Mandarin fish parent fish rearing and fry opening rearing method suitable for northern areas

Abstract

The invention discloses a parent mandarin fish rearing and fry opening rearing method suitable for northern areas. The parent breeding method in the method comprises the steps that from the beginning of February, high-quality mandarin fish parents are selected, prenatal parents are bred in a cement pond in a greenhouse, carps are used as bait fishes, breeding is conducted to the middle ten days of April, and male fishes and female fishes with good gonad development are selected for spawning induction. The fry opening breeding method comprises the steps that mandarin fish fries swim flatly three days after going out of the film, loach water spots are fed after the mandarin fish fries swim flatly for 60-75 h, and carp fries with the body length smaller than 60% of the mandarin fish fries are fed 7 days after feeding. According to the method, water temperature fluctuation can be avoided through parent fish breeding in a greenhouse cement pond, the stability of bait supply in northern areas can be guaranteed by taking carps as bait fishes, and more than 90% of mandarin fish parent gonads are promoted to develop to the V period. Loach water spots are selected as initial feed for the mandarin fish fries, and the initial feed is matched with spawning induction, so that the method is more suitable for climate of northern areas, feed supply can be guaranteed, and the survival rate of the mandarin fish fries in the initial stage can reach 80%.

Description

Technical Field

[0001] The invention relates to the technical field of mandarin fish breeding, in particular to a mandarin fish broodstock breeding and seedling starter breeding method suitable for northern regions. Background Art

[0002] Mandarin fish, known for its tender texture, lack of intramuscular spines, and rich amino acids, has high market value and aquaculture potential. In recent years, with the decline of wild mandarin fish populations, mandarin fish aquaculture has rapidly emerged, particularly in water-rich regions such as the Yangtze and Pearl River basins, where it has rapidly developed and become an industrialized industry.

[0003] In contrast, mandarin fish farming in northern China is still in its exploratory stages. For example, northern China currently uses large-scale production methods adapted for southern China. During parent stock rearing, dace, silver carp, and bighead carp are primarily used as forage fish. However, because these forage fish have a reproductive cycle tailored to the southern climate (relying on open ponds with stable water temperatures (>22°C), dissolved oxygen ≥5 mg / L, and a pH of 7.5-8.0), they have poor cold tolerance and are unable to adapt to the low temperatures and fluctuating water temperatures of northern China, resulting in an unstable supply of forage fish. In addition, the winters in northern China are long and cold, and the water temperature is often lower than the suitable temperature for the growth of mandarin fish. This slows down the metabolism of the broodstock, resulting in delayed gonadal development of the broodstock and the inability to guarantee the quality of the eggs. When the spawning period arrives, the proportion of broodstock whose gonads have developed to stage V is only 60-80%, and the egg production of a single mandarin fish broodstock is only 15,000 to 35,000 eggs, with a fertilization rate of ≤60%, which affects the breeding cycle and breeding effect of the mandarin fish, and cannot achieve the same breeding effect as the mandarin fish broodstock in the south.

[0004] Furthermore, during the current seedling breeding period, the use of dace and croaker as bait for mandarin fish fry also presents an unstable supply of bait fish. Furthermore, the fry breeding process is not synchronized with the induction of spawning by the bait fish, resulting in low feeding efficiency and uneven fry growth. Furthermore, the large temperature swings in the spring in northern China lead to a high incidence of parasitic diseases, which causes a strong stress response in the mandarin fish fry. The membrane rupture rate is only 80-90%, the loss rate before breeding reaches 35%, and the survival rate during the breeding period is ≤50%. This overall survival rate is low, and the breeding costs and risks are high.

[0005] Therefore, the large-scale production of mandarin fish aquaculture in northern China still faces the following urgent problems: (1) delayed development of parent fish gonads; (2) low survival rate of seedlings; and (3) lack of supporting technology for bait fish, which is not conducive to large-scale production of mandarin fish aquaculture in northern China.

[0006] Therefore, the existing methods for broodstock and seedling cultivation of mandarin fish are clearly still not adapted to the northern environment and are in urgent need of further improvement. How to create a new method for broodstock and seedling cultivation of mandarin fish adapted to the northern region, improving it by focusing on three key technologies: targeted parent selection, precise environmental control, and efficient bait fish matching, significantly improving the breeding efficiency and seedling quality of mandarin fish in the north, and promoting the prosperity and development of mandarin fish aquaculture in the north, has become a goal that the industry urgently needs to improve. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to provide a method for breeding broodstock and seedlings of mandarin fish that is suitable for the northern region, so that the method can be improved from three key technologies: directional selection of parents, precise control of the environment, and efficient matching of bait fish, thereby significantly improving the breeding efficiency and seedling quality of mandarin fish in the north, promoting the prosperous development of mandarin fish farming in the northern region, and overcoming the problem that the existing methods for breeding broodstock and seedlings of mandarin fish cannot be adapted to the northern region.

[0008] In order to solve the above technical problems, the present invention provides a method for breeding broodstock and fry of mandarin fish suitable for northern regions, including a broodstock breeding method and a fry breeding method.

[0009] The parent rearing method is as follows: Starting in early February in northern China, select high-quality breeding ponds or screened wild populations of mandarin fish as mandarin fish parents, carry out pre-spawning parent rearing in greenhouse cement pools, use carp as bait fish, the bait fish size is 38 fish / kg, feed twice a day, and the ratio of bait fish to mandarin fish is 5:1. Pre-spawn rearing is carried out until mid-April. Males aged 2+ and over, and females aged 3+ and over, weighing more than 1500g, with females having a swollen, soft, and elastic abdomen and a clear ovarian outline, and males with a rosy and prominent genital pore, good development, strong physique, no disease, injury, or deformity, are selected. They are then transferred to the spawning cement pool at a male-to-female ratio of 1:1-2 to prepare for induced spawning.

[0010] The method for seedling cultivation is as follows: three days after the mandarin fish fry hatch, they swim horizontally in the hatching bucket. After swimming horizontally for 60 to 75 hours, they are fed with 3mm loach water splashes that have just swam horizontally, so that the mandarin fish fry can start to eat. This feeding is carried out for 3 days, 3 times a day; continue to feed 3 to 6mm loach, feed for 4 days, 3 times a day; then feed carp fry that is less than 60% of the mandarin fish fry in length. When the mandarin fish fry grow to 0.8 cm, they are stocked into cement pools at a density of 30,000 per cubic meter of water. When they grow to 1.5 to 2.0 cm, they are cultivated in separate pools.

[0011] Further improvement, in the parent cultivation method, the area of the greenhouse cement pool is 25m 2, water depth 0.9m, keep the water quality fresh during the cultivation period, maintain dissolved oxygen at more than 6.0mg / L, pH value 8.2, water temperature should be 24~27℃, transparency is above 30cm, ammonia nitrogen concentration is less than 0.2mg / L, nitrite is less than 0.1mg / L, and sewage is regularly discharged and new water is replaced.

[0012] As a further improvement, the parent breeding method also includes the steps of regularly observing the swimming, feeding, and body color changes of the mandarin fish parents every day, promptly detecting diseases and stress problems, and promptly dealing with them.

[0013] As a further improvement, the seedling cultivation method further includes the step of inducing the spawning of loaches with the seedlings, and the step of inducing the spawning of loaches with the seedlings is as follows:

[0014] Select loach parents that are one winter old, with a body length of more than 15 cm, a full abdomen, thick back muscles, strong activity, and no disease or deformity; and start inducing spawning of the loach parents three days after the mandarin fish fry hatch out of the membrane, so that the time when their fertilized eggs hatch out of the membrane is synchronized with the time when the mandarin fish fry start to eat, so as to meet the food needs of the mandarin fish fry for 1 to 7 days.

[0015] As a further improvement, the first feeding when the mandarin fish fry start to eat is to feed 70,000 to 80,000 3mm loaches that have just swum horizontally for every 10,000 mandarin fish fry, and the subsequent feeding is to feed 30,000 to 40,000 loaches for every 10,000 mandarin fish fry.

[0016] Further improvement, the seedling opening cultivation method further includes a carp supporting spawning step, and the carp supporting spawning step is:

[0017] When the mandarin fish fry start to eat, the carp parents are induced to give birth, so that when the mandarin fish fry start to eat the carp fry, the carp fry are less than 60% of the mandarin fish fry's body length;

[0018] The carp parents selected should be male fish aged 2+ years and above, female fish aged 3+ years and above, weighing more than 1500g, with a well-proportioned body, intact scales, and no external injuries or parasites.

[0019] Further improvement: when the mandarin fish fry start to eat carp fry, the daily feeding amount of the carp fry is 20% of the total body weight of the mandarin fish fry, which is fed in 3 times.

[0020] Further improvement: in the seedling open cultivation method, the water quality in the hatching bucket is: pH 7.5~8.5, water temperature 24~27℃, ammonia nitrogen concentration less than 0.2mg / L, nitrite less than 0.1mg / L, and dissolved oxygen greater than 6.0mg / L.

[0021] As a further improvement, before feeding the bait fish, the bait fish is disinfected by soaking in 3-5% salt for 5-10 minutes or soaking in 1% povidone iodine for 10-15 minutes.

[0022] Further improvements have been made to the parent breeding method, which can ensure that the proportion of gonadal development of the mandarin fish parents to stage V is higher than 90%, and the average egg production per tail of the mandarin fish parents reaches 36,000 to 46,000 eggs per tail, and the fertilization rate of the mandarin fish parents reaches 70%;

[0023] The seed opening cultivation method can ensure that the membrane breaking rate of mandarin fish seedlings is ≥95%, and the loss rate from membrane breaking to opening is ≤15%, and the survival rate of mandarin fish seedlings during the opening period can reach 80%.

[0024] After adopting such a design, the present invention has at least the following advantages:

[0025] The method for breeding broodstock and fry opening of mandarin fish of the present invention is targeted at the characteristics of northern regions. A greenhouse cement pool is selected for pre-spawn breeding of the broodstock to avoid water temperature fluctuations. In addition, low-temperature-resistant and highly adaptable carp is selected as an alternative bait fish to ensure the stability of bait supply in the northern region. In addition, the parent breeding is started in early February to ensure that more than 90% of the mandarin fish parents have developed gonads to the V stage by mid-April, thereby promoting the single-tail spawning amount and fertilization rate, meeting the development needs of the mandarin fish artificial breeding industry in the northern region, and promoting the prosperous development of the mandarin fish breeding industry in the northern region.

[0026] By selecting loach water splashes as the starter bait for mandarin fish fry, and using the induction-induced spawning of loach and carp as the starter bait, the method is not only more suitable for the climate in the northern region, but also breaks through the resource limitations of the northern region's use of streamlined fish such as dace and croaker, ensuring the supply of bait for mandarin fish fry. This method can promote the survival rate of mandarin fish fry in the starter period to 80%, breaking through the technical bottleneck of large-scale artificial breeding of mandarin fish in the northern region, and promoting the healthy and sustainable development of mandarin fish farming in the northern region. DETAILED DESCRIPTION

[0027] Due to the uneven distribution of water resources in northern China, long, cold winters, and relatively low water temperatures, large-scale artificial propagation methods for mandarin fish (Siniperca chuatsi) differ significantly from those in southern China. To implement large-scale artificial propagation of mandarin fish in northern China, this application fully considers the climatic characteristics of the region, such as the slow spring temperature rise and large diurnal temperature differences, as well as the characteristics of bait resources. It explores key technologies for mandarin fish parent breeding and seedling cultivation, aiming to overcome the technical bottlenecks of large-scale artificial propagation of mandarin fish in northern China, promote the healthy and sustainable development of the mandarin fish aquaculture industry in northern China, ensure the survival rate of mandarin fish seedlings, and ensure that the bred seedlings are uniform in size and strong in vitality. Specific embodiments are as follows.

[0028] This embodiment is suitable for the method of breeding broodstock and fry cultivation of mandarin fish in northern regions, including a broodstock breeding method and a fry cultivation method.

[0029] The parent breeding method is: starting from early February in the northern region, select high-quality breeding ponds or screened wild populations of mandarin fish as mandarin fish parents, and carry out pre-production parent breeding in greenhouse cement pools. The area of the greenhouse cement pool is 25m 2 , water depth 0.9m, keep the water quality fresh during the cultivation period, maintain dissolved oxygen at more than 6.0mg / L, pH value 8.2, water temperature should be 24~27℃, transparency is above 30cm, ammonia nitrogen concentration is less than 0.2mg / L, nitrite is less than 0.1mg / L, regularly drain sewage and replace new water to ensure the normal operation of the water treatment system.

[0030] Carp are used as a substitute for bait fish, with a bait fish size of 38 per kg, and are fed twice a day, with a bait fish to mandarin fish ratio of 5:1. Of course, in the event of sudden weather changes or rainy days, feeding should be reduced as appropriate.

[0031] Use the above method for pre-spawning rearing. During the rearing period, regularly observe the swimming, feeding, and body color changes of the mandarin fish parents every day, such as whether they lurk at the bottom of the water during the day, whether their bodies are stretched, whether they feed actively and stably when fed, and whether their body color is bright and shiny, with clear markings. If they swim away from the group, have abnormal feeding, or change their body color, it is necessary to check for diseases, stress, and other problems in combination with water quality and other factors and deal with them in a timely manner.

[0032] Pre-spawning cultivation is carried out until early April. Male fish aged 2+ and above and female fish aged 3+ and above, weighing more than 1500g, with a swollen, soft and elastic abdomen of female fish and obvious ovarian outline, and male fish with rosy and prominent genital pores, good development, strong physique, no disease, injury or deformity, are selected. They are transferred to the spawning cement pool at a male-to-female ratio of 1:1~2 to prepare for induced spawning.

[0033] The above-mentioned method for broodstock cultivation of mandarin fish can achieve a gonadal development rate of more than 90% in mandarin fish parents reaching stage V, an average egg production of 36,000 to 46,000 eggs per tail, and a fertilization rate of 70%. This method can adapt mandarin fish broodstock to northern China, achieving good breeding results and achieving the same broodstock cultivation results as mandarin fish in southern China.

[0034] The seedling opening cultivation method in this embodiment is as follows: three days after the mandarin fish fry emerge from the membrane, they swim horizontally in the hatching bucket, and are fed with 3mm loach water spray that has just swam horizontally for 60-75 hours to encourage the mandarin fish fry to start eating. This feeding is carried out for 3 days, 3 times a day; 3-6mm loach is continued to be fed for 4 days, 3 times a day; thereafter, carp fry with a body length less than 60% of the mandarin fish fry are fed. When the mandarin fish fry grow to 0.8 cm, they are stocked into cement ponds at a density of 30,000 per cubic meter of water. When they grow to 1.5-2.0 cm, they are cultured in separate ponds.

[0035] In order to ensure the accurate supply of bait fish, the seedling cultivation method also includes the step of induced spawning of loach with the seedlings, and the step of induced spawning of loach with the seedlings is: selecting loach parents that are one winter old, with a body length of more than 15 cm, a full abdomen, thick back muscles, strong activity, and no disease or deformity; and starting to induce spawning of loach parents three days after the mandarin fish seedlings hatch, so that the hatching time of their fertilized eggs is synchronized with the time when the mandarin fish seedlings start to eat, so as to meet the bait needs of the mandarin fish seedlings for 1-7 days.

[0036] Furthermore, the first feeding of mandarin fish fry, when they first start feeding, is to be fed 70,000 to 80,000 3mm loaches per 10,000 fry. The subsequent feedings are to be fed 30,000 to 40,000 loaches per 10,000 fry. This is because mandarin fish fry lack swimming ability when they first start feeding, so high-density feeding facilitates their feeding and improves their survival rate.

[0037] More preferably, the fry start-up cultivation method further includes a carp spawning step. The carp spawning step comprises: initiating spawning of the carp parent when the mandarin fish fry start feeding, such that the carp fry are less than 60% of their body length when the mandarin fish fry start feeding on the carp fry. Furthermore, when the mandarin fish fry begin feeding on the carp fry, the carp fry are fed a daily amount of 20% of their total body weight, divided into three feedings.

[0038] Among them, the selection of carp parents in the carp induced spawning steps is: male fish are over 2 years old, female fish are over 3 years old, individual weight is over 1500g, body shape is symmetrical, scales are intact, and there is no external injury or parasites.

[0039] In addition, the water quality in the hatching bucket in the seedling open cultivation method is: pH 7.5-8.5, water temperature 24-27°C, ammonia nitrogen concentration less than 0.2 mg / L, nitrite less than 0.1 mg / L, and dissolved oxygen greater than 6.0 mg / L.

[0040] Before feeding the bait fish in the method for breeding broodstock and fry opening of mandarin fish in this embodiment, the bait fish are all soaked in 3-5% salt for 5-10 minutes or in 1% povidone-iodine for 10-15 minutes for disinfection.

[0041] The above-mentioned method for seedling opening cultivation can achieve a membrane-breaking rate of ≥95% for mandarin fish fry, with a loss rate of ≤15% from membrane breaking to opening, and an 80% survival rate for mandarin fish fry during the opening period. This method is further adapted to meet the needs of seedling opening cultivation in northern China, significantly improving the current survival rate of mandarin fish fry during opening cultivation, and producing uniform and vigorous seedlings.

[0042] The present invention selects cold-resistant and more adaptable carp as an alternative bait fish for parent fish cultivation, thereby ensuring the stability of bait supply during parent fish cultivation and conforming to the environmental characteristics of northern waters. The present invention also satisfies the feeding needs of mandarin fish fry by selecting cold-resistant and fast-breeding loach fry. After feeding for a week, the fry can feed on the carp fry that has just swum horizontally, thereby better adapting to the characteristics of the northern region and meeting the opening cultivation of mandarin fish fry in the northern region. The present invention also synchronizes the spawning time of bait fish and mandarin fish fry through the supporting management of bait, resulting in sufficient supply of loach fry and carp fry bait and palatable specifications when the mandarin fish fry start to feed, meeting the principle of "palatable specifications, rather small than large", greatly improving the survival rate of fry, meeting the needs of mandarin fish broodstock cultivation and seedling opening cultivation in the northern region, and promoting the prosperous development of mandarin fish breeding industry in the northern region.

[0043] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Those skilled in the art can make some simple modifications, equivalent changes or modifications based on the technical content disclosed above, which all fall within the scope of protection of the present invention.

Claims

1. A method for breeding broodstock and seedlings of mandarin fish suitable for northern regions, characterized in that: Including parent cultivation method and seedling opening cultivation method, The parent rearing method is as follows: Starting in early February in northern China, select high-quality breeding ponds or screened wild populations of mandarin fish as mandarin fish parents, carry out pre-spawning parent rearing in greenhouse cement pools, use carp as bait fish, the bait fish size is 38 fish / kg, feed twice a day, and the ratio of bait fish to mandarin fish is 5:

1. Pre-spawn rearing is carried out until mid-April. Males aged 2+ and over, and females aged 3+ and over, weighing more than 1500g, with females having a swollen, soft, and elastic abdomen and a clear ovarian outline, and males with a rosy and prominent genital pore, good development, strong physique, no disease, injury, or deformity, are selected. They are then transferred to the spawning cement pool at a male-to-female ratio of 1:1-2 to prepare for induced spawning. The method for seedling cultivation is as follows: three days after the mandarin fish fry hatch, they swim horizontally in the hatching bucket. After swimming horizontally for 60 to 75 hours, they are fed with 3mm loach water splashes that have just swam horizontally, so that the mandarin fish fry can start to eat. This feeding is carried out for 3 days, 3 times a day; continue to feed 3 to 6mm loach, feed for 4 days, 3 times a day; then feed carp fry that is less than 60% of the mandarin fish fry in length. When the mandarin fish fry grow to 0.8 cm, they are stocked into cement pools at a density of 30,000 per cubic meter of water. When they grow to 1.5 to 2.0 cm, they are cultivated in separate pools.

2. The method for breeding broodstock and seedlings of mandarin fish adapted to northern regions according to claim 1, characterized in that: In the parent cultivation method, the greenhouse cement pool area is 25m 2 , water depth 0.9m, keep the water quality fresh during the cultivation period, maintain dissolved oxygen at more than 6.0mg / L, pH value 8.2, water temperature should be 24~27℃, transparency is above 30cm, ammonia nitrogen concentration is less than 0.2mg / L, nitrite is less than 0.1mg / L, and sewage is regularly discharged and new water is replaced.

3. The method for breeding broodstock and seedlings of mandarin fish adapted to northern regions according to claim 2, wherein: The parent breeding method also includes the steps of regularly observing the swimming, feeding, and body color changes of the mandarin fish parents every day, timely discovering diseases and stress problems, and promptly dealing with them.

4. The method for breeding broodstock and seedlings of mandarin fish adapted to northern regions according to claim 1, wherein: The seedling opening cultivation method further includes the step of accelerating the spawning of loaches with the seedling opening, and the step of accelerating the spawning of loaches with the seedling opening is as follows: Select loach parents that are one winter old, with a body length of more than 15 cm, a full abdomen, thick back muscles, strong activity, and no disease or deformity; and start inducing spawning of the loach parents three days after the mandarin fish fry hatch out of the membrane, so that the time when their fertilized eggs hatch out of the membrane is synchronized with the time when the mandarin fish fry start to eat, so as to meet the food needs of the mandarin fish fry for 1 to 7 days.

5. The method for breeding broodstock and seedlings of mandarin fish adapted to northern regions according to claim 4, characterized in that: The first feeding when the mandarin fish fry start to eat is to feed 70,000 to 80,000 3mm loaches that have just swum horizontally for every 10,000 mandarin fish fry. The subsequent feeding is to feed 30,000 to 40,000 loaches for every 10,000 mandarin fish fry.

6. The method for breeding broodstock and seedlings of mandarin fish adapted to northern regions according to claim 5, characterized in that: The seedling opening cultivation method further includes a carp spawning-inducing step, and the carp spawning-inducing step is as follows: When the mandarin fish fry start to feed, the carp parents are induced to spawn, so that the carp fry grow less than 60% of the mandarin fish fry's body length during the period when the mandarin fish fry start to feed the carp fry; The carp parents selected should be male fish aged 2+ years and female fish aged 3+ years and above, weighing more than 1500g, with a well-proportioned body, intact scales, and no external injuries or parasites.

7. The method for breeding broodstock and seedlings of mandarin fish adapted to northern regions according to claim 6, characterized in that: When the mandarin fish fry start to feed on the carp fry, the daily feeding amount of the carp fry is 20% of the total body weight of the mandarin fish fry, which is fed in 3 times.

8. The method for breeding broodstock and seedlings of mandarin fish adapted to northern regions according to claim 4, characterized in that: In the seedling opening cultivation method, the water quality in the hatching bucket is as follows: pH is 7.5-8.5, water temperature is 24-27°C, ammonia nitrogen concentration is less than 0.2 mg / L, nitrite is less than 0.1 mg / L, and dissolved oxygen is greater than 6.0 mg / L.

9. The method for breeding broodstock and seedlings of mandarin fish adapted to northern regions according to claim 1, characterized in that: Before feeding the bait fish, the bait fish is disinfected by soaking in 3-5% salt for 5-10 minutes or soaking in 1% povidone-iodine for 10-15 minutes.

10. The method for breeding broodstock and fry of mandarin fish adapted to northern regions according to claim 1, characterized in that: The parent breeding method can ensure that the proportion of gonadal development of mandarin fish parents to stage V is higher than 90%, and the average egg production per tail of mandarin fish parents reaches 36,000 to 46,000 eggs / tail, and the fertilization rate of mandarin fish parents reaches 70%; The seedling opening cultivation method can ensure that the membrane breaking rate of the mandarin fish seedlings is ≥95%, and the loss rate from membrane breaking to opening is ≤15%, and the survival rate of the mandarin fish seedlings during the opening period can reach 80%.