Method for cultivating Octopus sinensis seedlings in ponds

Abstract

The present invention relates to a method for cultivating Octopus sinensis seedlings in a pond, belonging to the technical field of aquaculture. The method comprises preparation of a nursery pond, cultivation of bait organisms, seedling placement, bait feeding, and seedling harvesting. The method provides sufficient bait for early-stage Octopus sinensis seedlings by cultivating crab larvae in advance in the pond. The diversified bait organisms cultivated in the pond are utilized to provide rich nutrition for mid- and late-stage seedlings. The pond bottom soil can well simulate the natural habitat of Octopus sinensis larvae, effectively inducing the seedlings to burrow, and the larval burrowing rate can reach 10.5-11.2%.

Description

Technical Field

[0001] The invention belongs to the technical field of aquaculture, and particularly relates to a method for cultivating Octopus sinensis seedlings in a pond. Background Art

[0002] The Chinese octopus (Octopus sinensis), commonly known as octopus, octopus claw, red octopus, and sow octopus, belongs to the order Octopoda, family Octopodidae, and genus Octopus. It is primarily found in the temperate waters of the northwest Pacific Ocean and is an important commercial cephalopod species in my country. Its tender and delicious meat, high in protein, can be eaten raw or dried. Its medicinal properties, including nourishing blood and qi, and promoting astringency and muscle growth, make it a popular seafood delicacy and tonic. It is also a significant export, with a large consumer market in Japan and South Korea. Due to overfishing and environmental degradation, Chinese octopus stocks have been gradually depleted in recent years. To meet the growing market demand and protect wild Chinese octopus stocks, there is an urgent need to develop artificial breeding of Chinese octopus.

[0003] Currently, there are no breakthroughs in artificial breeding technology for Octopus sinensis. The main difficulty lies in the lengthy dorsification period of its larvae, which takes one to two months from the onset of dorsification to complete dorsification. This process results in a very high mortality rate for larvae, a key technical bottleneck that prevents the full artificial breeding of Octopus sinensis. Therefore, developing breeding techniques that can increase the dorsification rate of larvae is of great significance to the development of the Octopus sinensis breeding industry. Summary of the Invention

[0004] The present invention provides a method for cultivating Octopus sinensis seedlings in ponds. By cultivating crab larvae in advance in a pond, sufficient bait is provided for early-stage Octopus sinensis seedlings. Diversified bait organisms cultivated in the pond are used to provide rich nutrition for mid- and late-stage seedlings. The pond bottom soil can well simulate the natural habitat of Octopus sinensis larvae, effectively inducing the seedlings to burrow on the bottom, and significantly improving the larval burrowing rate.

[0005] The present invention is accomplished by the following operating techniques:

[0006] A method for cultivating Octopus sinensis seedlings in a pond, comprising preparing a seedling pond, cultivating bait organisms, planting seedlings, feeding bait, and harvesting seedlings;

[0007] Preparation of the nursery pond: the water temperature of the nursery pond is 20-28°C, the salinity is 31-35, the bottom of the pond is gravel, and it is exposed to the sun for 10-15 days before use; 7-10 days before stocking, add 20-30cm of water and disinfect it;

[0008] Cultivation of the bait organisms: a bottom microporous aerator is arranged in the pond, and a nylon mesh and a small earthenware pot are placed at the bottom of the pond to shelter the larvae; water is added to a depth of 1.5 to 2 meters, and chlorella is inoculated. Nitrogen fertilizer is sprayed every day until the pond water turns dark green, and then rotifers are inoculated;

[0009] When the density of rotifers in the pond reaches 8-10 / ml, put the strong and vigorous egg-bearing crabs into the nursery pond; on average, every 30-50m 3 Release one brooding crab. After the crab larvae hatch, maintain the concentration of Chlorella and rotifers in the nursery pond to provide food for the hatched crab larvae.

[0010] The seedling distribution method is as follows: when the density of crab zoeae in the nursery pond reaches 0.2-0.5 / ml, the crab parents are taken out from the nursery pond and the Chinese octopus seedlings are distributed; the hatched Chinese octopus larvae are evenly distributed in the nursery pond, and the number is controlled at 1000-2000 / m 3 ;

[0011] Feeding: 0 to 10 days old, during this stage, the juvenile Octopus sinensis feeds on crab larvae, Artemia nauplii and copepods, Artemia nauplii and copepods are sprayed daily to maintain the Artemia nauplii density at 0.5 to 1 per ml, and the copepod density at 1 to 3 per ml;

[0012] From 10 days to 30 days old or when the number of suckers on the longest arm is less than 20, the larvae in this stage feed on Artemia nauplii and copepods, and the copepods are supplemented to maintain the density at 3-5 / ml.

[0013] After 30 days of age or when the number of suckers on the longest arm reaches 20, the fry enter the bottom-diving period. During this period, live mysis shrimp are put into the water body for the planktonic fry to eat. At the same time, shrimp and shellfish meat pellets that can sink to the bottom of the nursery pond are fed for the bottom-diving fry to eat. The amount of live mysis shrimp put in is 0.1-1kg / mu, and the amount of shrimp and shellfish meat pellets put in is 0.2-1kg / mu. In the early stage of the bottom-diving period, live mysis shrimp are mainly fed, and in the late stage of the bottom-diving period, shrimp and shellfish meat pellets are mainly fed.

[0014] The seedlings are harvested as follows: when the number of the longest arm suckers of the seedlings reaches 40, it indicates that the seedlings have completed the bottoming process and the bottoming seedlings are collected.

[0015] Furthermore, the egg-bearing crab parent is Portunus trituberculatus, Japanese crab or Scylla serrata.

[0016] Furthermore, when the heartbeat of the brooding crab eggs is observed to reach 150 beats / minute, the brooding crab parents are placed in a nursery pond, and the brooding crab parents do not carry pathogens.

[0017] Furthermore, each brooding crab parent is placed in a net bag individually, and the hatched larvae can swim out of the net bag, but the crab parent is always in the net bag.

[0018] The beneficial effects of the present invention compared with the existing technology: At present, the Chinese octopus mainly adopts the factory-based seedling raising technology in the workshop, with a single type of bait, and the bottom of the indoor seedling raising pond is flat, which cannot provide the necessary environmental stimulation for the larvae to lie on the bottom. The Chinese octopus pond ecological seedling raising method provided by the present invention, by placing crab parents in the pond in advance to produce crab larvae, combined with Artemia nauplii and copepods, provides sufficient bait for the early seedlings of Chinese octopus, helping them to successfully survive the "dangerous period" of the first few days after hatching; the copepods that reproduce in large quantities in the pond also provide diversified bait for the seedlings, so that the seedlings can obtain balanced nutrition; nylon mesh and small earthenware jars are laid on the bottom of the pond for the seedlings to hide and lie on the bottom, and at the same time, the environment in the pond is similar to the natural habitat of the Chinese octopus larvae, providing a comfortable living environment and bottom-lying induction conditions for the seedlings, which can effectively promote the growth and bottom-lying of the seedlings. The seedling bottom-lying rate of the seedlings according to the present invention can reach 10.5-11.2%. DETAILED DESCRIPTION

[0019] The technical solution of the present invention is further explained below through examples, but the protection scope of the present invention is not limited in any form by the examples.

[0020] Example 1:

[0021] 1. Pond preparation: On June 11, 2021, a pond was selected in Rizhao, Shandong Province for the cultivation of Octopus sinensis. The pond was a rectangle of 20m×10m with an area of 200m 2 The bottom is gravelly and sandy. During the seedling raising period, the pond water temperature should be 20.1-26.7°C, and the salinity should be 31-33°C. Water quality should comply with GB 11607. Water quality requirements during seedling raising include a temperature of 20-25°C, a salinity of 30-35°C, a pH of 7.8-8.5, and dissolved oxygen ≥5 mg / L. The pond was disinfected and exposed to sunlight for 20 days before use. Ten days before use, 100 kg / mu of quicklime was evenly sprayed throughout the pond for disinfection.

[0022] 2. Cultivation of Bait Organisms: Install a bottom aerator in the pond and place a large amount of nylon mesh and small earthenware pots to shelter the larvae. Fill the pond with water to a depth of 1.5 m and inoculate with Chlorella. Apply 10 ppm nitrogen fertilizer daily until the water turns dark green, then inoculate with rotifers.

[0023] When the density of rotifers in the pond reaches 8-10 / ml, place the strong and vigorous Japanese crabs with eggs in the pond. Observe the heartbeat of the eggs before placing them in the pond. When it reaches 150 beats / minute, place the Japanese crabs in the pond. The Japanese crabs are first bathed in a 20ppm formaldehyde solution for 0.5 hours. Each individual is then placed in a nylon mesh bag. The mesh bag containing the crabs with eggs is placed in the pond. On average, 1000 crabs are placed in the pond every 30 minutes. 3 One was released. Four days later, crab larvae began to hatch in the pond. During this period, nitrogen fertilizer was applied to maintain the concentration of Chlorella in the pond, keeping the water dark green and providing food for the hatched crab larvae.

[0024] 3. Seedling distribution: 8 days after the Japanese crab broodstock is added, when the density of crab zoeae in the pond reaches 0.3 / ml, the crab broodstock is removed from the pond and the Chinese octopus seedlings are distributed. The newly hatched Chinese octopus juveniles are evenly distributed in the pond at a density of 1000 / m 3 .

[0025] 4. Feeding: From 0 to 10 days old, sprinkle Artemia nauplii and copepods every day to maintain the Artemia nauplii density at 0.5-1 / ml and copepods at 1-3 / ml. From 0 to 10 days old, the larvae can feed on crab larvae, Artemia nauplii and copepods. Sprinkle Artemia nauplii and copepods every day. Purchase Artemia eggs and Artemia nauplii hatched at 26°C. After 6 hours of nutritional enrichment with 0.07g / L Schizochytrium, add them to the pond. Maintain the Artemia nauplii density at 0.5-1 / ml. Purchase copepods for feeding, and maintain the density at 1-3 / ml. The crab larvae in the pond provide rich nutrients such as DHA and EPA for the early seedlings of Chinese octopus, which can ensure a high survival rate and growth rate of the larvae.

[0026] From 10 days to 31 days old, the larvae can feed on Artemia nauplii and copepods. At this time, the pond has undergone early cultivation and copepods have reproduced in large numbers. According to the number of copepods in the pond, a small amount of copepods is added to maintain the density at 3 to 5 per ml.

[0027] After 32 days of age, most individuals have 20 suckers on their longest arms, marking the beginning of a bottom-dwelling period. This period can last one to two months, with the juveniles repeatedly floating and dormant until completely dormant. During this period, live mysis shrimp are introduced to the water for the planktonic juveniles, along with bottom-dwelling shrimp and shellfish pellets. Initially, the primary feed is purchased live mysis shrimp at a daily rate of 0.5 kg, gradually decreasing to 0.1 kg / day as the juveniles develop until harvest. Shrimp and shellfish pellets are initially fed in small quantities, at a rate of 0.2 kg / day, increasing to 0.6 kg / day as the juveniles develop. Fresh shrimp (L. vannamei) and scallop (Ctenops farreri) are used as shellfish.

[0028] During the seedling raising process, beneficial microbial agents are sprayed throughout the pond every three days to regulate the water quality.

[0029] At 86 days of age, it was found that the longest arm sucker number of most seedlings reached 40, and the seedlings were harvested. A total of 31,529 seedlings were collected, with a harvest rate of 10.5%.

[0030] Example 2:

[0031] 1. Pond preparation: On May 16, 2021, Octopus sinensis seedlings were raised in a pond in Xiapu, Fujian Province. The selected pond was a 15m×15m square with an area of 225m 2 The pond has a sandy and gravel bottom. During the seedling raising period, the water temperature in the pond is 20.5-27.6°C, and the salinity is 32-34. The pond has been exposed to the sun and disinfected before use.

[0032] 2. Cultivation of Bait Organisms: A microporous aerator was installed at the bottom of the pond, along with numerous nylon mesh sheets and small earthenware jars. Water was added to a depth of 1.5 m3 and inoculated with Chlorella. A 10 ppm nitrogen fertilizer was applied daily until the water turned dark green, followed by inoculation with rotifers.

[0033] When the density of rotifers in the pond reaches 8-10 / ml, put the swimming crabs in good condition. Select the Japanese crabs with a heartbeat frequency of 150 times / minute, bathe them in 20ppm formaldehyde solution for 0.5 hours, put them into their own nylon mesh bags, put the mesh bags containing the swimming crabs into the pond, and place them every 50m on average. 3 One was released. Three days later, zoeae were observed in the pond. Nitrogen fertilizer was applied to maintain the pond water's dark green color.

[0034] 3. Seedlings: 6 days after the introduction of the swimming crab parent crabs, when the density of the crab zoeae in the pond reaches 0.5 / ml, remove the parent crabs. Evenly distribute the newly hatched juveniles of Octopus sinensis in the pond at a seedling density of 1000 / m 3 .

[0035] 4. Feeding: From 0 to 10 days old, sprinkle Artemia nauplii and copepods every day. The method of obtaining Artemia nauplii is the same as that in Example 1. The density of Artemia nauplii in the pond is maintained at 0.5 to 1 / ml; purchase copepods for feeding, and the density is maintained at 1 to 3 / ml.

[0036] From 10 days to 28 days of age, the copepod density in the pond was always maintained above 3 / ml, and no new copepods were added.

[0037] After 29 days of age, when most individuals reached 20 suckers on their longest arms, they began feeding live mysis shrimp and shrimp and shellfish pellets. In the early stages, they primarily fed purchased live mysis shrimp at a daily rate of 0.6 kg, gradually decreasing to 0.2 kg / day in the middle and later stages. Shrimp and shellfish pellets were fed in small amounts at a daily rate of 0.2 kg in the early stages, gradually increasing to 0.8 kg / day in the middle and later stages. The shrimp used were fresh Litopenaeus vannamei, and the shellfish were Crassostrea gigas.

[0038] During the seedling raising process, beneficial microbial agents are sprayed throughout the pond every three days to regulate the water quality.

[0039] At 75 days of age, it was found that the longest arm sucker number of most seedlings reached 40, and the seedlings were harvested. A total of 37,723 seedlings were collected, with a harvest rate of 11.2%.

Claims

1. A method for cultivating Octopus sinensis seedlings in ponds, characterized in that: The method comprises the steps of preparing a nursery pond, cultivating bait organisms, arranging seedlings, feeding bait and harvesting seedlings; Preparation of the nursery pond: the water temperature of the nursery pond is 20-28°C, the salinity is 31-35, the bottom of the pond is gravel, and it is exposed to the sun for 10-15 days before use; 7-10 days before stocking, add 20-30cm of water and disinfect it; Cultivation of the bait organisms: a bottom microporous aerator is arranged in the pond, and a nylon mesh and a small earthenware pot are placed at the bottom of the pond to shelter the larvae; water is added to a depth of 1.5 to 2 meters, and chlorella is inoculated. Nitrogen fertilizer is sprayed every day until the pond water turns dark green, and then rotifers are inoculated; When the density of rotifers in the pond reaches 8-10 / ml, put the strong and vigorous egg-bearing crabs into the nursery pond; on average, every 30-50m 3 Release one brooding crab parent and maintain the concentration of Chlorella and rotifers in the nursery pond after the crab zoeae hatch to provide food for the hatched crab zoeae. The seedling distribution method is as follows: when the density of crab zoeae in the nursery pond reaches 0.2-0.5 / ml, the crab parents are taken out from the nursery pond and the Chinese octopus seedlings are distributed; the hatched Chinese octopus larvae are evenly distributed in the nursery pond, and the number is controlled at 1000-2000 / m 3 ; Feeding the bait: at 0 to 10 days old, the juvenile Octopus sinensis feeds on crab zoeae, Artemia nauplii and copepods. Artemia nauplii and copepods are sprayed daily to maintain the Artemia nauplii density at 0.5 to 1 per ml and the copepod density at 1 to 3 per ml. From 10 days to 30 days old or when the number of suckers on the longest arm is less than 20, the larvae in this stage feed on Artemia nauplii and copepods, and the copepods are supplemented to maintain the density at 3-5 / ml. After 30 days of age or when the number of suckers on the longest arm reaches 20, the fry enter the bottom-diving period. During this period, live mysis shrimp are put into the water body for the planktonic fry to eat. At the same time, shrimp and shellfish meat pellets that can sink to the bottom of the nursery pond are fed for the bottom-diving fry to eat. The amount of live mysis shrimp put in is 0.1-1kg / mu, and the amount of shrimp and shellfish meat pellets put in is 0.2-1kg / mu. In the early stage of the bottom-diving period, live mysis shrimp are mainly fed, and in the late stage of the bottom-diving period, shrimp and shellfish meat pellets are mainly fed. The seedlings are harvested as follows: when the number of the longest arm suckers of the seedlings reaches 40, it indicates that the seedlings have completed the bottoming process and the bottoming seedlings are collected.

2. The method for cultivating Octopus sinensis seedlings in ponds according to claim 1, wherein: The egg-bearing crab parent is swimming crab trituberculate, Japanese crab or mud crab.

3. The method for cultivating Octopus sinensis seedlings in ponds according to claim 1, wherein: When the heartbeat of the brooding crab eggs is observed to reach 150 beats / minute, the brooding crab parents are placed in the nursery pond. The brooding crab parents do not carry pathogens.

4. The method for cultivating Octopus sinensis seedlings in ponds according to claim 1, wherein: Each egg-bearing crab parent is placed in a net bag separately. The hatched larvae can swim out of the net bag, but the crab parent remains in the net bag at all times.