
In the omental period, about 30 days later, the first layer of keratinocytes is pulled out and the egg diameter is 5-5mm. At this time, the boundary between the central ridge of the larvae and the lateral ridges of the cheeks is more pronounced, showing a trilobal shape. The plastron is more transparent, with two leaves in the left and right. The caudal primordium appears between the left and right plastrons, and the chest and limbs increase to 5 pairs.
Trilobal larval stage: About 60 days after the removal of the first layer of keratinocytes, the second layer of cuticles is removed, which is trifoliate larvae. The larvae are flat at this time, and the major axis and the horizontal axis are almost equal to 5.9-5.8 mm. Body white, the front edge of the left and right sides of the head breastplate has a dark-brown arc-shaped line, and the pair of compound eyes is located at both ends of the arc line. There is a pair of monocular eyes at the front center of the head breastplate. The plastron heals and heals, with the back end 6 pairs of nicks and the lateral edge with 1 side thorn. There were 6 pairs of chests and 8 sections on the abdomen, and 1 pair of flaky abdomen limbs on each dry festival. The larvae showed a volatility of movement during the time, mainly in the state of volts.
Post-larval stage: the larvae grow in pupa. The first larva before the hull is called post-larvae. Its cephalothorax and plastrons are gradually curved toward the ventral surface. The body color is darkened, and the vertical axis of the body grows to 6.5mm. The plane length of the horizontal axis is only 5.0 mm, and it takes about 60 days for the trilobite larvae to develop the yoke larvae.
Aberdeen: After the first post-larvae were oyster shells, they were called Aberdeen. When the oyster shell is first cracked from the front edge of the cephalothorax, then the larvae dig out from the old shell. The distinctive feature of Aberdeen is the 2.4mm long sword-shaped tail at the rear edge of the plastron. The plastron is hexagonal, each side has a notch on each side, and each has a thorn. At this time, the longitudinal axis of the individual is 10.2 mm and the horizontal axis is 7.7 mm. Aberdeen is no different from the adult in morphology, but the female's secondary sexual characteristics (two four-points on the front of the head breastplate) have not yet appeared.
II. Artificial Breeding Techniques of Dong Fang
1. Intimate choice: During the spawning season of May to July each year, you can buy or go to the shallow beach to catch the pro-spawn who will be spawning, choose a large and robust, clean the body surface, about 4kg per female, 2kg per male Individual.
2. Intimate into the pool: intimacy culture pool (also spawning pool) can use the general small cement pool, bottom shop about 10cm sand, top shading. The pro-chondrites were sterilized with 30ppm formalin for 10 minutes before entering the pond. The stocking density was 2kg-3kg/m2, and the control water level was 50cm-80cm. Microinflated.
3. Intimate management; intimacy rarely feeds during the egg production period, so do not do feeding or a small amount of bait during the pro-growth culture. For feeding, small amounts of shrimp or fish can be fed at night. Change the water every 3 days in the culture pool, change the amount of water to 100%, and remove residual baits. Control water temperature 23-26 °C, salinity 25-30‰, pH 7.8-8.2, keep the water fresh.
4. Collection and incubation of fertilized eggs Each time the water is changed, the fertilized eggs are hand-picked from the fine sand at the bottom of the spawning tank to remove the bad eggs and the transparent unfertilized eggs. The fertilized eggs are placed in glass steel drums or small hatchery tanks. The bottom is inflated and kept dark. The water temperature is controlled at 25-28° C., the pH is 8.0-8.3, and the salinity is 25-30 ‰. Change 20% of water every day, and “pour pool†according to water quality. The hatched trifoliate larvae must be promptly moved to the larval rearing tank.
5. The larvae cultivate the larvae and the cultivating pool can use cement pools of different sizes, the bottom bury 2cm-3cm of fine sand, add some rubble or small stones for hiding the young cubs, control the water level 50-80cm, change the water 20%-30% every day , Water temperature 25 °C -28 °C, salinity 25-30 ‰, pH 7.8-8.3; cleaning sand at intervals. Baits are mainly rotifers, larvae, and copepods, and they are fed with Planellaella to regulate water quality. Observe the feeding condition of the cubs at any time and adjust the type and quantity of bait.
Third, discuss and analyze
1. About fertilized eggs. The quality of fertilized eggs was good in the previous period, and the hatching rate was high. In the later period, the fertilized eggs were mostly white or light yellow, the eggs were soft, and the hatching rate was low.
2. Baby food. The habits of cubs are similar to those of adults and they inhabit the bottom of the body of water. According to the life style of crustaceans, the author believes that the bait series is mainly composed of single-cell algae, rotifers, larvae of Artemia, and copepods. As to which kind of open bait is appropriate, and the type and amount of bait in various stages of the calf, it needs to be further studied.