Optimal selection method for artificial reefs of redfin snapper juveniles based on behavioral characteristics

Abstract

The present invention discloses a method for optimizing artificial reefs for juvenile redfin snappers based on behavioral characteristics, the method comprising: building a microcosm experimental environment for juvenile redfin snappers and a number of artificial reef structures with different opening shapes and specifications; constructing an artificial reef experimental pool based on the microcosm experimental environment and the artificial reef structures with different opening shapes and specifications; observing and extracting the behavioral characteristics of juvenile redfin snappers in different artificial reef experimental pools, the behavioral characteristics including fear of new things, reef tendency and clustering; taking the behavioral characteristics as the domestication target, screening suitable reef structures. The present invention can screen artificial reef structures suitable for the survival of juvenile redfin snappers according to their behavioral characteristics, thereby improving the release efficiency and survival rate of juvenile redfin snappers.

Description

Technical Field

[0001] The invention relates to the technical field of fishery infrastructure construction, and more particularly to a method for optimizing artificial fish reefs for juvenile redfin snappers based on behavioral characteristics. Background Art

[0002] Enhancement and release is an important measure to conserve fishery resources, protect biodiversity, repair the fishery environment, and increase fishermen's income. With the expansion of the scale of enhancement and release, the problem of low release efficiency has become increasingly prominent. For enhanced and released fish, their behavioral adaptability is poor. After release, the seedlings will inevitably experience a more natural, unpredictable and heterogeneous environment, including intraspecific competition, predator pressure and variable environmental factors, resulting in low release efficiency. These stressors from the water environment are bound to induce a series of behavioral responses to protect their own safety. Therefore, the adaptability of fish to specific situations will ensure their healthy survival in the wild environment. When the unknown environmental pressure exceeds the adaptability of fish, the fish will change the normal behavioral phenotype through stress response, reducing the survival welfare of the fish. Therefore, how to optimize the survival adaptability of fish after release is an important issue to improve the efficiency of enhancement and release.

[0003] Artificial reefs refer to artificial structures set up in the sea to gather fish and other marine life by utilizing the tendencies of fish and other marine life (such as tactile attraction, flow attraction, etc.). They can produce bait effect, flow field effect, shelter effect, environmental change effect, shadow effect, etc. to attract organisms to gather, thereby increasing the biomass of the sea area around the reef area.

[0004] Like most amplified species, the redfin snapper also faces the key problem of low efficiency in amplification and release. In the natural environment, the redfin snapper is a typical reef-dwelling fish with relatively strong behavioral plasticity, but the aquaculture environment of the redfin snapper before release lacks physical structures such as reefs suitable for its survival. Therefore, taking the behavioral plasticity of the redfin snapper as a way, and the differences in habitat characteristics between its natural environment and aquaculture environment as a starting point, the behavioral response of the redfin snapper to artificial reefs after amplification and release is studied through behavioral acclimation, which provides new ideas for improving its adaptability to the wild environment after release.

[0005] In general, there is currently no method to select artificial reef structures suitable for the survival of fish of different sizes based on their behavioral characteristics through behavioral domestication. Summary of the invention

[0006] The current behavior adaptability of released redfin snapper fry is poor, and the fry will inevitably experience a more natural, unpredictable and heterogeneous environment (including intraspecific competition, predator pressure and variable environmental factors) after release, resulting in a lower release efficiency. The present invention provides a method for optimizing artificial reefs for redfin snapper fry based on behavioral characteristics.

[0007] In order to achieve the above object, the present invention adopts the following technical solution:

[0008] The method for selecting artificial reefs for juvenile redfin snapper based on behavioral characteristics comprises the following steps:

[0009] Step 1. Build a microcosm experimental environment for redfin snapper juveniles and several artificial fish reef structures with different opening shapes and specifications;

[0010] Step 2. constructing an artificial fish reef experimental pool based on the microcosm experimental environment and a number of artificial fish reef structures with different opening shapes and specifications;

[0011] Step 3. Observe and extract the behavioral characteristics of redfin snapper juveniles in different artificial reef experimental pools, wherein the behavioral characteristics include novelty fear, reef tendency and clustering;

[0012] Step 4. Using the behavioral characteristics as the training target, select suitable fish reef structures.

[0013] Furthermore, in step 1, a microcosm experimental environment for redfin snapper fry is constructed, which specifically includes the following steps:

[0014] A square water tank with a blue background was selected as a microcosm experimental water tank for juvenile redfin snappers, and the dissolved oxygen concentration, pH value, temperature and salinity indexes in the experimental water tank were monitored and adjusted to meet the experimental environment requirements.

[0015] Furthermore, in step 1, building a plurality of artificial fish reef structures with different opening shapes and specifications specifically includes the following steps:

[0016] A box-shaped structure with a cubic appearance is constructed by splicing acrylic panels as an artificial fish reef structure; openings of different shapes and sizes are arranged on each surface of the box-shaped structure; the different shapes of the openings include diamond, circle and square; the opening size of the opening is designed according to multiples of the body height of redfin snapper fry.

[0017] Furthermore, the opening size of the opening is designed according to the multiple of the body height of the redfin snapper fry, specifically including:

[0018] The opening ratio of the artificial fish reef structure is set to 0.5 times, 1.0 times, 1.5 times and 2 times the body height of the redfin snapper fry in sequence, and the opening ratio is a multiple of the body height of the redfin snapper fry.

[0019] Further, in step 3, the behavioral characteristics of redfin snapper juveniles in different artificial reef experimental pools are observed and extracted, which specifically includes the following steps:

[0020] Several redfin snapper juveniles with the same number of tails were randomly selected and placed in different artificial reef experimental pools;

[0021] Use high-definition cameras to collect real-time video data on the behavior of redfin snapper juveniles in different artificial reef experimental tanks;

[0022] Every 30 minutes, 30 seconds of behavioral video data were intercepted for statistical analysis to obtain behavioral index data, including first reef contact time, average distribution rate, average speed, average turning angle, average moving distance, percentage of active time, nearest neighbor fish distance and average neighbor fish distance;

[0023] The behavioral characteristics of redfin snapper fry are obtained according to the behavioral index data.

[0024] Furthermore, according to the behavioral index data, the behavioral characteristics of the redfin snapper fry are obtained, specifically including:

[0025] Determining the neophobia of juvenile redfin snapper based on the time of first reef contact;

[0026] The reef tendency of redfin snapper juveniles was determined based on the average distribution rate;

[0027] The sociality of redfin snapper juveniles was determined based on the nearest neighbor distance and the average neighbor distance.

[0028] The swimming activity of redfin snapper juveniles was determined based on average speed, average turning angle, average distance moved, and percentage of active time.

[0029] Furthermore, in step 4, the behavioral characteristics are used as the domestication target to screen suitable fish reef structures, which specifically includes the following methods:

[0030] Single target behavior selection:

[0031] When the target behavior is neophobia, the artificial reef structure corresponding to the shortest time for the first contact of redfin snapper juveniles with the reef is selected;

[0032] When the target behavior is reef-seeking, the artificial reef structure with the largest reef-seeking parameter of redfin snapper juveniles is selected;

[0033] When the target behavior is clustering, the artificial reef structure corresponding to the minimum sum of the nearest neighbor distance and the average neighbor distance of redfin snapper juveniles is selected;

[0034] Multi-objective behavior selection:

[0035] When the target behaviors are novelty fear and reef seeking,

[0036] When both novelty fear and reef attraction are the target behaviors, the artificial reef structure with the smallest value of W = T-10Y is selected;

[0037] When both novelty fear and swarming are the target behaviors, the artificial reef structure with the minimum value of W = T + D is selected;

[0038] When reef-seeking and clustering are the target behaviors at the same time, the artificial reef structure with the smallest value of W = D-20Y is selected;

[0039] When novelty-phobia, reef-taxis and swarming are the target behaviors at the same time, the artificial reef structure with the smallest value of W = T + D - 50Y is selected;

[0040] Where W represents the value of artificial fish reef structure selection, T represents the value of novelty fear parameter, Y represents the value of reef tendency parameter, and D represents the value of clustering parameter.

[0041] Furthermore, the reef tendency parameter is obtained by the following measurement formula:

[0042] Y = 0.65A + 0.3B + 0.05C;

[0043] Where Y represents the reef-tending parameter value, A is the average distribution rate of the fish reef area, B is the average distribution rate of the fish reef radiation area, C is the average distribution rate of the distant reef area, and 0.65, 0.3 and 0.05 are the weight coefficients of the fish reef area, fish reef radiation area and distant reef area respectively.

[0044] Furthermore, before step 3, the following steps are also included:

[0045] The redfin snapper fry are placed in a temporary holding pond for temporary holding.

[0046] Furthermore, the temporary holding pond is a square structure and is equipped with a biological filtration pump, which is used to filter the aquaculture seawater; the temporary holding pond is aerated 24 hours a day, and the aquaculture pond is maintained, monitored, water is changed and cleaned every week.

[0047] It can be seen from the above technical solutions that, compared with the prior art, the present invention discloses a method for optimizing artificial reefs for juvenile redfin snapper based on behavioral characteristics, which has the following beneficial effects:

[0048] The present invention can select an artificial fish reef structure suitable for the survival of redfin snapper fry according to their behavioral characteristics, thereby improving the release efficiency and survival rate of redfin snapper fry;

[0049] The present invention proposes for the first time to set the opening size of the artificial fish reef according to the body height of the redfin snapper fry, so as to determine the optimal artificial fish reef structure according to the body height of the fish;

[0050] The present invention proposes for the first time to determine reef-taxis parameters under regional division conditions, thereby improving the accuracy of the reef-taxis parameters of juvenile redfin snappers. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0052] Figure 1 The present invention provides a flow chart of the method.

[0053] Figure 2 Schematic diagram of the structure of artificial fish reefs with different opening shapes provided by the present invention, wherein Figure 2 A represents an artificial reef structure with a circular opening shape. Figure 2 B represents an artificial fish reef structure with a square opening shape. Figure 2 C represents an artificial fish reef structure with a diamond-shaped opening.

[0054] Figure 3 A schematic diagram of the area division of the artificial fish reef experimental pool provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0055] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0056] The embodiment of the present invention discloses a method for optimizing artificial reefs for juvenile redfin snapper based on behavioral characteristics, comprising the following steps:

[0057] Step 1. Build a microcosm experimental environment for redfin snapper juveniles and several artificial fish reef structures with different opening shapes and specifications;

[0058] Step 2. constructing an artificial fish reef experimental pool based on the microcosm experimental environment and a number of artificial fish reef structures with different opening shapes and specifications;

[0059] Step 3. Observe and extract the behavioral characteristics of redfin snapper juveniles in different artificial reef experimental pools, wherein the behavioral characteristics include novelty fear, reef tendency and clustering;

[0060] Step 4. Use behavioral characteristics as the training target and select suitable fish reef structures.

[0061] The inventive steps of the present invention are described in detail below. Figure 1 As shown, the present invention firstly needs to build a microcosm experimental environment for juvenile redfin snappers and an artificial fish reef structure, and construct an artificial fish reef experimental pool.

[0062] In this embodiment, the microcosm test tank for redfin snapper juveniles was a square tank with a blue background of 260 cm × 230 cm × 100 cm and a water depth of 60 cm. During the experiment, water conditions, dissolved oxygen concentration (mg / L), pH, temperature (°C), and salinity were measured every day using a multi-parameter device (YSI, Professional Plus, Yellow Springs, Ohio, USA). During the experiment, the flowing seawater was turned off, and no aeration or feeding was performed.

[0063] like Figure 2 As shown in the figure, the artificial reef structure is a box-shaped artificial reef, which is made up of 6 identical acrylic plates, with specifications of 30cm×30cm×30cm (length×width×height), and the thickness of each plate is 0.5cm. Each side of the artificial reef includes 9 openings, which are circular ( Figure 2 A), square ( Figure 2 B) and rhombus ( Figure 2 C). The size of the opening is designed according to the multiple of the body height of the test fish. In the study, 500 redfin snapper fry were intact individuals, with a total length of 5.4±0.8cm, a body length of 4.3±0.7cm, a body height of 1.9±0.2cm, and a body weight of 4.1±0.9g. In the experiment, the body height of the redfin snapper fry was about 2.0cm, so the diameters of the openings in the artificial reefs were set to 1.0cm, 2.0cm, 3.0cm and 4.0cm, respectively, that is, the opening ratios were 0.5 times, 1.0 times, 1.5 times and 2 times the body height of the experimental fish, respectively. There are 12 types of artificial reef reef structure models used in this embodiment.

[0064] like Figure 3 As shown, the method of dividing the artificial fish reef experimental pool area is that the dark color in the middle marks the location of the fish reef model, the area surrounding the fish reef and the internal area of ​​the fish reef are divided into the fish reef area (Area A), the area surrounding the reef area is the fish reef radiation area (Area B), and the edge and four corner areas of the experimental pool are the far reef area (Area C).

[0065] Before each experiment, 10 fish were randomly selected from the temporary holding pond and placed in the experimental pond for behavioral observation.

[0066] In a specific embodiment, the temporary holding pond has a size of 200cm×120cm×80cm (length×width×height), and is equipped with pumps for mechanical and biological filtration to filter the aquaculture seawater. The aquaculture pond is maintained, monitored, water is changed (1 / 3 of the total volume) and cleaned weekly. The seawater temperature used for temporary holding and experiment is 28.1±0.4℃, the salinity is 33.0‰, the pH value is 8.42±0.14, the dissolved oxygen is maintained at more than 6mg / L, and the temporary holding pond is aerated for 24h. The feeding method is artificial feeding, 50g is put in at 9:00 and 17:00 every day, and the uneaten bait and excrement are cleaned by siphoning method 0.5h after feeding.

[0067] The artificial reef test pool can be set up to conduct experiments simultaneously, or it can be set up to be one to save costs. When there is only one artificial reef test pool, in order to avoid the test fish from having an adaptive response to the tank environment and the reef model, the next batch of 10 fish will be replaced after each experiment. At the same time, in order to prevent chemical signals from being left in the water, all the water will be replaced after each experiment.

[0068] The experiment was set up in 13 groups, each group repeated the experiment three times, each group had 10 fish, a total of 390 fish, of which 12 groups were placed Figure 2 There was one artificial reef for each of the 12 types of artificial reefs, and the 13th group was the control group, with no reef structure placed in the experimental pool. In order to test the adaptability of the fish to the wild environment after release, the experiment began filming immediately after the fish were placed in the experimental pool. The filming time for each group was 8:00-18:00, and the filming time was 10 hours.

[0069] In all experiments, the behavior of individuals was analyzed indirectly, without the interference of the presence of an observer, by visualizing videos recorded by webcams. All videos were analyzed by a single observation software or human observer, which ensured that the criteria for defining the behavior of redfin snapper were the same throughout the analysis. The behavioral data of redfin snapper were obtained by behavioral video analysis.

[0070] Due to the analysis requirements, it is necessary to capture videos with higher resolution as much as possible. The tracking system uses two-dimensional video, and three individuals are selected for behavioral tracking analysis based on contrast and background subtraction to obtain behavioral data. In all experimental processes, individual behaviors are analyzed indirectly without the interference of other observers.

[0071] Based on the behavioral data, the corresponding behavioral indicators and behavioral characteristics were calculated and extracted. The behavioral indicators include the first time of reef contact, average distribution rate, average speed, average turning angle, average moving distance, percentage of active time, nearest neighbor fish distance and average neighbor fish distance. The first time of reef contact indicates the time taken by the experimental fish to approach the artificial reef for the first time, which is used to illustrate the fear behavior characteristics of fish to new things, that is, neophobia; the average distribution rate indicates the percentage of distribution time of the experimental fish in the reef area, the reef radiation area and the distant reef area, which is used to illustrate the reef-seeking behavior characteristics of fish; the average speed, average turning angle, average moving distance and percentage of active time are used to illustrate the swimming ability of fish; the nearest neighbor fish distance and the average neighbor fish distance indicate the clustering behavior characteristics of fish.

[0072] According to the living habits of fish, target behaviors that need to be domesticated are selected purposefully, including behaviors with novelty phobia, reef tendency or clustering characteristics as domestication targets. The optimal value of this behavior is used as the standard, and then the fish reef structure information under corresponding conditions is obtained. Among them, in the single-target behavior selection, when the target behavior is novelty phobia, the reef selection condition is the reef structure corresponding to the condition that the experimental fish's first contact with the reef time T is the shortest; when the target behavior is reef-seeking, the reef selection condition is the reef structure corresponding to the condition that the artificial reef reef-seeking parameter of the experimental fish is the largest. Therefore, this study proposed for the first time the artificial reef reef-seeking parameter Y under the conditions of the experimental area division, and its measurement formula is Y=0.65A+0.3B+0.05C, where A is the average distribution rate of the reef area, B is the average distribution rate of the reef radiation area, and C is the average distribution rate of the distant reef area. 0.65, 0.3 and 0.05 are the weight coefficients of the reef area, the reef radiation area and the distant reef area respectively; when the target behavior is clustering, the reef selection condition is the condition that the experimental fish's nearest neighbor fish distance (dd) and the average neighbor fish distance (dm) are the smallest, that is, the reef structure corresponding to the minimum D=dd+dm. In the multi-target behavior selection, when neophobia and reef-seeking are the target behaviors, the selection condition is the reef structure with a smaller value of W=T-10Y; when neophobia and clustering are the target behaviors, the selection condition is the reef structure with a smaller value of W=T+D; when reef-seeking and clustering are the target behaviors, the selection condition is the reef structure with a smaller value of W=D-20Y; when neophobia, reef-seeking and clustering are the target behaviors, the selection condition is the reef structure with a smaller value of W=T+D-50Y. The specific methods are shown in Table 1:

[0073] Table 1 Screening method of artificial reef structure based on behavioral characteristics

[0074] Target Behavior Screening principles Neophobia (T) Tminimum Reef-seeking (Y) Maximum Y value Clustering (D) D minimum Noxophobia (T) + reef-seeking (Y) W = T-10Y, minimum Neophobia (T) + Clustering (D) W=T+D, minimum value Reef-seeking (Y) + gregariousness (D) W=D-20Y, minimum Noxophobia (T) + reef-seeking (Y) + gregariousness (D) W=T+D-50Y, minimum value

[0075] Based on the fish reef structure index screening method, according to the characteristic behavior of fish domestication, the optimal fish reef structure index under the corresponding target conditions is selected to further construct a suitable artificial fish reef structure.

[0076] The following is a brief description of the experimental calculation and analysis of behavioral data based on the behavioral characteristics of redfin snapper juveniles.

[0077] Noxious behavior: There was no significant difference in the time when the experimental fish first contacted the reef under different reef opening ratios and opening shapes (t test), but in the diamond model test group, the experimental fish were the most adventurous, with an average time of 245.88s for the first contact with the reef, followed by the circular model test group, with a response time of 513.25s, and the slowest response time was 783s in the square model test group. The novelty-phobic behavior of the experimental fish was negatively correlated with the final average distribution rate of the reef area. The shorter the initial exploration time, the higher the average distribution rate in the reef model area.

[0078] Reef-seeking behavior: In the control group, the average distribution rate of redfin snapper juveniles in each area of ​​the experimental pool was not significantly different (P>0.05). The average distribution rate of redfin snapper juveniles in each area was 71.15% in the far reef area, followed by 18.69% in the reef radiation area, and the minimum was 10.16% in the reef area. The average distribution rate was far reef area > reef radiation area > reef area. The distribution of redfin snapper juveniles was mainly around the pool, and they rarely went to the reef area, but there was no significant difference in the average distribution rate.

[0079] After placing the artificial reef model in the experimental pool, the average distribution rate of redfin snapper juveniles in each area of ​​the experimental pool was significantly different (P < 0.05), and the average distribution rate of redfin snapper juveniles in the fish reef area was also significantly different (P < 0.05). The artificial reef model has a significant effect on attracting redfin snapper juveniles. Under the conditions of circular and square openings, the average distribution rate of redfin snapper juveniles in the fish reef area was significantly different under different opening ratios (P < 0.05), while under the condition of diamond openings, the average distribution rate of redfin snapper juveniles in the fish reef was significantly different under the conditions of opening ratios of 1.0 times, 1.5 times and 2.0 times (P < 0.05), and there was no significant difference under the condition of opening ratio of 0.5 times. Among them, under the artificial reef structure with circular openings and opening ratio of 2.0 times, the average distribution rate of redfin snapper juveniles in the fish reef area was the highest, which was 26.69%, and the attracting effect was the best. In the artificial reef structure with a circular opening shape and an opening ratio of 0.5 times, the average distribution rate of redfin snapper fry in the reef was the lowest, at 12.33%.

[0080] The two-way ANOVA analysis of the attracting effects of artificial reefs with different structures on juvenile redfin snapper is shown in Table 2. The opening ratio of the artificial reefs had a significant effect on the average distribution rate of juvenile redfin snapper (P < 0.05), while the opening shape of the artificial reefs and the interaction between the two had no significant effect on the average distribution rate of juvenile redfin snapper (P > 0.05).

[0081] Table 2 Effects of opening ratios and shapes of different artificial reefs on the average distribution rate of redfin snapper juveniles

[0082]

[0083] In the average distribution rate of the reef area, there was no significant difference in the three artificial reef models with different opening shapes, and the redfin snapper juveniles had no obvious selectivity for the opening shape of the reef. For the four artificial reefs with different opening ratios, the average distribution rate of the redfin snapper juveniles in the reef area was significantly different (P < 0.05), and the order of the opening ratio corresponding to the average distribution rate from large to small was 2.0 times > 1.0 times > 1.5 times > 0.5 times.

[0084] Clustering behavior: There were significant differences in the average speeds of redfin snappers in different treatment groups (P<0.05). The average speed in the control group was 40.30±9.28cm / s. After the addition of artificial reefs, the average speed decreased significantly, as low as 20.93±3.57cm / s. The average speed in the reef with a square opening shape and an opening ratio of 0.5 times was the highest, which was 31.09±4.24cm / s, and the average speed in the reef with a diamond opening shape and an opening ratio of 1.0 times was the lowest, which was 7.94±5.21cm / s.

[0085] There was a significant difference in the average turning angles among the different treatment groups (P<0.001). In the control group, the average turning speed of redfin snapper was the lowest, 30.64±5.88deg / s. After adding artificial reefs, the average turning angle increased significantly, 51.60±8.69deg / s. The average turning angle of the reef with a circular opening shape and a ratio of 1.0 times was the highest, 66.23±9.41deg / s, and the average turning angle of the reef with a circular opening shape and a ratio of 0.5 times was the lowest, 36.83±4.20deg / s.

[0086] The average movement distance of 30s measured in different treatment groups was significantly different (P<0.05). In the control group, the total movement distance of redfin snapper was the highest, which was 1207.07±281.62cm. After adding artificial reefs, the total movement distance was significantly reduced to 624.21±108.80cm. The average movement distance of the reef with a square opening shape and a ratio of 0.5 times was the highest, which was 925.99±124.46cm, and the average movement distance of the reef with a diamond opening shape and a ratio of 1.0 times was the lowest, which was 238.24±156.39cm.

[0087] There were extremely significant differences in the percentage of active time among different treatment groups (P<0.001). In the control group, the percentage of active time of redfin snapper was the highest, 86.90±11.39%. After adding artificial reefs, the percentage of active time decreased significantly, 57.92±21.39%. The percentage of active time in the reef with a circular opening shape and a ratio of 2.0 times was the highest, 79.39±15.63%, and the percentage of active time in the reef with a circular opening shape and a ratio of 1.0 times was the lowest, 30.76±18.32%.

[0088] There were extremely significant differences in the distances between the nearest neighbor fish in different treatment groups (P<0.001), which was 23.82±11.01cm in the control group, the highest distance of nearest neighbor fish in the reef with a square opening shape and a ratio of 0.5 times, which was 32.10±13.36cm, and the lowest distance of nearest neighbor fish in the reef with a circular opening shape and a ratio of 1.0 times, which was 21.38±8.35cm. There were extremely significant differences in the average inter-individual distances in different treatment groups (P<0.001), which was 83.57±32.20cm in the control group, the highest average inter-individual distance in the reef with a square opening shape and a ratio of 1.0 times, which was 105.04±21.43cm, and the lowest average inter-individual distance in the reef with a circular opening shape and a ratio of 1.5 times, which was 66.41±17.95cm.

[0089] This embodiment is based on reef-tending as the behavioral domestication goal before proliferation and release. According to the research results of reef-tending behavioral indicators and behavioral characteristics, the study found that there was no significant difference in the reef-tending of the three artificial reef structures with opening shapes, but the opening ratio significantly affected the reef-tending characteristics, among which the order of opening ratios from strong to weak reef-tending was 2.0 times>1.0 times>1.5 times>0.5 times. Among the three opening shapes in this embodiment, under the artificial reef structure with a circular opening shape and an opening ratio of 2.0 times, the average distribution rate of redfin snapper fry in the reef area was the highest at 26.69%, and the attracting effect was the best, indicating that its reef-tending behavior was the strongest. Therefore, for the reef-tending domestication process of redfin snapper, the artificial reef structure with a circular opening shape and an opening ratio of 2.0 times is the preferred artificial reef structure.

[0090] The present invention illustrates the behavioral characteristics of juvenile redfin snappers with a body length of about 4 cm in an artificial fish reef environment by using an example, and proposes an optimal fish reef structure obtained by a method for optimizing the structure of an artificial fish reef for taming, multiplying and releasing juvenile redfin snappers using behavioral characteristics analysis. However, the present invention is not limited to the described embodiments, and those skilled in the art may also make equivalent variations and substitutions of fish species, body lengths and fish reef structures without violating the spirit of the present invention. These equivalent variations and substitutions are all included in the scope defined by the claims of this application.

[0091] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0092] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for optimizing artificial reefs for juvenile redfin snapper based on behavioral characteristics, characterized in that: include: Step 1. Build a microcosm experimental environment for redfin snapper juveniles and several artificial fish reef structures with different opening shapes and specifications; Step 2. Based on the microcosm experimental environment and several artificial fish reef structures with different opening shapes and specifications, an artificial fish reef experimental pool is constructed; Step 3. Observe and extract the behavioral characteristics of redfin snapper juveniles in different artificial reef experimental pools, including novelty fear, reef attraction and clustering; Randomly select a number of redfin snapper juveniles of the same number and place them in different artificial reef experimental pools; collect behavioral video data of juveniles in different artificial reef experimental pools; obtain behavioral index data through statistical analysis, including first reef contact time, average distribution rate, average speed, average turning angle, average moving distance, percentage of active time, nearest neighbor fish distance and average neighbor fish distance; obtain the behavioral characteristics of redfin snapper juveniles based on the behavioral index data; The novelty fear of redfin snapper juveniles was determined based on the time of first reef contact; the reef tendency of redfin snapper juveniles was determined based on the average distribution rate; the clustering nature of redfin snapper juveniles was determined based on the nearest neighbor fish distance and the average neighbor fish distance; the swimming activity of redfin snapper juveniles was determined based on the average speed, average turning angle, average moving distance and percentage of active time; Step 4. Use behavioral characteristics as the training target to select suitable reef structures; Among them, the single target behavior selection: when the target behavior is neophobia, the artificial reef structure corresponding to the shortest time of first contact with the fish reef by the juvenile redfin snapper is selected; when the target behavior is reef-taxis, the artificial reef structure with the largest reef-taxis parameter of the juvenile redfin snapper is selected; when the target behavior is clustering, the artificial reef structure corresponding to the minimum sum of the nearest neighbor fish distance and the average neighbor fish distance of the juvenile redfin snapper is selected.

2. The method for optimizing artificial reefs for young redfin snapper based on behavioral characteristics according to claim 1, characterized in that: In step 1, the microcosm experimental environment for redfin snapper juveniles is constructed, which specifically includes the following steps: A square water tank with a blue background was selected as a microcosm experimental water tank for juvenile redfin snappers, and the dissolved oxygen concentration, pH value, temperature and salinity indexes in the experimental water tank were monitored and adjusted to meet the experimental environment requirements.

3. The method for optimizing artificial reefs for juvenile redfin snapper based on behavioral characteristics according to claim 1, characterized in that: In step 1, a plurality of artificial reef structures with different opening shapes and specifications are constructed, which specifically includes the following steps: A box-shaped structure with a cubic appearance is constructed by splicing acrylic panels as an artificial fish reef structure; openings of different shapes and sizes are arranged on each surface of the box-shaped structure; the different shapes of the openings include diamond, circle and square; the opening size of the opening is designed according to multiples of the body height of redfin snapper fry.

4. The method for optimizing artificial reefs for juvenile redfin snapper based on behavioral characteristics according to claim 3, characterized in that: The opening size of the opening is designed according to the multiples of the body height of the redfin snapper fry, specifically including: The opening ratio of the artificial fish reef structure is set to 0.5 times, 1.0 times, 1.5 times and 2 times the body height of the redfin snapper fry in sequence, and the opening ratio is a multiple of the body height of the redfin snapper fry.

5. The method for optimizing artificial reefs for juvenile redfin snapper based on behavioral characteristics according to claim 1, characterized in that: In step 4, the behavioral characteristics are used as the domestication target to screen suitable reef structures, specifically including the following methods: Multi-target behavior selection: When the target behaviors are novelty fear and reef seeking, When both novelty fear and reef attraction are the target behaviors, the artificial reef structure with the smallest value of W = T-10Y is selected; When both novelty fear and swarming are the target behaviors, the artificial reef structure with the minimum value of W = T + D is selected; When reef-seeking and clustering are the target behaviors at the same time, the artificial reef structure with the smallest value of W = D-20Y is selected; When novelty-phobia, reef-taxis and swarming are the target behaviors at the same time, the artificial reef structure with the smallest value of W = T + D - 50Y is selected; Where W represents the value of artificial fish reef structure selection, T represents the value of novelty fear parameter, Y represents the value of reef tendency parameter, and D represents the value of clustering parameter.

6. The method for optimizing artificial reefs for young redfin snapper based on behavioral characteristics according to claim 5, characterized in that: The reef tendency parameter is obtained by the following measurement formula: Y = 0.65A + 0.3B + 0.05C; Where Y represents the reef-tending parameter value, A is the average distribution rate of the fish reef area, B is the average distribution rate of the fish reef radiation area, C is the average distribution rate of the distant reef area, and 0.65, 0.3 and 0.05 are the weight coefficients of the fish reef area, fish reef radiation area and distant reef area respectively.

7. The method for optimizing artificial reefs for juvenile redfin snapper based on behavioral characteristics according to claim 6, characterized in that: Before step 3, there are also steps: The redfin snapper fry are placed in a temporary holding pond for temporary holding.

8. The method for optimizing artificial reefs for young redfin snapper based on behavioral characteristics according to claim 7, characterized in that: The temporary holding pond is of square structure and equipped with a biological filtration pump, which is used to filter the aquaculture seawater; the temporary holding pond is aerated 24 hours a day, and the aquaculture pond is maintained, monitored, water is changed and cleaned every week.

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