Method for predicting shelling time of river crabs and application thereof

Abstract

The invention provides a method for predicting the shelling time of river crabs and application of the method, and belongs to the technical field of river crab breeding. The method disclosed by the invention is scientific and accurate, is more accurate and reliable compared with experience discrimination, has operability and repeatability, and can be used for quickly discriminating even people without breeding experience. The method provided by the invention can accurately predict the molting time of the river crabs, guide river crab breeding personnel to adjust management measures, improve the growth speed of the river crabs and reduce the death rate of the river crabs.

Description

Technical Field

[0001] The present invention belongs to the technical field of Eriocheir sinensis culture, and particularly relates to a method for predicting the molting time of Eriocheir sinensis and its application. Background Art

[0002] The scientific name of Eriocheir sinensis is Eriocheir sinensis, which is an economic crab and one of the traditional precious aquatic products. Eriocheir sinensis grows fast, has large specifications, strong disease resistance, and delicious taste, and is one of the favorite delicacies of people. The culture of Eriocheir sinensis provides a way to get rich and employment opportunities for many farmers.

[0003] The biological characteristics of Eriocheir sinensis determine that molting is an important link in the process of Eriocheir sinensis culture. The molting of Eriocheir sinensis generally includes intermolt, premolt, molt, postmolt, and subsequent period. Intermolt: Eating a large amount of food to accumulate energy substances and trace elements. Premolt: The dermis layer and the epidermis layer begin to separate, the old shell epidermis is absorbed, and a new epidermis gradually forms. After the new epidermis forms, Eriocheir sinensis begins to absorb water. The water promotes the softening of the chitin for subsequent molting preparation. Molt: Eriocheir sinensis absorbs a large amount of water, and cracks appear in the carapace, and then it escapes from the old shell. At this time, the shell is soft and very fragile, and is vulnerable to attack. Postmolt: When it is just molted, the new shell of Eriocheir sinensis is soft and elastic. Eriocheir sinensis begins to absorb a large amount of water to fully stretch the new shell to the maximum scale. At this time, its vitality is weak and it does not feed. Subsequent period: The carapace of Eriocheir sinensis begins to calcify, and it begins to absorb a large amount of calcium and trace elements. This process depends on the calcium content and trace element content in the water body. The lack of trace elements will make the shell of Eriocheir sinensis soft, increase the hardening time of the shell or prevent it from fully hardening, increasing the risk of death of Eriocheir sinensis during the molting period. After the shell hardens and can support the body, Eriocheir sinensis will excrete the excessive water absorbed by the body and begin to feed, completing a molting cycle.

[0004] Therefore, accurately mastering the molting time of Eriocheir sinensis and targeted adjustment of aquaculture management measures can improve the aquaculture survival rate and increase the aquaculture benefits. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide a method for predicting the molting time of Eriocheir sinensis, which can accurately predict the molting time of Eriocheir sinensis and provide a basis for adjusting aquaculture management measures.

[0006] In order to achieve the above-mentioned invention purpose, the present invention provides the following technical solutions:

[0007] A method for predicting the molting time of Eriocheir sinensis includes the following steps: collecting data records of the water temperature of Eriocheir sinensis culture and the molting time of Eriocheir sinensis; calculating the effective accumulated temperature K during each molting period of Eriocheir sinensis; calculating the average value K of the effective accumulated temperature of all the collected data μ ; monitoring the real-time water temperature of Eriocheir sinensis culture and calculating the reached effective accumulated temperature K d, calculate the average effective accumulated temperature K for three consecutive days w as the predicted effective accumulated temperature for the next day; establish a formula for predicting the molting time to calculate the predicted molting time of Chinese mitten crabs. The formula for predicting the molting time is: D = d + (K μ - K d ) / (K w - T0), where D is the predicted molting time, d is the current time, T0 is the biological zero degree of Chinese mitten crabs. When the predicted values for three consecutive days are the same, then this predicted value is the predicted molting time of Chinese mitten crabs.

[0008] Preferably, collect data records of water temperature and molting time of Chinese mitten crabs for more than three years.

[0009] Preferably, statistically analyze the average water temperature T every day during the molting cycle of Chinese mitten crabs for calculating the effective accumulated temperature K during each molting period of Chinese mitten crabs.

[0010] Preferably, the average water temperature T is the average value of the water temperature recorded once per hour for 24 hours on the same day.

[0011] Preferably, the water temperature is the bottom water temperature of the breeding environment.

[0012] Preferably, the formula for calculating the effective accumulated temperature K during each molting period of Chinese mitten crabs is: where Ti is the average water temperature on the i-th day, T0 is the biological zero degree of Chinese mitten crabs, and n is the number of days in the molting cycle of Chinese mitten crabs.

[0013] Preferably, T0 = 5°C. When Ti < 5°C, the effective accumulated temperature is 0.

[0014] Preferably, the molting cycle of Chinese mitten crabs is from the first day after molting ends to the day before the next molting begins.

[0015] Another object of the present invention is to provide the application of the method for predicting the molting time of Chinese mitten crabs in the aquaculture management of Chinese mitten crabs.

[0016] Another object of the present invention is to provide the application of the method for predicting the molting time of Chinese mitten crabs in the breeding of Chinese mitten crabs.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] The present invention provides a method for predicting the molting time of Chinese mitten crabs. The method of the present invention is scientific and accurate, more accurate and reliable than empirical discrimination, and has operability and repeatability. Even personnel without aquaculture experience can make rapid discrimination. The method of the present invention has a low cost, only requires some temperature monitoring equipment, and the data statistical analysis is relatively simple without additional investment. During the molting period, the individuals of Chinese mitten crabs are extremely vulnerable, and the use of drugs (conventional aquaculture drugs include disinfectants and modifiers for water quality regulation and disease prevention agents) will lead to an increase in the mortality rate of Chinese mitten crabs. The method provided by the present invention can accurately predict the molting time of Chinese mitten crabs, and can stop the use of drugs in advance, thereby reducing the mortality rate. At the same time, a large amount of calcium and magnesium ions are required during the molting and growth process of Chinese mitten crabs. By accurately predicting the molting time of Chinese mitten crabs by adopting the method of the present invention and adding elements such as calcium and magnesium required for molting in the bait feeding after predicting the molting time, growth can be promoted and the growth rate can be increased. Detailed implementation mode

[0019] The present invention provides a method for predicting the molting time of Chinese mitten crabs, comprising the following steps: collecting data records of the water temperature for culturing Chinese mitten crabs and the molting time of Chinese mitten crabs; statistically analyzing the average water temperature T per day within the molting cycle of Chinese mitten crabs; calculating the effective accumulated temperature K during each molting period of Chinese mitten crabs; calculating the average value K of the effective accumulated temperature of all the collected data μ ; monitoring the real-time water temperature for culturing Chinese mitten crabs, calculating the reached effective accumulated temperature K d , calculating the average effective accumulated temperature K for three consecutive days w as the predicted effective accumulated temperature for the next day; establishing a formula for predicting the molting time to calculate the predicted molting time of Chinese mitten crabs, and the formula for predicting the molting time is: D = d + (K μ - K d ) / (K w - T0), where D is the predicted molting time, d is the current time, T0 is the biological zero degree of Chinese mitten crabs, and when the predicted values for three consecutive days are the same, then this predicted value is the predicted molting time of Chinese mitten crabs.

[0020] In the method provided by the present invention, it is preferably to collect data records of the water temperature for culturing Chinese mitten crabs and the molting time of Chinese mitten crabs for more than three years; the molting cycle of Chinese mitten crabs is from the first day after the molting ends to the day before the next molting starts. If it is the first molting, the molting cycle of Chinese mitten crabs is recorded as 30 days, and the first molting refers to the first molting of spring juvenile crabs; statistically analyzing the average water temperature T per day within the molting cycle of Chinese mitten crabs for calculating the effective accumulated temperature K during each molting period of Chinese mitten crabs, and the average water temperature T per day within the molting cycle of Chinese mitten crabs is the bottom water temperature of the culture environment for detecting the water temperature, recording the water temperature once per hour, and calculating the average value of the water temperature recorded for 24 hours on the same day, and the bottom water temperature is the water temperature recorded at a position 0 - 10 cm from the bottom of the culture environment; the formula for calculating the effective accumulated temperature K during each molting period of Chinese mitten crabs is: ; where \(T_i\) is the average water temperature on the \(i\)-th day, \(T_0\) is the biological zero degree of the Chinese mitten crab, \(n\) is the number of days of the molting cycle of the Chinese mitten crab. The biological zero degree of the Chinese mitten crab is the lowest temperature at which the Chinese mitten crab begins to grow. In the present invention, \(T_0 = 5^{\circ}C\). When \(T_i < 5^{\circ}C\), the effective accumulated temperature is 0. The average value \(K\) of the effective accumulated temperature of all the data collected and calculated in the present invention μ , taking the \(K\) μ as the effective accumulated temperature threshold for predicting the molting of Chinese mitten crabs.

[0021] In the present invention, when predicting the first molting time of Chinese mitten crabs, the data statistically collected are the records of the breeding water temperature and the molting time of Chinese mitten crabs during the first molting cycle over the years; when predicting the second molting time of Chinese mitten crabs, the data statistically collected are the records of the breeding water temperature and the molting time of Chinese mitten crabs during the second molting cycle over the years; and so on. When predicting the \(n\)-th molting time of Chinese mitten crabs, the data statistically collected are the records of the breeding water temperature and the molting time of Chinese mitten crabs during the \(n\)-th molting cycle over the years, where \(n\geq1\).

[0022] The present invention also provides the application of the method for predicting the molting time of Chinese mitten crabs in the breeding management of Chinese mitten crabs. Accurately predicting the molting time of Chinese mitten crabs helps to guide the breeders to reasonably plan the time for using drugs and the types of baits during the breeding process of Chinese mitten crabs, thereby reducing the mortality rate of Chinese mitten crabs and promoting the growth of Chinese mitten crabs. Preferably, the breeders can adjust the breeding management 2 - 3 days before the predicted molting time of Chinese mitten crabs.

[0023] The present invention also provides the application of the method for predicting the molting time of Chinese mitten crabs in the breeding of Chinese mitten crabs. By accurately predicting the molting time of Chinese mitten crabs and taking reasonable management measures, the present invention helps to improve the survival rate of Chinese mitten crabs, and further helps to improve the breeding efficiency and shorten the breeding time.

[0024] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0025] Example 1

[0026] A method for predicting the molting time of Chinese mitten crabs includes the following steps:

[0027] Collect the data records of the breeding water temperature and the molting time of Chinese mitten crabs for more than three years;

[0028] Statistically calculate the average water temperature \(T\) every day during the molting cycle of Chinese mitten crabs (from the first day after the molting ends to the day before the next molting begins). The water temperature is the water temperature at a position 0 - 10 cm from the bottom of the breeding environment, and it is recorded once every hour. The average value of the water temperature recorded in 24 hours on the same day is the average water temperature \(T\);

[0029] Calculate the effective accumulated temperature \(K\) during each molting period of Chinese mitten crabs. The calculation formula is: Where Ti is the average water temperature on the i-th day, T0 is the biological zero temperature of the Chinese mitten crab, T0 = 5°C, and n is the number of days in the molting cycle of the Chinese mitten crab; when Ti < 5°C, the effective accumulated temperature is 0;

[0030] Calculate the average value K of the effective accumulated temperature of all the collected data μ , and use the K μ as the effective accumulated temperature threshold for predicting the molting of Chinese mitten crabs;

[0031] Monitor the real-time water temperature of Chinese mitten crab farming, calculate the reached effective accumulated temperature K d , and calculate the average effective accumulated temperature K for 3 consecutive days w as the predicted effective accumulated temperature for the next day;

[0032] Establish a formula for predicting the molting time to calculate the predicted molting time of Chinese mitten crabs. The formula for predicting the molting time is: D = d + (K μ - K d ) / (K w - T0), where D is the predicted molting time, d is the current time, and T0 is the biological zero temperature of the Chinese mitten crab. When the predicted values for 3 consecutive days are the same, then this predicted value is the predicted molting time of the Chinese mitten crab.

[0033] Example 2

[0034] Adopt the method of Example 1 to predict the first molting time of Chinese mitten crabs in the breeding base of Guanghe Crab Industry Co., Ltd.

[0035] The Chinese mitten crab variety is Guanghe No. 1. Collect the data records of water temperature and Chinese mitten crab molting time during the first molting period of Chinese mitten crab farming from 2018 to 2022, and statistically calculate the average water temperature T every day during the molting cycle, as shown in Table 1. The water temperature statistics are from April 1st to the day before molting.

[0036] Table 1 Water temperature and Chinese mitten crab molting time during the first molting period of Chinese mitten crab farming

[0037]

[0038]

[0039] Calculate the effective accumulated temperature during the first molting of Chinese mitten crabs. In the formula, K is the effective accumulated temperature, Ti is the average water temperature on the i-th day, T0 is the biological zero temperature of the Chinese mitten crab, T0 = 5°C, and n is the number of days in the molting cycle of the Chinese mitten crab. When the average temperature is lower than 5°C, the effective accumulated temperature is 0. The results are shown in Table 2.

[0040] Table 2 Effective accumulated temperature during the first molting of Chinese mitten crabs

[0041]

[0042]

[0043] Calculate the average effective accumulated temperature K during the first molting period of Chinese mitten crab farming from 2018 to 2022 μ As the threshold of effective accumulated temperature for predicting the molting of Chinese mitten crab. According to the effective accumulated temperature recorded in Table 2, calculate the average effective accumulated temperature K from 2018 to 2022 μ = 229.7 °C·day

[0044] Monitor the breeding water temperature and calculate the currently reached effective accumulated temperature K d , calculate the average temperature K for 3 consecutive days w As the predicted temperature value for the next day.

[0045] Establish a formula for predicting the molting time: D = d + (K μ - K d ) / (K w - T0), predict the molting time, where D is the predicted molting time, d is the current time, T0 is the biological zero degree of Chinese mitten crab, T0 = 5 °C. When the predicted values for 3 consecutive days are the same, it is considered that the predicted molting time is the accurate molting time.

[0046] In 2023, by predicting the molting time of Chinese mitten crab, the results are shown in Table 3. The predicted molting time is May 4th, and the actual molting time is May 3rd. It can be seen that the prediction accuracy is relatively high.

[0047] Table 3 Prediction results of Chinese mitten crab molting time

[0048]

[0049]

[0050] According to the prediction results, the present invention adjusted the breeding management measures on May 1, 2023, effectively improving the growth rate of Chinese mitten crab and reducing the mortality rate of Chinese mitten crab. It can be seen that the method of the present invention can be used to guide breeding management.

[0051] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A method for predicting the molting time of Chinese mitten crabs, characterized in that, It includes the following steps: Collect data records of the water temperature for river crab farming and the molting time of river crabs; calculate the effective accumulated temperature K during each molting period of river crabs; calculate the average value K of the effective accumulated temperature of all the collected data μ ; Monitor the real-time water temperature of river crab farming and calculate the reached effective accumulated temperature K d , calculate the average effective accumulated temperature K for 3 consecutive days w as the predicted effective accumulated temperature for the next day; establish a formula for predicting the molting time to calculate the predicted molting time of river crabs. The formula for the predicted molting time is: D = d + (K μ - K d ) / (K w - T0), where D is the predicted molting time, d is the current time, and T0 is the biological zero degree of river crabs. When the predicted values for 3 consecutive days are the same, then this predicted value is the predicted molting time of river crabs.

2. The method according to claim 1, wherein Collect data records of the water temperature for Chinese mitten crab farming and the molting time of Chinese mitten crabs for more than three years.

3. The method according to claim 1, wherein Statistically calculate the average water temperature T per day during the molting cycle of Chinese mitten crabs for calculating the effective accumulated temperature K during each molting period of Chinese mitten crabs.

4. The method according to claim 3, wherein The average water temperature T is to record the water temperature once per hour and calculate the average value of the water temperature recorded in 24 hours of the day.

5. The method according to claim 4, characterized in that, The water temperature is the bottom water temperature of the farming environment.

6. The method according to claim 1, characterized in that The formula for calculating the effective accumulated temperature K during each molting period of Chinese mitten crabs is as follows: where Ti is the average water temperature on the i-th day, T0 is the biological zero degree of Chinese mitten crabs, and n is the number of days of the molting cycle of Chinese mitten crabs.

7. The method according to claim 6, characterized in that When T0 = 5°C and Ti < 5°C, the effective accumulated temperature is 0.

8. The method according to claim 1, wherein The molting cycle of Chinese mitten crabs is from the first day after molting ends to the day before the next molting begins.

9. Application of the method for predicting the molting time of Chinese mitten crabs according to any one of claims 1 to 8 in the farming management of Chinese mitten crabs.

10. Application of the method for predicting the molting time of Chinese mitten crabs according to any one of claims 1 to 8 in the breeding of Chinese mitten crabs.

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