Double marking method for trachidermus fasciatus

Abstract

The invention relates to a double marking method for trachidermus fasciatus. The double marking method comprises a strontium marking method and a metal wire code marking method. Through dual marking of the strontium mark and the metal wire code, errors possibly existing in a traditional single marking method can be effectively avoided, and the marking reliability is improved; strontium marks can record inhabitation conditions of fishes in different environments, metal wire codes provide unique identity information of individuals, and the method is suitable for long-term research. According to the method, the persistence and the data management efficiency which are lacked in a previous marking mode are improved.

Description

Technical Field

[0001] The invention belongs to the technical field of aquaculture, and particularly relates to a double marking method for Songjiang perch. Background Art

[0002] Songjiang perch (Trachidermus fasciatus) belongs to the order Scorpaeniformes and the family Cottidae. It is a small downstream migratory fish and a second-level aquatic animal under key protection in my country. In order to better protect the population resources of Songjiang perch, my country has implemented resource compensation measures for many years of reproduction and release. Among them, scientific evaluation of the release effect is an important part of the release of Songjiang perch. Marked release is the most commonly used method to evaluate the effect of reproduction and release, and it is also a key technology for identifying released populations.

[0003] At present, the main method for marking released fish in China is single marking, that is, only physical marking (T-marking, fin clipping, etc.) or chemical marking (strontium marking, fluorescent dye marking, etc.) is used. Physical marking may cause mechanical damage to fish, easily cause inflammatory reactions, and even lead to death. Chemical marking can usually only provide specific information and is easily affected by environmental factors. Therefore, it is very necessary to explore a dual marking method for Songjiang perch. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a double-marking method for Songjiang perch, which can effectively avoid the errors that may exist in the traditional single-marking method and improve the reliability of marking.

[0005] The present invention provides a double labeling method for Songjiang perch, comprising the following steps:

[0006] (1) Strontium marking was performed on the Songjiang perch fry that had been implanted with metal wire codes: strontium solution was prepared in advance, and the fry were placed in a plastic bucket containing the strontium solution, aerated for 24 hours, and 50% of the water was changed every 2 days; during the strontium marking period, the strontium concentration of the water was regularly tested, and aquaculture water with a corresponding strontium concentration was added in time to maintain the strontium concentration of the water, and the marking lasted for a total of 7 days;

[0007] (2) Transfer the strontium-labeled Songjiang perch fry to the breeding pond and maintain the water temperature at 18-22°C and the dissolved oxygen content at 5-8 mg / L. After 3 days of breeding, check the fry to ensure that all fry are in good condition and undamaged before releasing them.

[0008] Preferably, the average body length of the Songjiang perch fry in step (1) is 7-9 cm, and the body weight is 8-10 g.

[0009] Preferably, the strontium solution in step (1) is prepared using SrCl2·6H2O; the concentration of the strontium solution is 12-72 mg / L.

[0010] Preferably, the density of fry in the plastic barrel in step (1) is 30 fry / barrel.

[0011] Beneficial Effects

[0012] The present invention can effectively avoid the errors that may exist in the traditional single marking method through double marking of strontium tags and metal wire codes, and improve the reliability of marking; the strontium tags can record the habitats of fish in different environments, and the metal wire codes provide unique identity information of individuals, which is suitable for long-term research; the present invention provides durability and data management efficiency that are lacking in previous marking methods. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 The data are the number of survivals of Songjiang perch in each concentration group during the marking period and the number of deaths 30 days after marking.

[0014] Figure 2 These are the results of quantitative linear analysis of otoliths of Songjiang perch in the 0-72 mg / L SrCl2·6H2O concentration group. DETAILED DESCRIPTION

[0015] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall within the scope limited by the appended claims of the application equally.

[0016] Example 1

[0017] 1. The first step: metal wire code marking

[0018] 1. Individual Selection

[0019] The juvenile Songjiang perch were selected, with an average body length of 7-9 cm and a body weight of 8-10 g.

[0020] 2. Anesthesia

[0021] MS-222 is the most commonly used anesthetic for anesthetizing Songjiang perch. Songjiang perch can enter the anesthesia period when the mass concentration is 60mg / L. Prepare 1000mg / L MS-222 solution before anesthesia. Temporarily keep Songjiang perch seedlings in a 40L plastic box, add the prepared MS-222 solution to the plastic box to make its mass concentration reach 60mg / L, and wait until the Songjiang perch is anesthetized until the fish body swings regularly and the breathing rate slows down before proceeding to the next step.

[0022] 3. Labeling Experiment

[0023] The anesthetized Songjiang perch were transferred from the plastic box to a flat surface covered with a wet towel to keep the fish skin moist. The wire tag was injected into the thicker part of the back muscle of the Songjiang perch juveniles using a MKIV automatic marking syringe. The wire tag (CWT) is a section of magnetized stainless steel wire with a diameter of 0.25mm. Several rows of numbers are engraved on the marking line to indicate a batch or single code. The double-marked Songjiang perch were transferred to clean water. After 24 hours of observation, it was found that the Songjiang perch juveniles had good body characteristics, the scales at the injection site did not fall off, and the survival rate was 100%.

[0024] 2. Second step strontium labeling example

[0025] The labeling experiment was conducted in 20 300L cylindrical barrels. According to the corresponding dose of SrCl2·H2O, the pond aquaculture freshwater in the barrel was added to make the mass concentration reach 0, 12, 18, 36, and 72 mg / L, respectively, with a total of 5 gradients. Robust and lively, uninjured in appearance, and juvenile fish of similar size were randomly selected and put into the barrels, with 30 fish in each barrel. During the experiment, the feed was a palatable marine fish mixed with pellet feed, and 50% of the water was changed every 2 days. In addition, the labeling group was added with aquaculture water with a corresponding strontium concentration to maintain the strontium concentration. The experiment was labeled for a total of 7 days. After the labeling was completed, each treatment group was continued to raise the strontium concentration in the aquaculture water to restore it to normal levels. The sampling time was 1, 3, 5, 7 days and 7, 14, 28, and 60 days after the labeling was completed. Three fish were sampled each time, and the sampling site was the otolith for otolith element analysis.

[0026] 1. Comparison of growth and mortality of Songjiang perch in different concentration groups

[0027] On the 7th day of immersion marking, 7 experimental fish from each concentration group were extracted to measure body length and weight. It was found that the average body weight and average fatness of the 36 mg / L concentration group reached the maximum value, which were 8.0 g and 1.71 g / cm, respectively, while the average body weight and average fatness of the control group were the smallest, which were 7.7 g and 1.45 g / cm, respectively (Table 1). Through one-way analysis of variance and Duncan multiple comparisons, the average body length, average body weight and average fatness of each group were not significantly different from those of the control group (P>0.05).

[0028] Table 1 Growth changes of Songjiang perch during the marking period

[0029] Concentration Group Average weight Average body length Average fatness 0 <![CDATA[7.7±1.92 a ]]> <![CDATA[8.18±1.11 a ]]> <![CDATA[1.45±0.28 a ]]> 12 <![CDATA[7.9±1.66 a ]]> <![CDATA[8.09±0.99 a ]]> <![CDATA[1.60±0.19 a <!-- 2 -->]]> 18 <![CDATA[7.9±2.57 a ]]> <![CDATA[7.94±0.69 a ]]> <![CDATA[1.63±0.22 a ]]> 36 <![CDATA[8.0±1.93 a ]]> <![CDATA[8.05±1.13 a ]]> <![CDATA[1.71±0.12 a ]]> 72 <![CDATA[8.0±2.05 a ]]> <![CDATA[8.23±1.14 a ]]> <![CDATA[1.49±0.22 a ]]>

[0030] Note: Data with different lowercase letters indicate significant differences (P<0.05).

[0031] During the immersion marking period, the average mortality rates of the 0, 12, 18, 36, and 72 mg / L test groups were all low, namely 3.34%, 0%, 3.34%, 0%, and 0%, respectively. Figure 1 The mortality rate of the 0 and 18 mg / L test groups was the highest, both at 3.34%, while no mortality occurred in the 12, 36 and 72 mg / L concentration groups. After 30 days of labeling, the average mortality rates of the 0, 12, 18, 36 and 72 mg / L concentration groups were 50%, 37%, 33%, 10% and 6.67%, respectively. Figure 1 The mortality rate of the control group was the highest, while that of the 72 mg / L concentration group was the lowest. 2 The test showed that there was no significant effect on the mortality rate of each experimental group (P>0.05), and strontium labeling of otoliths of Songjiang perch was safe.

[0032] 2. Sr / Ca values ​​of Songjiang perch otolith quantitative analysis in different concentration groups

[0033] After 7 days of immersion in water with different concentrations of strontium, the Sr / Ca values ​​of different concentration groups showed different degrees of increase. Among them, the 12 and 18 mg / L concentration groups did not increase at 7 days, but the Sr / Ca value increased at 14, 28, and 60 days, although the increase was not obvious. Through the significance analysis of the Sr / Ca values ​​before and after labeling, the peak mean of the Sr / Ca value increase stage at 60 days of labeling was 1.90±0.56 and 1.95±0.72, which was significantly different from the Sr / Ca value of 0.82±0.27 before the increase (P<0.05), but there was no significant difference with the Sr / Ca value in the 0-0.25 mm segment (P>0.05). This shows that the 12 and 18 mg / L concentration groups have poor strontium labeling effects on Songjiang perch otoliths.

[0034] As the strontium concentration increases, the Sr / Ca value gradually increases, and the 36 and 72 mg / L concentration groups have obvious increasing stages within 7, 14, 30, and 60 days. In particular, in the 72 mg / L concentration group, a clear upward trend was observed on the third day of labeling, and the Sr / Ca values ​​of the 36 and 72 mg / L concentration groups were significantly different from those of the control group and the pre-labeling section (P<0.05). The test results show that immersion in strontium concentrations of 12 to 72 mg / L can produce labeling for all samples, and all samples labeled with high concentrations of 36 and 72 mg / L can form a significant strontium labeling effect, with a labeling rate of 100%.

[0035] 3. Feasibility and stability of otolith strontium labeling

[0036] The experimental data show that ( Figure 2 ), no mortality occurred in the high-concentration group during the labeling period, indicating that immersion in strontium concentrations of 0 to 72 mg / L is safe and reliable for Songjiang perch.

[0037] Moreover, under the immersion of exogenous strontium, the fatness of Songjiang perch in each experimental group was higher than that in the control group within 7 days of labeling, which shows that the appropriate addition of strontium may have a certain promoting effect on the growth of Songjiang perch. In this experiment, all samples in the 36 and 72 mg / L concentration groups can form a good strontium labeling effect, and the labeling rate reaches 100%, which proves its stability and reliability.

[0038] 4. Otolith strontium labeling concentration and time

[0039] Higher strontium concentrations may lead to confusion in short-term strontium and calcium deposition, making the otolith Sr / Ca value unstable. Therefore, considering the impact of labeling recovery time, a strontium concentration of 36 mg / L was used for otolith strontium labeling.

[0040] Considering the labeling effect, labeling cost, metabolic residue and other factors, the optimal concentration of strontium for labeling Songjiang perch otoliths in the present invention is 36 mg / L and the continuous immersion time is 7 days.

[0041] 3. Step 3 Dual Labeling Recovery and Evaluation

[0042] The double-tagged Songjiang perch are released into the Yangtze River estuary and then recaptured using traditional fishing gear. The recaptured Songjiang perch are first inspected for simple line code markings to confirm whether they are tagged fish. If they are confirmed to be tagged fish, further verification of the gill markings is carried out.

[0043] 60 days after release, the juvenile Songjiang perch recaptured in the Yangtze River estuary were 12 cm long and weighed 13 g. The recaptured Songjiang perch had intact body characteristics, stable life, and had adapted to survival in the wild water after release. Scanning with a metal coding scanner found that the recaptured Songjiang perch belonged to the batch released 60 days ago, indicating that they did not migrate long distances after release, but were active in the release waters or nearby areas. The Songjiang perch was dissected and the otoliths were removed, and the Sr / Ca ratio of the otolith samples was analyzed by inductively coupled plasma mass spectrometry (ICP-MS). The results showed that the average Sr / Ca ratio of the otoliths of the recaptured Songjiang perch was about 1.85, which was similar to the ratio of 72 mg / L in the experimental group, labeled for 60 days, indicating that during the growth of the Songjiang perch after release, the ratio of newly deposited strontium to calcium in the otoliths may match its growth rate and metabolic activity, keeping the Sr / Ca ratio relatively constant.

[0044] The dual labeling method of the present invention can effectively improve the accuracy of the evaluation of the release effect of Songjiang perch, and provide technical support for the resource protection and scientific management of Songjiang perch. The method has the advantages of simple operation, efficient data management, strong labeling durability, etc., and is suitable for long-term ecological research and fishery resource monitoring.

Claims

1. A double labeling method for Songjiang perch, comprising the following steps: (1) Strontium marking was performed on the Songjiang perch fry that had been implanted with metal wire codes: strontium solution was prepared in advance, and the fry were placed in a plastic bucket containing the strontium solution, aerated for 24 hours, and 50% of the water was changed every 2 days; during the strontium marking period, the strontium concentration of the water was regularly tested, and aquaculture water with a corresponding strontium concentration was added in time to maintain the strontium concentration of the water, and the marking lasted for a total of 7 days; (2) Transfer the strontium-labeled Songjiang perch fry to the breeding pond and maintain the water temperature at 18-22°C and the dissolved oxygen content at 5-8 mg / L. After 3 days of breeding, check the fry to ensure that all fry are in good condition and undamaged before releasing them.

2. The double labeling method of Songjiang perch according to claim 1, characterized in that: The average body length of the Songjiang perch fry in step (1) is 7-9 cm, and the body weight is 8-10 g.

3. The double labeling method of Songjiang perch according to claim 1, characterized in that: The strontium solution in step (1) is prepared using SrCl2·6H2O; the concentration of the strontium solution is 12-72 mg / L.

4. The double labeling method of Songjiang perch according to claim 1, characterized in that: The density of the fry in the plastic bucket in step (1) is 30 fry / bucket.

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