Method for increasing survival rate of bighead carp fingerling bred in saline-alkali water

Abstract

The invention discloses a method for increasing the survival rate of bighead carp saline-alkali water increased culture fingerlings, and relates to the technical field of fish culture. The method aims at solving the problems that in the medium-high saline-alkali water culture and proliferation process of bighead carps in northeast China, when fingerlings cultured in a fresh water pond come out of the pond and are directly put into medium-high saline-alkali water in spring and autumn, the fish bodies have severe stress reactions, and when the stress reactions exceed the bearing range of the fish bodies, individual death often occurs, and the survival rate of the bighead carps is high. The survival rate of the thrown fingerlings is low; and the economic benefit of culture and proliferation is poor. According to the method, the target saline-alkali lake, the foul marsh and other water bodies are used for preparing the low-alkali pond water body with the maximum alkalinity value of 1 / 3-1 / 2 concentration of bighead carp fingerling saline-alkali water proliferation and culture, through adaptive domestication of fish bodies, the stress resistance of the fish bodies can be enhanced, and the stress reaction of fingerling cultured in a fresh water pond directly put into the medium-high saline-alkali water body is relieved. The method for improving the survival rate of the bighead carp saline-alkali water increased culture fingerling can be obtained.

Description

Technical Field

[0001] The invention relates to the technical field of fish breeding, and in particular to a method for improving the survival rate of bighead carp fish species cultured in saline-alkali water. Background Art

[0002] Bighead carp (Aristichthys nobilis), also known as silver carp, is one of the important bulk freshwater fish for aquaculture in large and medium-sized water surfaces such as lakes and reservoirs in my country. According to the data, the output of bighead carp in 2023 was as high as 3,349,884 tons, second only to grass carp and silver carp, ranking third in freshwater fish aquaculture output. Because bighead carp and silver carp mainly filter plankton in water bodies through gill filaments in natural waters such as lakes and reservoirs, they become important fish for purifying water quality and ensuring green ecological fisheries. Through a large number of production practices, it is found that in the process of aquaculture of fish in large water surfaces such as saline-alkali lakes and swamps, bighead carp has more advantages than silver carp. It has a fast growth rate, a high survival rate, and good economic benefits. It is the main fish for aquaculture in inland saline-alkali waters.

[0003] my country has a large number of saline-alkali lakes, marshes and other water resources. The saline-alkali area in Northeast China is a typical carbonate water body. Due to the complex and diverse ion composition types and the large difference in salinity and alkali concentration, fishery production has always been at a low level. A large number of studies have shown that high alkali is the main key factor restricting the development of fisheries in saline-alkali water bodies. In the process of aquaculture of bighead carp in medium and high saline-alkali water bodies, the fish species released in spring and autumn often die due to excessive alkalinity in the water body. Therefore, how to improve the survival rate of fish species released in saline-alkali water aquaculture and expand the area of ​​saline-alkali waters suitable for fishing is an important means to ensure the sustainable and stable development of fisheries in the region. The main reason is that the fish species released in spring and autumn in saline-alkali lakes, marshes and other waters are mostly cultivated in freshwater ponds. After leaving the pond, they are directly released into higher saline-alkali water bodies. The fish will have a severe stress response. When it exceeds the range that the fish body can bear, individual deaths often occur, resulting in low survival rate of released fish species and poor economic benefits of aquaculture. Summary of the invention

[0004] The purpose of the present invention is to solve the problem that in the process of aquaculture of bighead carp in medium- and high-salinity and alkaline water in Northeast China, fish species cultivated in freshwater ponds are directly released into medium- and high-salinity and alkaline water bodies in spring and autumn, and the fish bodies will have severe stress reactions. When the stress exceeds the tolerance range of the fish bodies, individual deaths often occur, resulting in low survival rate of the released fish species and poor economic benefits of aquaculture. A method for improving the survival rate of bighead carp aquacultured in saline-alkali water is provided.

[0005] A method for improving the survival rate of bighead carp in saline-alkali water aquaculture is carried out according to the following steps:

[0006] Step S1:

[0007] Cultivate the bighead carp fry bred in spring in a freshwater pond, and in autumn or the spring of the second year, when the bighead carp fingerlings grow to 1 to 2 years old, measure the mortality rate of the bighead carp fingerlings in water bodies with different alkalinity values ​​within 12 to 96 hours, and then calculate the median lethal concentration value of the bighead carp fingerlings within 12 to 96 hours based on the mortality rate, and use 1 / 2 of the median lethal concentration value as the maximum alkalinity value for the aquaculture of bighead carp fingerlings in saline-alkali water;

[0008] Step S2:

[0009] Before releasing the bighead carp fingerlings cultivated in the freshwater pond into the target saline-alkali lake or saline-alkali marsh, the bighead carp fingerlings are first released into a low-alkali pond water body for adaptive domestication, wherein the alkalinity value of the low-alkali pond water body is 1 / 3 to 1 / 2 of the maximum alkalinity value of the saline-alkali water aquaculture in step S1;

[0010] Step S3:

[0011] After the bighead carp fingerlings are domesticated in the low-alkali pond water in step S2 for 5 to 7 days, they are fished out of the pond and put into the target saline-alkali lake or saline-alkali marsh for breeding.

[0012] Beneficial effects of the present invention:

[0013] (1) The present invention calculates the median lethal concentration of bighead carp within 12 to 96 hours based on the mortality rate of bighead carp in water bodies with different alkalinity values ​​within 12 to 96 hours, and determines the maximum alkalinity value of bighead carp in saline-alkali water according to experimental results and production experience. Then, target saline-alkali lakes, marshes and other water bodies suitable for bighead carp aquaculture are screened and determined, avoiding the problem of low survival rate of fish species due to high alkalinity of the water body, which causes the fish to be easily killed due to stress.

[0014] (2) The present invention utilizes target saline-alkali lakes, marshes and other water bodies to prepare low-alkali pond water with a concentration of 1 / 3 to 1 / 2 of the maximum alkalinity value for saline-alkali water aquaculture of bighead carp fingerlings. Through the adaptive domestication of the fish bodies, the stress resistance of the fish bodies can be enhanced, and the stress response of fish fingerlings cultivated in freshwater ponds directly placed in medium- and high-salinity water bodies can be reduced.

[0015] (3) The present invention takes the fish species cultured in freshwater ponds and releases them into low-alkali ponds for adaptive domestication for 5 to 7 days. The fish species are then released into saline-alkali lakes, marshes and other water bodies for aquaculture, which can significantly improve the survival rate of fish species aquacultured in medium- and high-salinity water bodies.

[0016] The invention can obtain a method for improving the survival rate of bighead carp fish species cultured in saline-alkali water. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1It means that fish species that have not been adapted to domestication are placed in 50mmol / L high-alkaline water, and the intestinal tissue is sampled for 24 hours;

[0018] Figure 2 This is a diagram of the intestinal tissue of fish that have been adapted to 15mmol / L low-alkaline water for 5 days and then placed in 50mmol / L high-alkaline water and sampled for 24 hours;

[0019] Figure 3 A diagram showing the operation process of calculating the median lethal concentration using SPSS27.00;

[0020] Figure 4 A diagram showing the operational process of calculating the half-lethal concentration using SPSS27.00. DETAILED DESCRIPTION

[0021] Specific implementation method 1: This implementation method is a method for improving the survival rate of bighead carp in saline-alkali water aquaculture, which is carried out according to the following steps:

[0022] Cultivate the bighead carp fry bred in spring in a freshwater pond, and in autumn or the spring of the second year, when the bighead carp fingerlings grow to 1 to 2 years old, measure the mortality rate of the bighead carp fingerlings in water bodies with different alkalinity values ​​within 12 to 96 hours, and then calculate the median lethal concentration value of the bighead carp fingerlings within 12 to 96 hours based on the mortality rate, and use 1 / 2 of the median lethal concentration value as the maximum alkalinity value for the aquaculture of bighead carp fingerlings in saline-alkali water;

[0023] Step S2:

[0024] Before releasing the bighead carp fingerlings cultivated in the freshwater pond into the target saline-alkali lake or saline-alkali marsh, the bighead carp fingerlings are first released into a low-alkali pond water body for adaptive domestication, wherein the alkalinity value of the low-alkali pond water body is 1 / 3 to 1 / 2 of the maximum alkalinity value of the saline-alkali water aquaculture in step S1;

[0025] Step S3:

[0026] After the bighead carp fingerlings are domesticated in the low-alkali pond water in step S2 for 5 to 7 days, they are fished out of the pond and put into the target saline-alkali lake or saline-alkali marsh for breeding.

[0027] Beneficial effects of this embodiment:

[0028] (1) This embodiment calculates the median lethal concentration of bighead carp within 12 to 96 hours based on the mortality rate of bighead carp in water bodies with different alkalinity values ​​within 12 to 96 hours, and determines the maximum alkalinity value of bighead carp in saline-alkali water according to experimental results and production experience. Then, the target saline-alkali lakes, marshes and other water bodies suitable for bighead carp aquaculture are screened and determined, avoiding the problem of low survival rate of fish due to high alkalinity of the water body, which causes the fish to be easily killed due to stress.

[0029] (2) This embodiment utilizes target saline-alkali lakes, marshes and other water bodies to prepare low-alkali pond water with a concentration of 1 / 3 to 1 / 2 of the maximum alkalinity value for saline-alkali water aquaculture of bighead carp fingerlings. Through the adaptive domestication of the fish bodies, the stress resistance of the fish bodies can be enhanced, and the stress response of fish fingerlings cultivated in freshwater ponds directly placed in medium- and high-salinity water bodies can be reduced.

[0030] (3) In this embodiment, after the fish species are catching from the freshwater pond, they are released into the low-alkali pond water body for adaptive training for 5 to 7 days, and then released into the target saline-alkali lakes, marshes and other water bodies for aquaculture. This can significantly improve the survival rate of fish species aquacultured in medium- and high-salinity water bodies.

[0031] Specific implementation method 2: The difference between this implementation method and specific implementation method 1 is that in step S1, when the bighead carp grows to a weight of 100-750 g, the mortality rate of the bighead carp in water bodies with different alkalinity values ​​within 12-96 hours is measured.

[0032] The other steps are the same as those in the first specific implementation.

[0033] Specific implementation method three: The difference between this implementation method and specific implementation method one or two is that when the mortality rate of bighead carp in water bodies with different alkalinity values ​​within 12 to 96 hours is determined in step S1, the water temperature is 20 to 23°C.

[0034] The other steps are the same as those in the first or second embodiment.

[0035] Specific implementation method 4: The difference between this implementation method and specific implementation methods 1 to 3 is that in step S1, the safe concentration value of bighead carp within 12 to 96 hours is also calculated, and the safe concentration value is 1 to 17.72 mmol / L.

[0036] The other steps are the same as those in Specific Embodiments 1 to 3.

[0037] Specific embodiment 5: The difference between this embodiment and specific embodiments 1 to 4 is that the median lethal concentration of bighead carp in step S1 is 57.761-89.668 mmol / L.

[0038] The other steps are the same as those in Specific Embodiments 1 to 4.

[0039] Specific implementation method 6: The difference between this implementation method and specific implementation methods 1 to 5 is that the alkalinity of the low-alkali pond water body described in step S2 is 10.0-15.0 mmol / L.

[0040] The other steps are the same as those in Specific Embodiments 1 to 5.

[0041] The following examples are used to verify the beneficial effects of the present invention:

[0042] Embodiment 1: A method for improving the survival rate of bighead carp in saline-alkali water culture, comprising the following steps:

[0043] Step S1: From May to September, one-year-old bighead carp fingerlings are cultivated in a freshwater pond according to conventional artificial breeding techniques and methods for bulk freshwater fish;

[0044] Step S2: In late September, when the bighead carp grows to a weight of 117 g at age 1, chemical analysis grade NaHCO 3 Prepare water with alkalinity of 40mmol / L, 55mmol / L, 70mmol / L, 85mmol / L and 100mmol / L;

[0045] Step S3: 5 to 10 normal and healthy bighead carp fingerlings were collected respectively, and an experiment on the alkalinity tolerance of one-year-old bighead carp fingerlings was carried out through three parallel tests:

[0046] Step S4: Observe and count the high alkali resistance mortality of the experimental fish in each concentration group at different time periods of 12h, 24h, 48h and 96h (see Table 1), and calculate the average fish weight of 117g and the water temperature of 20-23°C by the Guan method commonly used in biotoxicology experiments. The median lethal alkalinity of the experimental fish at 96h is 57.7mmol / L (see Table 2);

[0047] Table 1 shows the mortality experiment of bighead carp 1-year-old fish in different periods of tolerance to alkalinity;

[0048] Table 1

[0049]

[0050] The process of calculating the half-lethal concentration (LC50) by SPSS27.00:

[0051] Take 96h LC50 as an example:

[0052] 1. If Figure 3 As shown, switch to "Variable View" in the lower left corner to define the variables, enter "Dose", "Number of Fish" and "Number of Deaths" after the name, and then switch to "Data View" in the lower left corner to enter data according to the table header.

[0053] 2. If Figure 3 As shown, select "Analysis" → "Regression" → "Probability" in the main menu, call out the "Probability Analysis" dialog box, select "Number of deaths" in the "Response frequency (S)" column, select "Number of fish" in the "Total number of measured values ​​(T)" column, select "Dose" in the "Covariate (C)" column, select "Logarithm with base 10" in the conversion column, keep the other default options, and then click "OK" to output the data.

[0054] 3. If Figure 4 As shown, find the "Confidence Limit" in the output table, and the column with a probability of 0.500 is LC50.

[0055] Table 2 shows the median lethal concentration and safe concentration for one-year-old bighead carp;

[0056] Table 2

[0057]

[0058] Step S5: Based on experimental data and production experience, it is determined that the maximum water alkalinity value of target saline-alkali lakes, marshes, etc. for aquaculture should not exceed 28.0 mmol / L.

[0059] In biology, in acute toxicological tolerance experiments on animals, the safety concentration value and the median lethal concentration value are routinely measured within 96 hours. The safety concentration is the concentration of the toxicant that will not produce adverse effects after long-term exposure, while the median lethal concentration value refers to the concentration of the toxicant that causes half of the test animals to die.

[0060] In saline-alkali water aquaculture, in order to expand the aquaculture space of fisheries, the salinity and alkali concentration of the water body in which fish are stocked during production is generally greater than the safe concentration value and less than the half-lethal concentration value of 96 hours. From a large amount of production experience and experimental data, it is concluded that when the maximum alkalinity value of fish aquaculture in saline-alkali water does not exceed 1 / 2 of the half-lethal concentration value of the fish in 96 hours, fish deaths will basically not occur and they can grow normally. For example, the half-lethal concentration value of alkalinity of silver crucian carp in 96 hours is 64.19mmol / L. In actual production, it should be no problem if the alkalinity of aquaculture water does not exceed 32mmol / L.

[0061] Therefore, based on the above experimental data and production experience, the maximum water alkalinity value for bighead carp to be cultured in saline-alkali water should not exceed 1 / 2 of the 96-hour half-lethal concentration, that is, the maximum alkalinity should not exceed 28.0mmol / L, which is a water alkalinity environment suitable for the culture of bighead carp.

[0062] Step S6: configuring fish adaptive breeding ponds around saline-alkali lakes, marshes, etc., using river water and saline-alkali water bodies targeted for aquaculture to prepare low-alkali aquaculture water bodies with a concentration of 10.0 to 15.0 mmol / L;

[0063] Step S7: After the fish species cultivated in the freshwater pond are caught in September-October, they are first put into low-alkali aquaculture ponds for adaptive domestication for 5-7 days, and then put into saline-alkali lakes, marshes and other water bodies targeted for aquaculture;

[0064] Step S8: Experiments have shown that fish species cultured in freshwater ponds that have not been domesticated will edema (e.g., Figure 1 After 5 days of adaptation to 15mmol / L low-alkaline water, the intestinal tract was normal when sampled 24 hours later, and no edema occurred in the intestinal tissue (as shown in Figure 2). Figure 2 (shown)

[0065] Step S9: In high-salinity water with an alkalinity of 50mmol / L, fish species were directly released without adaptive domestication, and the survival rate after 96 hours was 60%; after adaptive domestication in low-alkaline water for 5 days, after 96 hours, the survival rate of alkalinity 15mmol / L was 100%, the survival rate of alkalinity 20mmol / L was 90%, the survival rate of alkalinity 30mmol / L was 50%, and the survival rate of alkalinity 40mmol / L was 50% (see Table 3).

[0066] Table 3 shows the survival rate of one-year-old bighead carp after adaptation and domestication in low-alkaline water;

[0067] Table 3

[0068]

Claims

1. A method for improving the survival rate of bighead carp in saline-alkali water aquaculture, characterized in that The method proceeds as follows: Step S1: Cultivate the bighead carp fry bred in spring in a freshwater pond, and in autumn or the spring of the second year, when the bighead carp fingerlings grow to 1 to 2 years old, measure the mortality rate of the bighead carp fingerlings in water bodies with different alkalinity values ​​within 12 to 96 hours, and then calculate the median lethal concentration value of the bighead carp fingerlings within 12 to 96 hours based on the mortality rate, and use 1 / 2 of the median lethal concentration value as the maximum alkalinity value for the aquaculture of bighead carp fingerlings in saline-alkali water; Step S2: Before releasing the bighead carp fingerlings cultivated in the freshwater pond into the target saline-alkali lake or saline-alkali marsh, the bighead carp fingerlings are first released into a low-alkali pond water body for adaptive domestication, wherein the alkalinity value of the low-alkali pond water body is 1 / 3 to 1 / 2 of the maximum alkalinity value of the saline-alkali water aquaculture in step S1; Step S3: After the bighead carp fingerlings are domesticated in the low-alkali pond water in step S2 for 5 to 7 days, they are fished out of the pond and put into the target saline-alkali lake or saline-alkali marsh for breeding.

2. A method for improving the survival rate of bighead carp in saline-alkali water aquaculture according to claim 1, characterized in that In step S1, when the bighead carp fingerlings grow to a weight of 100 to 750 g, the mortality rate of the bighead carp fingerlings in water bodies with different alkalinity values ​​within 12 to 96 hours is measured.

3. A method for improving the survival rate of bighead carp in saline-alkali water aquaculture according to claim 1 or 2, characterized in that When determining the mortality rate of bighead carp in water bodies with different alkalinity values ​​within 12 to 96 hours in step S1, the water temperature is 20 to 23°C.

4. A method for improving the survival rate of bighead carp in saline-alkali water culture according to claim 1, characterized in that In step S1, the safe concentration value of bighead carp within 12 to 96 hours is calculated, and the safe concentration value is 1 to 17.72 mmol / L.

5. A method for improving the survival rate of bighead carp in saline-alkali water culture according to claim 1, characterized in that The median lethal concentration of bighead carp in step S1 is 57.761-89.668 mmol / L.

6. A method for improving the survival rate of bighead carp in saline-alkali water culture according to claim 1, characterized in that The alkalinity of the low-alkali pond water in step S2 is 10.0-15.0 mmol / L.

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