A method for farming one crab and two shrimp
By using a crab-two-shrimp farming method, combined with seasonal and off-peak farming, the problems of large crab farming area, high water quality requirements, and unstable yield have been solved, achieving high and stable yields of crabs, crayfish, and freshwater shrimp, and improving economic benefits.
Patent Information
- Application Number
- CN202310627387.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2023-05-31
- Publication Date
- 2026-01-30
- Estimated Expiration
- 2043-05-31
AI Technical Summary
Crab farming requires a large area, has high requirements for water quality, is easily affected by abnormal weather, has unstable output, and does not have a prominent market price. Furthermore, polyculture systems have a negative impact on crab production.
The farming method of "one crab and two shrimp" is adopted, which includes releasing river crabs in February and March, crayfish in March and April, and freshwater shrimp in June. By seasonal and staggered farming, the stocking quantity and harvest time are reasonably controlled. The different feeding methods of shrimp and crabs are utilized to reduce interspecies competition and optimize the farming environment.
It improves the growth status of river crabs, crayfish, and freshwater shrimp, makes full use of aquaculture resources, reduces market risks, enhances overall economic benefits, meets different consumer demands, and significantly increases shrimp and crab production and output value.
Smart Images
Figure CN116602249B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of aquaculture technology, specifically relating to a method for farming one crab and two shrimp. Background Technology
[0002] Currently, crab farming often requires a large area and involves strict conditions, including high water quality requirements. Crab farming is also susceptible to abnormal weather, resulting in unstable yields and inconsistent market prices. Therefore, crab farming faces significant risks. In polyculture systems, the conditions of the mixed culture often have adverse effects on crabs, significantly impacting yields. Therefore, developing a crab farming method that can increase the yields of other aquatic products in the polyculture system while ensuring crab production is one of the most pressing technical problems to be solved in the field of crab farming. Summary of the Invention
[0003] In view of the shortcomings of the existing technology, the purpose of this invention is to provide a method for farming crabs and two shrimps, which can fully utilize aquaculture resources, provide good farming conditions for crabs, ensure the output value of crabs, and increase the income of the aquaculture system.
[0004] The objective of this invention is achieved through the following technical solution:
[0005] This invention provides a method for farming one crab and two shrimp, comprising the following steps:
[0006] River crabs are released in February and March, crayfish in March and April, and freshwater shrimp in June for mixed shrimp and crab farming.
[0007] Preferably, when releasing river crabs, the stocking size is 60-160 crabs / kg, and the stocking density is 700-1200 crabs / mu; when releasing crayfish, the stocking size is 400-500 crayfish / kg, and the stocking density is 1500-2000 crayfish / mu; when releasing freshwater shrimp, the shrimp size is 4-5g / shrimp, and the stocking density is 40-60 shrimp / mu.
[0008] Preferably, the prawn is a berried prawn; the prawn species include Taihu No. 2 and / or Taihu No. 3.
[0009] Ideally, 70% to 90% of the crayfish should be harvested during the third molting period of the river crabs, and the remaining crayfish should be harvested in September and later.
[0010] Preferably, the harvesting time for crayfish in September and later includes any period from September to November or during the Spring Festival, or both of these periods.
[0011] Preferably, crayfish are harvested when the breeding period is ≥35 days; the weight of each crayfish at harvest is ≥20g.
[0012] Ideally, freshwater shrimp should be harvested after 70-80 days of cultivation.
[0013] Preferably, the crabs are fed during the breeding period; the daily feed amount is 8% to 12% of the crab's body weight.
[0014] This invention provides the application of the aquaculture method described in the above technical solution in increasing shrimp and crab production.
[0015] The beneficial effects of this invention are:
[0016] This invention provides a method for raising crabs and two types of shrimp, which includes: releasing river crabs in February to March, releasing crayfish in March to April, and releasing freshwater shrimp in June to carry out mixed shrimp and crab farming.
[0017] In the shrimp and crab co-culture method provided by this invention, the first, second, and third molting periods of river crabs are from March to May each year. During these periods, the river crabs are relatively small, and there is a large amount of spare space in the aquaculture system. Co-culturing river crabs and crayfish in the aquaculture system during this period can make full use of the aquaculture system, effectively avoid interspecies competition between river crabs and crayfish, and ensure that both crayfish and river crabs are in a good growth state.
[0018] The yield of freshwater prawn larvae is low in the first half of the year, and the growth of the larvae is uneven. In the crab-two-prawn farming method provided by this invention, freshwater prawns are released in June, after the crabs have molted three times. In July, crayfish begin to burrow. The larvae hatched by the released berried freshwater prawns have basically grown into small freshwater prawn larvae by July. This allows both crayfish and freshwater prawn larvae to make full use of the entire farming system and reduces interspecies competition.
[0019] Meanwhile, shrimp and crabs have different feeding methods. Crayfish and prawns can utilize the leftover feed from river crabs, thereby maximizing feed utilization, maintaining good aquaculture water quality, and improving aquaculture environment conditions.
[0020] In summary, the crab-two-shrimp farming method provided by this invention allows for the stocking of crayfish and freshwater shrimp in existing crab ponds. This enables the ponds to produce not only crabs grown throughout the year, but also crayfish in the first half of the year and freshwater shrimp in the second half, fully utilizing the existing aquaculture system. The crab-two-shrimp farming system employs seasonal, relay, and staggered farming methods, ensuring that crayfish, freshwater shrimp, and crabs are all in optimal growth conditions, thereby improving the overall economic efficiency of the farming system. This crab-two-shrimp farming method contributes to increasing fishermen's income and rural revitalization. The seasonal and staggered market availability of shrimp and crabs meets diverse consumer demands, and the harvest of crayfish can be delayed when the market is unfavorable, significantly reducing market risk.
[0021] Furthermore, in the crab-two-shrimp farming method provided by this invention, by rationally controlling the stocking quantity, stocking time, and harvesting time of crabs, crayfish, and shrimp, the entire farming system is kept in a balanced state of development. Specifically, this invention harvests most of the crayfish during the crab's third molting period, effectively preventing the crab from increasing in size and activity range after molting, thus avoiding increased interspecies competition between crabs and crayfish and resulting in reduced production of crayfish and / or crabs. The stocking quantity of crabs, crayfish, and shrimp provided by this invention is reasonable. Increasing the stocking quantity of crabs, crayfish, or shrimp by one or more of these factors, based on the stocking quantity provided by this invention, does not increase the overall yield of the farming system; in fact, it decreases it. This further illustrates the rationality of the stocking quantity of crabs, crayfish, or shrimp in the technical solution provided by this invention. Attached Figure Description
[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0023] Figure 1 A simplified diagram of a crab-two-shrimp farming method;
[0024] Figure 2 A simplified diagram of a river crab molting. Detailed Implementation
[0025] This invention provides a method for farming one crab and two shrimp, comprising the following steps:
[0026] River crabs are released in February and March, crayfish in March and April, and freshwater shrimp in June for mixed shrimp and crab farming.
[0027] The crab-two-shrimp farming method provided by this invention involves stocking river crabs in February or March each year, more preferably adjusting the stocking time according to temperature during February or March. This invention does not specifically limit the species of river crabs; any river crabs conventionally farmed in this field can be used. In this invention, the river crabs can include both male and female crabs. In this invention, the river crabs are preferably juvenile crabs. This invention does not specifically limit the source of the river crabs, as long as they meet the corresponding specifications and conditions. The stocking size of the river crabs is preferably 60-160 crabs / kg, more preferably 80-100 crabs / kg, and more preferably 80 crabs / kg. The stocking density is preferably 700-1200 crabs / mu, more preferably 800-1000 crabs / mu, even more preferably 800-900 crabs / mu, and more preferably 800 crabs / mu. After stocking the river crabs, this invention preferably feeds them daily, with the daily feed standard preferably being 8%-12% of the crab's body weight, more preferably 10% of the crab's body weight. In this invention, the feeding is preferably done twice a day, namely a first feeding and a second feeding. The first feeding is preferably done in the morning; the amount of feed given in the first feeding is preferably 30% of the total daily feed mass. The second feeding is preferably done in the evening; the amount of feed given in the second feeding is preferably 70% of the total daily feed mass. Preferably, the feeding amount of the crabs is observed within two hours of each feeding to adjust the feeding amount for the following day.
[0028] This invention does not impose any special restrictions on the type of feed used; any conventional feed for river crabs can be used. After the river crabs are introduced, this invention does not impose any special restrictions on other farming conditions; any conventional farming conditions in the field can be used.
[0029] In the crab farming process described in this invention, the preferred peak period for crabs is from March 8th to March 15th (when they are in their first molt); from April 10th to April 17th (when they are in their second molt); from May 12th to May 27th (when they are in their third molt); from June 23rd to June 28th (when they are in their fourth molt); from June 25th to June 30th (when they are in their fourth molt); from August 1st to August 10th (when they are in their fifth molt); and from August 5th to August 15th (when they are in their fifth molt).
[0030] After releasing the river crabs, this invention preferably releases crayfish in March or April each year; more preferably, the release time is adjusted according to the temperature in March or April each year. This invention does not have a specific limitation on the species of crayfish; any crayfish conventionally farmed in the field can be used. In this invention, the crayfish are preferably early-bred crayfish seedlings in greenhouses or autumn-bred seedlings. This invention does not have a specific limitation on the source of the crayfish, as long as they meet the corresponding specifications and conditions. The preferred stocking density of the crayfish is 400-500 individuals / kg, more preferably 480-500 individuals / kg, and more preferably 500 individuals / kg. The preferred stocking density of the crayfish is 1500-2000 individuals / mu, more preferably 1800-2000 individuals / mu, and more preferably 2000 individuals / mu. After releasing the crayfish, this invention does not have a specific limitation on the farming conditions for the crayfish; they can be farmed under the same conditions as the river crabs. This invention does not require additional feeding for the crayfish during farming. In this invention, depending on the different feeding methods of shrimp and crabs, crayfish can utilize the small-particle feed produced by feeding river crabs, which is beneficial to maintaining good water quality.
[0031] After releasing crayfish, this invention preferably harvests them after ≥35 days of rearing, more preferably after 35 days, and even more preferably daily after 35 days. Harvesting the crayfish is preferably done every evening. The harvested crayfish are preferably ≥20 g each. Crayfish are preferably caught using traps. When harvesting, 70%–90% of the crayfish are preferably harvested before June, more preferably in April or May, and even more preferably during the third molting period. After harvesting 70%–90% of the crayfish, the remaining crayfish in the temporary rearing system are preferably harvested in September and thereafter. The crayfish harvested in September and after September as described in this invention preferably include crayfish harvested from September to November, crayfish harvested in winter, and / or crayfish harvested around the Spring Festival.
[0032] The growth cycle of crayfish is from March to June. This invention introduces river crabs in February to March, followed by crayfish in March to April. The third molting period for river crabs is from May 12th to May 27th each year. River crabs are relatively small, leaving ample space in the aquaculture system. During the first, second, and third molting periods, river crabs and crayfish are co-cultured. Since both require less space during this period, they can fully utilize the aquaculture system. This invention harvests 70% to 90% of the crayfish during the third molting period of river crabs. This is because after the third molt, river crabs are larger and have a wider range of movement, preventing competition between them and reducing production. Harvesting crayfish during this period also results in higher market value and greater economic benefits. The remaining 10% to 30% of the crayfish are preferably harvested in September and later. In this invention, the harvesting time in September and beyond preferably includes any one or two periods from September to November and the Spring Festival. In crayfish farming, this invention allows for a small-scale harvesting or no harvesting of crayfish in June depending on the farming situation. Since the market value of crayfish is low in June, the remaining crayfish are harvested primarily in September and beyond. This invention preferably avoids harvesting crayfish in July and August, as the price is low in August, and crayfish are dormant and difficult to harvest during this period. This invention harvests 70% to 90% of the crayfish during the third molting stage, and the remaining crayfish are harvested and marketed in September and beyond. This method of crayfish production achieves staggered market entry, effectively avoiding the problem of unsold crayfish.
[0033] After harvesting 70%–90% of the crayfish in the aquaculture system during the third molting stage of the river crabs, this invention introduces freshwater prawns in June. In this invention, the freshwater prawns are preferably berried freshwater prawns. Introducing berried freshwater prawns at this time is primarily due to the difficulty in controlling the quality of freshwater prawn larvae, which easily leads to the introduction of pathogens, and the low yield of freshwater prawn larvae in the first half of the year. In this invention, the larvae hatched by the berried freshwater prawns in June are generally fully grown into small freshwater prawn larvae by July. In this invention, the preferred species of freshwater prawn is Taihu No. 2 and / or Taihu No. 3. The freshwater prawns described in this invention have the advantages of rapid growth, large individual size, high yield, and strong disease resistance. The freshwater prawns described in this invention originate from local aquaculture farms in Taizhou. The preferred size of the freshwater prawns introduced in this invention is 4–5g / each, more preferably 4.8–5g / each, and even more preferably 5g / each. In this invention, the stocking density of the freshwater prawns is preferably 40-60 prawns / mu, more preferably 40-50 prawns / mu, and even more preferably 40 prawns / mu. After feeding the freshwater prawns, this invention does not impose special restrictions on the farming conditions of the freshwater prawns; they can be farmed under the same farming conditions as river crabs. After feeding the freshwater prawns, no additional feed is required, as the freshwater prawns can directly utilize the leftover feed from the river crabs.
[0034] In the first half of the year, the yield of freshwater prawn larvae is low, and their growth is uneven. The "one crab, two prawns" farming method provided in this invention involves stocking freshwater prawn larvae in June, after the river crabs have molted three times. By this time, crayfish begin burrowing in July, and the larvae of the stocked berried freshwater prawns have generally grown into small larvae by July. The timing of the stocking of freshwater prawns described in this invention effectively avoids interspecies competition between crayfish and freshwater prawns, ensuring that both the freshwater prawns and their larvae are in optimal growth condition.
[0035] After releasing the freshwater shrimp, this invention preferably allows harvesting to begin after 70-80 days of shrimp rearing, more preferably daily after 70-80 days of rearing. Harvesting is preferably carried out at night. The harvesting standard for freshwater shrimp is preferably >3g / shrimp. This invention preferably harvests river crabs simultaneously with the freshwater shrimp. The harvesting of both freshwater shrimp and river crabs is preferably carried out between September and November and / or during the Spring Festival. The harvesting of both freshwater shrimp and river crabs is preferably done using fish traps.
[0036] In the crab-two-shrimp farming method provided by this invention, the crabs molt from March to May each year during their first, second, and third molting periods. During these periods, the crabs are relatively small, leaving ample space in the farming system. Co-culturing crabs and crayfish during this time fully utilizes the system and effectively avoids interspecies competition, ensuring both species thrive. Since shrimp larvae production is low in the first half of the year and larvae growth is uneven, this invention releases shrimp larvae in June (after the crabs' third molt) and crayfish begin burrowing in July. By July, the released berried shrimp larvae have largely matured into small shrimp larvae, allowing both species to fully utilize the farming system and reducing interspecies competition. Meanwhile, shrimp and crabs have different feeding methods. Crayfish and freshwater shrimp can utilize leftover feed from crab feeding, thus maximizing feed utilization, maintaining good water quality, and improving the aquaculture environment. By stocking crayfish and freshwater shrimp, crab ponds can produce crayfish in the first half of the year and freshwater shrimp in the second half, making full use of the aquaculture system's conditions. The "one crab, two shrimp" aquaculture system provided by this invention employs seasonal, relay, and staggered farming methods, ensuring that crayfish, freshwater shrimp, and crabs are all in good growth condition, thereby improving the overall economic benefits of the aquaculture system. The "one crab, two shrimp" aquaculture method provided by this invention helps fishermen increase their income and contribute to rural revitalization. Shrimp and crabs are marketed seasonally in batches to meet different consumer demands. If the crayfish market is unfavorable, harvesting can be delayed, significantly reducing market risk.
[0037] This invention provides the application of the aquaculture method described in the above technical solution in increasing shrimp and crab production.
[0038] The crab-two-shrimp farming method provided by this invention can simultaneously harvest crayfish and freshwater shrimp while maintaining the yield and value of river crabs, and ensuring high and stable yields for both. The results of the embodiments show that the crab yield is 50-100 kg / mu, with a value of 5000-10000 yuan / mu; the crayfish yield is 25-60 kg / mu, with a value of 500-2000 yuan / mu; and the freshwater shrimp yield is 25-35 kg / mu, with a value of 1600-2400 yuan / mu.
[0039] To further illustrate the present invention, the technical solutions provided by the present invention will be described in detail below with reference to the accompanying drawings and embodiments, but these should not be construed as limiting the scope of protection of the present invention.
[0040] Example 1
[0041] In 2022, the Cai Gao Aquatic Products Farming Cooperative in Xinghua City planted aquatic plants in a 20-mu (approximately 3.3 hectares) pond with a water depth of 1.2 meters, according to the requirements for raising river crabs. On March 2nd, juvenile crabs were released at a stocking density of 1200 crabs per mu (approximately 80 crabs per hectare), with a stocking size of 60 crabs / kg. After stocking, the crabs were fed daily with a feed consisting of 50% pelleted feed and 50% fresh fish, with the total daily feed amount being 8%–10% of the crabs' body weight. The feeding method was as follows: 30% of the total feed was given in the morning, and 70% in the evening. The crabs' feeding behavior was observed 2 hours after each feeding, and the total feed amount for the following day was adjusted accordingly. On March 25th, crayfish larvae were released at a stocking density of 1800 larvae per mu (approximately 1200 larvae per mu). The release of crayfish can make full use of the aquatic space for the third molting stage of river crabs and the uneaten feed.
[0042] Large-scale harvesting and market launch can begin on May 16th. Depending on market demand, crayfish can be marketed once they reach 20g each. Crayfish will be caught using traps every night. Before June 1st (when river crabs are in the late molting stage), 30kg / mu of crayfish will be harvested. The remaining crayfish will be temporarily raised until September when prices are slightly higher to avoid peak season.
[0043] On June 15th, berried freshwater shrimp were released. The stocking size of the berried freshwater shrimp was 5g / shrimp, and the stocking density was 60 shrimp / acre. The shrimp can feed on excess plankton and uneaten feed. Starting in September, the freshwater shrimp and river crabs can be harvested and sold at the same time using traps. A small number of crayfish can be left in the pond and sold together with the freshwater shrimp and river crabs.
[0044] Table 1 shows the harvest time and yield per acre for crayfish, freshwater shrimp, and river crabs in this aquaculture system.
[0045] Table 1 shows the harvest time and yield per acre for crayfish, freshwater shrimp, and river crabs in the aquaculture system of Example 1.
[0046]
[0047] In Example 1, the yield of crayfish was 40 kg per mu, with a value of 1250 yuan per mu; the yield of freshwater shrimp was 32 kg per mu, with a value of 2560 yuan per mu; and the yield of river crab was 55 kg per mu, with a value of 5500 yuan per mu. The breeding cost increased slightly (mainly the cost of crayfish seedlings, berried freshwater shrimp, and breeding management) to 6000 yuan per mu, and the benefit was 3310 yuan per mu.
[0048] Example 2
[0049] In 2022, the Cai Gao Aquatic Products Farming Cooperative in Xinghua City planted aquatic plants in a 100-mu (approximately 6.7 hectares) pond with a water depth of 1 meter, following the requirements for raising river crabs. On March 10th, juvenile crabs were released at a stocking density of 100 crabs / kg and 1000 crabs / mu. They were fed daily with river crab feed (composed of 50% pelleted feed and 50% frozen fish), following the same feeding schedule as in Example 1. On April 4th, crayfish larvae were released at a stocking density of 400 larvae / kg and 2000 larvae / mu. The release of crayfish allowed for full utilization of the water space during the early third molting stage of the river crabs and the consumption of excess feed.
[0050] The crayfish can be harvested and sold on May 10th. Each crayfish weighing 20g can be sold. Crayfish will be caught every night using traps. 30kg / mu of crayfish will be harvested before June 1st. The remaining crayfish will be temporarily raised until September when prices are slightly higher to avoid peak season.
[0051] On June 20th, berried freshwater shrimp were stocked at a size of 4.8g each, with a stocking density of 40 shrimp per acre. The shrimp can feed on excess plankton and leftover feed. Starting in September, freshwater shrimp and river crabs can be harvested and sold simultaneously. A small number of crayfish can be left in the pond and sold together with the freshwater shrimp and river crabs.
[0052] Table 2 shows the harvest time and yield per acre for crayfish, freshwater shrimp, and river crabs in this aquaculture system.
[0053] Table 2 shows the harvest time and yield per acre for crayfish, freshwater shrimp, and river crabs in the aquaculture system of Example 2.
[0054]
[0055] In Example 2, the yield of crayfish was 35 kg per mu, with a value of 1,000 yuan per mu; the yield of freshwater shrimp was 28 kg per mu, with a value of 2,240 yuan per mu; and the yield of river crab was 58 kg per mu, with a value of 5,800 yuan per mu. The breeding cost remained the same (mainly due to the reduction in river crab seedlings and berried shrimp, and the increase in crayfish seedlings) at 6,000 yuan per mu, and the profit was 3,040 yuan per mu.
[0056] Example 3
[0057] In 2022, the Cai Gao Aquatic Products Farming Cooperative in Xinghua City planted aquatic plants in a 50-mu (approximately 3.3 hectares) pond with a water depth of 1.5 meters, following the requirements for raising river crabs. On March 1st, juvenile crabs were stocked at a size of 80 crabs / kg, with a stocking density of 800 crabs / mu. The crabs were fed daily with river crab feed (composed of 50% pelleted feed and 50% frozen fish), following the same feeding schedule as in Example 1. On March 14th, crayfish larvae were released at a size of 500 larvae / kg, with a stocking density of 2000 larvae / mu. The release of crayfish allowed for full utilization of the water space during the early third molting stage of the river crabs and the consumption of excess feed.
[0058] Crayfish can be harvested and sold on May 6th. Crayfish weighing 20g each can be sold. Crayfish will be caught every night using traps. Before June 1st, 25kg / mu of crayfish will be harvested. The remaining crayfish will be temporarily raised until September when prices are slightly higher to avoid peak season.
[0059] On June 8th, berried freshwater prawns were released at a size of 5g each, with a stocking density of 40 prawns per mu (approximately 0.16 acres). The prawns can feed on excess plankton and uneaten feed. Starting in September, freshwater prawns and river crabs can be harvested and marketed simultaneously. A small number of crayfish can be left in the pond and sold together with the freshwater prawns and river crabs.
[0060] Table 3 shows the harvest time and yield per acre for crayfish, freshwater shrimp, and river crabs in this aquaculture system.
[0061] Table 3 shows the harvest time and yield per mu for crayfish, freshwater shrimp, and river crabs in the aquaculture system of Example 3.
[0062]
[0063] In Example 3, the crayfish yield was 35 kg per mu, with a value of 1125 yuan per mu; the freshwater shrimp yield was 31 kg per mu, with a value of 2480 yuan per mu; and the river crab yield was 62 kg per mu, with a value of 6200 yuan per mu. The breeding cost decreased slightly (mainly due to the reduction in river crab seedlings and crabs) to 5800 yuan per mu, and the profit was 4005 yuan per mu.
[0064] Comparative Example 1-1
[0065] In 2022, the Cai Gao Aquatic Products Farming Cooperative in Xinghua City planted aquatic plants in a 40-mu (approximately 2 hectares) pond with a water depth of 1 meter, in accordance with the requirements for raising river crabs. River crabs were released on March 2nd at a stocking density of 90 crabs / kg, with a stocking density of 700 crabs / mu (approximately 66.7 hectares). Daily feeding of the crabs was the same as in Example 1. Starting in September, the crabs could be harvested and marketed using traps.
[0066] In this aquaculture system, the harvest time and yield per mu of river crabs are shown in Table 4-1.
[0067] Table 4-1 Comparative Example 1-1: Harvest Time and Yield per Mu of River Crab
[0068]
[0069] Comparative Example 1-1: The breeding cost is 5,000 yuan / mu, the yield is 60kg of river crabs per mu (this yield is considered high during 2020-2022), the price of river crabs is 100 yuan / kg, the breeding output value is 6,000 yuan / mu, and the profit is only 1,000 yuan / mu.
[0070] Comparative Examples 1-2
[0071] In 2022, the Cai Gao Aquatic Products Farming Cooperative in Xinghua City planted aquatic plants in a 40-mu (approximately 2 hectares) pond with a water depth of 1 meter, in accordance with the requirements for raising river crabs. River crabs were released on March 2nd at a stocking density of 60 crabs per kg, with a total stocking density of 1200 crabs per mu (approximately 667 hectares). Daily feeding of the crabs was the same as in Example 1. Starting in September, the crabs could be harvested and marketed using traps.
[0072] In this aquaculture system, the harvest time and yield per mu of river crabs are shown in Table 4-2.
[0073] Table 4-2 Harvest time and yield per mu of river crabs in Comparative Example 1-2
[0074]
[0075] According to Table 4-2, the breeding cost of Comparative Example 1-2 is 5,500 yuan / mu, the yield is 68 kg of river crabs per mu (this yield is considered high during the period of 2020-2022), the price of river crabs is 100 yuan / kg, the breeding output value is 6,800 yuan / mu, and the profit is only 1,300 yuan / mu.
[0076] Comparative Examples 1-3
[0077] In 2022, the Cai Gao Aquatic Products Farming Cooperative in Xinghua City planted aquatic plants in a 40-mu (approximately 2 hectares) pond with a water depth of 1 meter, in accordance with the requirements for raising river crabs. River crabs were released on March 2nd at a stocking density of 100 crabs / kg, with a stocking density of 1000 crabs / mu (approximately 667 hectares). Daily feeding of the crabs was the same as in Example 1. Starting in September, the crabs could be harvested and marketed using traps.
[0078] In this aquaculture system, the harvest time and yield per mu of river crabs are shown in Table 4-3.
[0079] Table 4-3 Harvest time and yield per mu of river crabs in Comparative Examples 1-3
[0080]
[0081] Table 4-3 shows that the breeding cost of Comparative Examples 1-3 is 5,500 yuan / mu, the yield is 66 kg of river crabs per mu (this yield is considered high during the period of 2020-2022), the price of river crabs is 100 yuan / kg, the breeding output value is 6,600 yuan / mu, and the profit is only 1,100 yuan / mu.
[0082] Comparative Examples 1-4
[0083] In 2022, the Cai Gao Aquatic Products Breeding Cooperative in Xinghua City planted aquatic plants in a 40-mu (approximately 2 hectares) pond with a water depth of 1 meter, in accordance with the requirements for raising river crabs. River crabs were released on March 2nd at a stocking density of 80 crabs / kg, with a total stocking density of 800 crabs / mu (approximately 600 crabs / acre). Daily feeding of the crabs was the same as in Example 1. Starting in September, the crabs could be harvested and marketed using traps.
[0084] In this aquaculture system, the harvest time and yield per mu of river crabs are shown in Table 4-4.
[0085] Table 4-4 Comparative Examples 1-4: Harvest Time and Yield per Mu of River Crabs
[0086]
[0087] Table 4-4 shows that the breeding cost of Comparative Examples 1-4 is 5,500 yuan / mu, the yield is 67 kg of river crabs per mu (this yield is considered high during the period of 2020-2022), the price of river crabs is 100 yuan / kg, the breeding output value is 6,700 yuan / mu, and the profit is only 1,200 yuan / mu.
[0088] Comparative Example 2
[0089] In 2022, the Cai Gao Aquatic Products Farming Cooperative in Xinghua City planted aquatic plants in a 50-mu (approximately 3.3 hectares) pond with a water depth of 1.5 meters, in accordance with the requirements for raising river crabs. On March 1st, juvenile crabs were released at a stocking density of 100 crabs / kg and 1000 crabs / mu. The daily feeding of the river crabs was the same as in Example 1. On March 14th, crayfish larvae were released at a stocking density of 3000 larvae / mu, with a stocking density of 500 larvae / kg. The release of crayfish allowed for full utilization of the aquatic space during the early third molting stage of the river crabs and the consumption of excess feed.
[0090] The crayfish can be harvested and sold on May 6. Depending on market demand, crayfish can be sold when they reach 20g each. Crayfish will be caught every night using traps, and 45kg / mu of crayfish will be harvested before June 1. The remaining crayfish will be temporarily raised until September when prices are slightly higher to avoid peak season.
[0091] On June 8th, berried freshwater prawns were released. The stocking size of the berried freshwater prawns was 6g each, and the stocking density was 45 prawns per mu (approximately 0.067 hectares). The freshwater prawns can feed on excess plankton and uneaten feed. Starting in September, freshwater prawns and river crabs can be harvested and sold at the same time. A small number of crayfish can be left in the pond and sold together with the freshwater prawns and river crabs.
[0092] Table 5 shows the harvest time and yield per acre for crayfish, freshwater shrimp, and river crabs in this aquaculture system.
[0093] Table 5 shows the harvest time and yield per mu for crayfish, freshwater shrimp, and river crabs in Comparative Example 2 aquaculture system.
[0094]
[0095] In this aquaculture system, the yield of crayfish is 55 kg per mu, with a value of 1625 yuan per mu; the yield of freshwater shrimp is 20 kg per mu, with a value of 1600 yuan per mu; and the yield of river crab is 45 kg per mu, with a value of 4500 yuan per mu. The breeding cost has increased slightly (mainly due to the cost of crayfish seedlings) to 6100 yuan per mu, and the profit is only 1625 yuan per mu.
[0096] Comparative Example 3
[0097] The farming method for one crab and two shrimp is the same as in Example 3, except that on March 14, crayfish seedlings are released at a size of 500 shrimp / kg and a stocking density of 4000 shrimp / mu.
[0098] 50 kg / mu of crayfish will be harvested before June 1st, and the remaining crayfish will be temporarily raised until September when prices are slightly higher to avoid peak season.
[0099] Table 6 shows the harvest time and yield per acre for crayfish, shrimp, and crab in this aquaculture system.
[0100] Table 6 shows the harvest time and yield per mu for crayfish, freshwater shrimp, and river crabs in Comparative Example 3 aquaculture system.
[0101]
[0102] Table 6 shows that the yield of crayfish is 62 kg per mu (approximately 0.067 hectares), with a value of 1850 yuan per mu; the yield of freshwater shrimp is 15 kg per mu, with a value of 1200 yuan per mu; and the yield of river crab is 35 kg per mu, with a value of 3500 yuan per mu. The breeding cost has slightly increased (mainly due to the cost of crayfish seedlings) to 6100 yuan per mu, resulting in a profit of 450 yuan per mu. While the increased stocking density of crayfish has increased crayfish production, it has negatively impacted the yields of both river crabs and freshwater shrimp, particularly river crabs, whose yield has significantly decreased, with a value of only 6550 yuan per mu, resulting in a substantial reduction in profitability. This explains why many farmers are hesitant to co-culture crayfish and freshwater shrimp in crab ponds. Co-culturing crayfish and freshwater shrimp in crab ponds places higher demands on management throughout the entire breeding period.
[0103] Comparative Example 4
[0104] The farming method for one crab and two crayfish is the same as in Example 3, except that crayfish are harvested and marketed starting May 15th, with 50kg of crayfish harvested before August 1st. The remaining crayfish are temporarily held until September when prices are slightly higher to avoid peak season.
[0105] The harvest time and yield per mu for crayfish, shrimp, and river crab in this aquaculture system are shown in Table 7.
[0106] Table 7 shows the harvest time and yield per acre for crayfish, freshwater shrimp, and river crabs in Comparative Example 4 aquaculture system.
[0107]
[0108] Table 7 shows that the yield of crayfish is 50 kg per mu, with a value of 1975 yuan per mu; the yield of freshwater shrimp is 20 kg per mu, with a value of 1600 yuan per mu; and the yield of river crab is 35 kg per mu, with a value of 3500 yuan per mu. The breeding cost has increased slightly (mainly the cost of feed and management) to 6100 yuan per mu, and the profit is 975 yuan per mu.
[0109] The delayed market launch of crayfish, coupled with the increased size of crayfish available at market, has led to a slight increase in price, but it remains cheaper compared to prices after September. Meanwhile, the fact that crayfish are harvested until August has squeezed the living space of river crabs, resulting in a decrease in river crab production. Ultimately, the output value per mu (unit of land area) was 7075 yuan.
[0110] Comparative Example 5
[0111] The farming method for one crab and two shrimp is the same as in Example 3, except that berried shrimp are released on June 8th, with a release size of 6g / shrimp and a release density of 80 shrimp / acre.
[0112] The harvest time and yield per mu for crayfish, freshwater shrimp and river crab in this aquaculture system are shown in Table 8.
[0113] Table 8 shows the harvest time and yield per mu for crayfish, freshwater shrimp, and river crab in Comparative Example 5 aquaculture system.
[0114]
[0115] Table 8 shows that the yield of crayfish is 39 kg per mu (approximately 0.067 hectares), with a value of 1250 yuan per mu; the yield of freshwater prawns is 33 kg per mu, with a value of 2640 yuan per mu; and the yield of river crabs is 54 kg per mu, with a value of 5400 yuan per mu. The breeding cost has increased slightly (mainly due to the cost of berried freshwater prawns and feed) to 6080 yuan per mu, resulting in a profit of 3210 yuan per mu. The release of berried freshwater prawns on June 8th will not affect the production of crayfish in the first half of the year. However, the yield of freshwater prawns harvested from September to November will not increase due to the increased release of berried freshwater prawns. This is because the prawn larvae hatched from berried freshwater prawns at this time are in a weak growth state. On the one hand, they are affected by predation and survival competition from crayfish and river crabs; on the other hand, freshwater prawn larvae feed on zooplankton, and there is not enough zooplankton to support the survival of an excessive number of larvae. Therefore, a stocking density of 50 berried freshwater prawns per mu is more suitable in river crab ponds.
[0116] The input and yield details of the combined crab-two-shrimp farming methods in Examples 1-3 and Comparative Examples 1-5 are shown in Table 9.
[0117] Table 9. Input and yield of the crab-two-shrimp farming methods in Examples 1-3 and Comparative Examples 1-5
[0118]
[0119] Comparing the yields of Examples 1-3 and Comparative Examples 1-5, it was found that the yields of juvenile crabs, crayfish, and freshwater shrimp fluctuated depending on the input size, but the overall yield remained relatively stable at 120-130 kg / mu.
[0120] Comparison of Examples 1-3 and Comparative Examples 1-1-4 shows that the crab-two-shrimp farming method provided by the present invention can maintain the crab yield while also harvesting crayfish and freshwater shrimp, thus increasing the overall yield.
[0121] A comparison of Example 2 and Comparative Example 2 shows that increasing the amount of crayfish and the size of the crayfish increases the yield of crayfish, but does not increase the yield of crayfish; in fact, it tends to decrease. The yield of juvenile crabs also decreases significantly.
[0122] A comparison of Example 3 and Example 4 shows that increasing the amount of crayfish significantly increased the crayfish yield, while significantly decreasing the yield of crabs and prawns, thus reducing the overall efficiency.
[0123] A comparison of Example 3 and Comparative Example 4 shows that delaying the harvest time of crayfish will significantly reduce the yield of juvenile crabs and freshwater shrimp. In the one-crab-two-shrimp farming method of the present invention, harvesting 70% to 90% of the crayfish before 6 months is the key to achieving an overall increase in production.
[0124] In summary, the crab-two-shrimp farming method provided by this invention adopts seasonal farming, relay farming, and staggered farming methods, which can ensure that crayfish, shrimp, and crabs are all in good growth condition, thereby improving the economic benefits of the entire farming system. The harvesting method of shrimp and crabs being marketed in batches in different seasons can meet different consumer demands. If the crayfish market is not good, the harvest can be postponed, which can significantly reduce market risks.
[0125] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention, and not all embodiments. People can obtain other embodiments based on these embodiments without creative effort, and these embodiments all fall within the protection scope of the present invention.
Claims
1. A method for breeding one crab and two shrimps, characterized in that, The method comprises the following steps: The mixed culture of shrimps and crabs is carried out by releasing river crabs in February to March each year, releasing crayfish in March to April, and releasing green shrimps in June; The releasing size of river crabs is 60 to 160 per kg, and the releasing density is 700 to 1200 per mu; the releasing size of crayfish is 400 to 500 per kg, and the releasing density is 1500 to 2000 per mu; the releasing size of green shrimps is 4 to 5 g per shrimp, and the releasing density is 40 to 60 per mu; 70% to 90% of crayfish are harvested before June, and the rest of crayfish are harvested in September and after September; The harvesting time of green shrimps and river crabs is from September to November and / or during the Spring Festival.
2. The farming method according to claim 1, characterized in that, The green shrimps are egg-carrying green shrimps; the varieties of the green shrimps include Taihu No. 2 and / or Taihu No.
3.
3. The farming method according to claim 1, characterized in that, The harvesting time of crayfish from September to after September includes any time period or two time periods from September to November or during the Spring Festival.
4. The farming method according to claim 1, characterized by, The crayfish are harvested when the culture time is greater than or equal to 35 days; the weight of the crayfish is greater than or equal to 20 g per crayfish when the crayfish are harvested.
5. The farming method according to claim 1, characterized in that, The green shrimps are harvested when the culture time is 70 to 80 days.
6. The farming method according to claim 1, characterized in that, The river crabs are fed during the culture; the feeding amount per day is 8% to 12% of the weight of the river crabs.
7. Application of the culture method according to any one of claims 1 to 6 in improving the yield of shrimps and crabs.