Reservoir ecological scheduling target object screening method for fishes producing viscous eggs in reservoir area

Abstract

The invention discloses a reservoir ecological scheduling target object screening method for fishes producing viscous and demersal eggs in a reservoir area, and belongs to the field of ecology. The method comprises the following steps: acquiring the species composition, resource information and reproduction habit characteristic information of fishes laying visco-demersal eggs in a reservoir area; determining a first evaluation result of each class in the class composition information according to the first evaluation information, the class composition information, the resource information and the reproduction habit characteristic information; performing correlation analysis on the first evaluation information according to the first evaluation result to obtain second evaluation information; according to the second evaluation information and the first evaluation result of each class in the class composition information, obtaining a second evaluation result of each class in the class composition information; and according to the second evaluation result, determining a reservoir ecological scheduling target object aiming at the fishes producing the viscous demersal eggs in the reservoir area. Through the scheme, an ecological scheduling scheme can be formulated in a targeted manner, so that the method plays a positive role in alleviating adverse effects on reservoir scheduling operation and guaranteeing natural breeding of target fishes in a reservoir area.

Description

Technical Field

[0001] The invention belongs to the field of ecology, and in particular relates to a method for screening reservoir ecological dispatching target objects for fish species that lay sticky and sinking eggs in a reservoir area. Background Art

[0002] The operation of reservoirs has changed the hydrological situation in the reservoir area, which will have an adverse impact on the natural reproduction of fish that lay sticky eggs in the reservoir area. Therefore, it is urgent to implement ecological operation to mitigate the adverse effects of changes in the reservoir hydrological situation on the natural reproduction of fish that lay sticky eggs in the reservoir area.

[0003] Since fish species are different, their ecological habits will be different, the hydrological conditions required for natural reproduction will also be different, and the degree to which they are affected by scheduling operations will also vary. Therefore, it is necessary to first scientifically screen out the main target objects of scheduling in order to implement ecological scheduling in a targeted manner and thus ensure the implementation effect.

[0004] At present, there is still a lack of corresponding technical methods for how to screen and determine the target objects of reservoir ecological scheduling for fish with different breeding habits. Summary of the invention

[0005] In order to solve the problems existing in the prior art, the present invention provides a method for screening reservoir ecological scheduling target objects for fish species that lay sticky and sinking eggs in a reservoir area, the method comprising:

[0006] Obtain information on species, resources and reproductive habits of fish species that lay viscous eggs in the reservoir area;

[0007] Determining a first evaluation result of each category in the category composition information according to the first evaluation information, category information, resource information and breeding habit characteristic information;

[0008] performing a correlation analysis on the first evaluation information according to the first evaluation results of the various categories in the category composition information to obtain second evaluation information, wherein the number of evaluation parameters included in the second evaluation information is less than the number of evaluation parameters included in the first evaluation information;

[0009] Obtaining a second evaluation result for each category in the category composition information according to the second evaluation information and the first evaluation result for each category in the category composition information;

[0010] The target object of reservoir ecological dispatch for fish species that lay sticky eggs in the reservoir area is determined according to the second evaluation results of various species in the species composition information.

[0011] Preferably, the determining of the reservoir ecological dispatch target object for fish species laying sticky and sinking eggs in the reservoir area according to the second evaluation results of various species in the species composition information includes:

[0012] Obtaining a first sorting result of ecological scheduling demand according to a second evaluation result of each category in the category composition information and a first preset sorting method;

[0013] According to the first sorting result of ecological dispatching demand and the second preset sorting method, the target object of reservoir ecological dispatching for fish species laying sticky eggs in the reservoir area is obtained.

[0014] Preferably, the breeding habit characteristic information includes: spawning substrate requirement information, spawning water flow velocity preference information, spawning water depth preference information, spawning ground distribution information, and main spawning month information;

[0015] The species information includes: species composition of fish species that lay viscous and sinking eggs in the reservoir area, species specificity information, endangered degree information and germplasm resource value information;

[0016] The resource information is information on the current status of resource abundance.

[0017] Preferably, the evaluation parameters included in the first evaluation information correspond to the information included in the species information, resource information and breeding habit characteristic information.

[0018] Preferably, the second evaluation information includes evaluation parameters such as: spawning substrate requirement information, spawning water depth preference information, spawning ground distribution information, main spawning month information, endangered degree information, endemicity information, germplasm resource value information, and resource abundance status information.

[0019] Preferably, after determining the reservoir ecological dispatch target object for the fish species producing sticky and sinking eggs in the reservoir area according to the second evaluation results of the various species in the species composition information, it also includes:

[0020] According to the ecological habits of the target fish, the target objects of reservoir ecological scheduling for the fish that lay sticky eggs in the reservoir area are divided into quiet and slow-flow spawning target fish and flowing water spawning target fish. The distribution information of the spawning grounds of the corresponding target fish after the dam is built is determined according to the quiet and slow-flow spawning target fish and flowing water spawning target fish, and the target river section for ecological scheduling is determined based on the distribution information.

[0021] Preferably, after determining the reservoir ecological dispatch target object for fish species that lay sticky and sinking eggs in the reservoir area according to the second evaluation results of various species in the species composition information, the method further comprises:

[0022] Reservoir dispatching information of the target fish species for spawning in the static and slow flow and the target fish species for spawning in the flowing water are determined respectively, wherein the reservoir dispatching information includes: dispatching starting water temperature, dispatching hydrological parameters with suitable flow and suitable daily water level fluctuation, and dispatching duration, and the target fish species for spawning in the static and slow flow and the target fish species for spawning in the flowing water are ecological dispatching target fish species;

[0023] The process of determining the scheduling starting water temperature includes:

[0024] Determine the natural reproduction time of the ecological scheduling target fish and the distribution range of suitable water temperature required by the ecological scheduling target fish according to literature data, artificial breeding information and water temperature information of the reproduction time related to the ecological scheduling target fish, and determine the scheduling starting water temperature according to the suitable water temperature range;

[0025] The process of obtaining the appropriate flow rate includes:

[0026] Based on the habitat suitability model or the flow rate requirement of the spawning ground, the suitability of the habitat of the target fish spawning ground of ecological scheduling is analyzed to obtain the suitable flow rate;

[0027] The process of determining the appropriate daily water level fluctuation includes:

[0028] Determine the suitable daily water level fluctuation range according to the suitable water depth and water level fluctuation range during the breeding period of the ecological scheduling target fish;

[0029] The process of determining the scheduling duration includes:

[0030] According to literature data related to the ecological scheduling target fish, as well as artificial breeding information or on-site hatching test information, the hatching time required for the eggs of the ecological scheduling target fish to hatch to the level swimming period is analyzed, and the scheduling duration is determined based on the hatching time.

[0031] Preferably, the method further comprises: performing reservoir ecological dispatching according to the reservoir dispatching information;

[0032] Reservoir ecological regulation according to the reservoir regulation information includes:

[0033] Determining whether the reservoir dispatching information meets the reservoir implementation feasibility requirement information;

[0034] If the feasibility requirements for reservoir implementation are met, an ecological scheduling plan is determined based on the reservoir scheduling information, and the reservoir ecological scheduling is carried out according to the ecological scheduling plan.

[0035] Preferably, the reservoir implementation feasibility requirement information includes: flood control requirement information for cities downstream of the reservoir, reservoir flood control safety requirement information, minimum downstream flow information, and basic water balance information.

[0036] The beneficial effects brought by this embodiment are as follows:

[0037] By obtaining the species composition, resource information and breeding habit characteristic information of fish species laying sticky eggs in the reservoir area; determining the first evaluation result of each category in the species composition information according to the first evaluation information, the species composition information, the resource information and the breeding habit characteristic information; obtaining the second evaluation information by performing a correlation analysis on the first evaluation information according to the first evaluation result; obtaining the second evaluation result of each category in the species composition information according to the second evaluation information and the first evaluation result of each category in the species composition information; determining the target object of reservoir ecological dispatching for fish species laying sticky eggs in the reservoir area according to the second evaluation result, so as to provide a reliable basis for formulating a reservoir ecological dispatching plan to promote the natural reproduction of fish species laying sticky eggs in the reservoir area in a targeted manner. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 A schematic flow chart of a method for screening reservoir ecological scheduling target objects for fish species that lay sticky and sinking eggs in a reservoir area provided by an embodiment of the present invention;

[0039] Figure 2 The top 15 fish species (without considering weight) in terms of the cumulative scores of ecological dispatching demand of fish species laying sticky and sinking eggs in the Three Gorges Reservoir area provided by the embodiment of the present invention;

[0040] Figure 3 The top 30 species with cumulative scores of ecological dispatching demand for fish with sticky and sinking eggs in the Three Gorges Reservoir area and their cumulative scores (taking weights into account) provided in the embodiment of the present invention;

[0041] Figure 4 A statistical distribution diagram of a difference significance test of the cluster grouping of the top 30 categories with cumulative scores provided in an embodiment of the present invention;

[0042] Figure 5 A clustering grouping diagram of the top 30 categories with cumulative scores provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0043] To make the objectives, technical solutions and advantages of the present invention more clear, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0044] See also Figure 1 The embodiment of the present invention provides a method for screening reservoir ecological scheduling target objects for fish that lay sticky and sinking eggs in the reservoir area, and the method comprises the following steps:

[0045] Step 101, obtaining species information, resource information and breeding habit characteristic information of fish that lay sticky sinking eggs in the reservoir area.

[0046] The process of implementing this step may be: obtaining historical information of fish that lay sticky sinking eggs in the reservoir area, which is a record of historical survey and research data on the fish resources. By collecting these materials and conducting on-site supplementary monitoring, for example; the results of early fish resource surveys, the species information, resource information and breeding habit characteristics of fish that lay sticky sinking eggs in the reservoir area can be obtained. Species information is used to indicate which species of fish that lay sticky sinking eggs there are in the reservoir area, as well as the species' uniqueness (i.e., uniqueness information), endangered degree information and germplasm resource value information; resource information is resource abundance information. The uniqueness information is used to indicate whether the fish is a fish that is unique to the river where the reservoir area to be studied is located. The resource abundance status information is used to indicate the fish that can be surveyed through fish resources and early fish resources, that is, species of fish with a certain amount of resources.

[0047] The breeding habit characteristic information includes: spawning substrate requirement information, water flow velocity preference information during spawning, spawning water depth preference information, spawning ground distribution information, and main spawning month information. Among them, the spawning substrate requirement information is used to indicate the type of aquatic habitat preferred by fish. Step 102, determine the first evaluation result of each type in the type composition information according to the first evaluation information, type information, resource information, and breeding habit characteristic information.

[0048] The first evaluation information has multiple evaluation parameters, which correspond to the aforementioned species composition information, resource information and breeding habit characteristic information. Specifically: parameters used to represent the spawning habitat requirement characteristics of a certain species (i.e., the evaluation object) in the species composition information. There are 4 parameters of this type, namely: spawning substrate requirements, water flow velocity preference during spawning, spawning water depth preference and spawning ground distribution; parameters used to represent the life history characteristics of a certain species in the species composition information. There is 1 parameter of this type, which is the main spawning month; parameters used to represent the conservation value of a certain species in the species composition information. There are 3 parameters of this type, namely: endangered degree, endemicity, and germplasm resource value; parameters used to represent the resource status of a certain species population in the species composition information. There is 1 parameter of this type, which is the current status of resource abundance.

[0049] It should be noted that the value of germplasm resources can be divided into three categories: high level, medium level and low level. Among them, the high level is used to represent germplasm resource fish, which can be determined in the application through the list of germplasm resource fish and the list of aquatic germplasm resource protection areas. The medium level is used to represent medium and large fish among non-germplasm resource fish. Medium and large fish can refer to species whose individuals above the preset percentage threshold can grow to a preset length or above. The low level is used to represent small fish among non-germplasm resources. Small fish can refer to species whose individuals above the preset percentage threshold cannot grow to a preset length or above. In this embodiment, the preset percentage threshold can be 50%; the preset length can be 25cm.

[0050] The first evaluation information also has: characteristic information corresponding to the evaluation parameters, and the characteristic information includes: hierarchical characteristic values ​​and corresponding weights. In this embodiment, there are four hierarchical characteristic values, namely: first-level characteristic value, second-level characteristic value, third-level characteristic value and fourth-level characteristic value, the first-level characteristic value is less than the second-level characteristic value, the second-level characteristic value is less than the third-level characteristic value, and the third-level characteristic value is less than the fourth-level characteristic value. Some evaluation parameters may correspond to the four hierarchical characteristic values, and some evaluation parameters may correspond to hierarchical characteristic values ​​less than four, which are specifically determined according to the evaluation parameters, and this embodiment does not limit this.

[0051] After determining the first evaluation information, the relevant information of each species in the species composition information can be determined based on the first evaluation information and the resource information and breeding habit characteristic information corresponding to each species in the species composition information. The relevant information includes: species composition information, evaluation parameters, and characteristic information corresponding to the evaluation parameters. Then, based on the relevant information, each species in the species composition information is evaluated, so that the first evaluation result can be determined. Among them, the first evaluation result includes: species composition information, evaluation parameters, and characteristic results corresponding to the evaluation parameters. The characteristic results corresponding to the evaluation parameters can be obtained by processing the characteristic information corresponding to the evaluation parameters, and the processing method can be: multiplying the graded characteristic value and the weight.

[0052] It should be noted that the above evaluation results can usually be determined based on the above historical information and on-site investigation and research information. When a certain type of characteristic information corresponding to a certain evaluation parameter is difficult to determine, it can be determined through expert consultation.

[0053] Step 103: performing correlation analysis on the first evaluation information according to the first evaluation results of the various categories in the category composition information to obtain second evaluation information, wherein the number of evaluation parameters included in the second evaluation information is less than the number of evaluation parameters included in the first evaluation information.

[0054] The characteristic results in the first evaluation results of various categories in the category composition information are standardized, for example, using logarithm for standardization. Then, the correlation analysis method is used to screen the evaluation parameters reflecting the independence of the information, and the evaluation parameters reflecting the redundant information are eliminated to reduce the multicollinearity of different evaluation parameters, so as to obtain the second evaluation information, in which the number of evaluation parameters contained in the second evaluation information is less than the number of evaluation parameters contained in the first evaluation information. The correlation analysis method can select the Pearson correlation analysis method.

[0055] Step 104: obtaining a second evaluation result for each category in the category composition information according to the second evaluation information and the first evaluation result for each category in the category composition information.

[0056] After obtaining the second evaluation information, the second evaluation results of the various categories in the category composition information corresponding to the second evaluation information can be obtained according to the first evaluation results of the various categories in the category composition information. For the implementation of this step, please refer to the relevant description of obtaining the first evaluation result in the above step 102, which will not be repeated here. It should be noted that the second evaluation result for the same category in the category composition information is consistent with the first evaluation result.

[0057] Step 105, determining the reservoir ecological dispatch target object for the fish species that lay sticky eggs in the reservoir area according to the second evaluation results of the various species in the species composition information.

[0058] This step can be implemented by: obtaining a first ranking result of ecological scheduling requirements based on the second evaluation results of various categories in the species composition information and the first preset ranking method; obtaining a reservoir ecological scheduling target object for fish species that lay sticky and sinking eggs in the reservoir area based on the first ranking result of ecological scheduling requirements and the second preset ranking method. It should be noted that the first preset ranking method can be a scoring linear ranking method, and the second preset ranking method can be a scoring hierarchical ranking method.

[0059] Specifically, the target evaluation results of the various categories in the category composition information are obtained according to the second evaluation results of the various categories in the category composition information. The method of obtaining the target evaluation results of the various categories in the category composition information may be: accumulating the characteristic results corresponding to the evaluation parameters in the second evaluation results. Then, the target evaluation results of the various categories are sorted to obtain the first sorting result of the ecological scheduling requirements of the various categories in the category composition information.

[0060] In the first ranking result of ecological scheduling needs, the first target species range in the species composition information is determined according to the first preset condition, and then the matrix data formed by the first evaluation result corresponding to the first target species range is clustered and analyzed to obtain a cluster analysis matrix for characterizing different types of ecological scheduling needs, that is, a cluster grouping result. The cluster grouping result is then grouped using the percentage similarity test (ANOSIM) method, and the final grouping situation, that is, the second ranking result, is determined through inter-group significance.

[0061] In order to facilitate the identification of the ecological scheduling demand level of different fish species, a hypothetical species MAX is set as a reference: MAX is used to represent the species with the highest ecological scheduling demand level, and the graded characteristic values ​​of its various evaluation parameters all achieve the maximum value. It should be noted that: the first preset condition can be a species whose target evaluation result is greater than 80% of the highest target evaluation result, and this implementation does not make specific restrictions on this.

[0062] According to the first sorting result and the second sorting result, the second target species range in the species composition information is determined, which is the target object of reservoir ecological scheduling for fish that lay sticky eggs in the reservoir area. Specifically, species (or species) that are clustered together with MAX species and whose first sorting results meet the second preset condition can be selected as fish species with a high ecological scheduling demand level, and identified as the main target fish for ecological scheduling, that is, the target object. Usually, the ecological scheduling demand level of fish in the same group as MAX is higher than the ecological scheduling demand level of fish in other groups. It should be noted that: the second preset condition can be a species whose target evaluation result is greater than 80% of the highest target evaluation result of the same group, and this implementation does not make specific limitations on this.

[0063] The following takes the Three Gorges Reservoir as an implementation area to explain in detail the implementation process of the method for selecting reservoir ecological dispatching target objects for fish species that lay sticky eggs in the reservoir area:

[0064] Step 1) Obtain the species composition, resource information and breeding habit information of fish species that lay sticky eggs in the reservoir area.

[0065] First, based on the results of the catch survey, habitat survey, and early resource survey conducted in the main and tributary rivers of the Three Gorges Reservoir area from 2019 to 2023, and combined with the existing relevant historical literature, the reproductive ecology data of 87 species of fish that lay sticky eggs and sink in the main and tributary rivers of the Three Gorges Reservoir area were sorted out, and the breeding months, peak breeding time, and preferred spawning substrate types of various fish that lay sticky eggs were clarified. The results are shown in Table 1. In practice, some species have a large span of breeding months, and in this case, the peak breeding time can be used to make judgments.

[0066] Table 1 Information on the reproductive habits of fish species that lay sticky eggs and are currently distributed in the main and tributary rivers of the Three Gorges Reservoir area

[0067]

[0068]

[0069]

[0070]

[0071] It should be noted that: * indicates fish species unique to the upper reaches of the Yangtze River

[0072] Step 2) Determine the preliminary evaluation indicators and their scores and weights for the target objects of reservoir ecological regulation for fish species with viscous and sinking eggs in the reservoir area

[0073] The evaluation candidate indicators (or preliminary indicators or so-called) for the target object of reservoir ecological regulation of fish with sticky eggs in the reservoir area and their scores (corresponding to the aforementioned graded characteristic values) and weights are shown in Table 2. This information corresponds to the first evaluation information.

[0074] Table 2 Alternative indicators and their classification for the screening and evaluation of target fish species for ecological scheduling of the reservoir area that lays sticky and sinking eggs

[0075]

[0076] Step 3) According to the breeding habit characteristic information table and resource information of different types of fish in step 1, and according to the preliminary selected indicators and their scores and weights in step 2), the index values ​​of each type of fish in the reservoir area that lay sticky eggs in Table 2 are analyzed respectively. Some fish have missing data, which are replaced by their closely related species. When the values ​​of some qualitative evaluation indicators of some species are difficult to determine, they are determined through expert consultation method.

[0077] According to Table 2, the original scores of different fish species on each preliminary index were obtained, and the sum of the scores of all preliminary indexes was calculated. The results showed that the total original scores of thick-jawed bream, rock carp and short-bodied loach on each preliminary index ranked in the top three. Figure 2 shown.

[0078] Step 4), after obtaining the score values ​​of different preliminary indicators in step 3), the scores of all preliminary indicators are first standardized using logarithm; then, the Pearson correlation method is used to screen indicators that reflect information independence, and indicators that reflect redundant information are eliminated to reduce multicollinearity of different indicators.

[0079] When conducting Pearson correlation analysis, the spawning ground distribution is taken as the core indicator. When the correlation between other indicators and this indicator is r>0.6, and the significance level p<0.01, this indicator will be eliminated; when the correlation between other indicators and the spawning ground distribution indicator is r<0.6, but the correlation between this indicator and other indicators is r>0.6, and the significance level p<0.01, indicators will be eliminated by comparing the correlation between these indicators and other indicators. Generally, indicators with greater correlation will be eliminated.

[0080] The results of Pearson analysis showed that the correlation between any index and the spawning ground distribution index was not significant, but the water flow velocity preference index during spawning was extremely significantly related to the spawning substrate index (r = 0.621, p = 0.000), and the relationship between this index and the other 8 indicators was also significant. Therefore, after comprehensive consideration, this index was eliminated from the alternative index evaluation system. Finally, there were 8 indicators used to evaluate the ecological scheduling demand level of fish with viscous eggs in the main and tributary river sections of the Three Gorges Reservoir area, namely, spawning substrate index, spawning water depth index, spawning ground distribution index, main spawning month index, endangered degree index, endemicity index, germplasm resource value index and resource abundance status index.

[0081] After eliminating the alternative spawning water velocity preference indicators, we finally obtained the ecological scheduling demand screening index system for fish species laying sticky eggs in the Three Gorges Reservoir area, as shown in Table 3. The information at this time corresponds to the second evaluation information.

[0082] Table 3. Ecological dispatching demand screening index system for fish species laying sticky eggs in the Three Gorges Reservoir area

[0083]

[0084]

[0085] Step 5), after eliminating the indicators reflecting redundant information, the final score of each indicator is calculated based on the original score of each indicator and the weight of each indicator. On this basis, the final score of each indicator is arithmetically summed to obtain a simple cumulative score of the ecological scheduling needs of different fish. Subsequently, the ranking results of the ecological scheduling needs of each species are obtained by sorting the cumulative scores by species. Based on the scoring linear sorting results, the top 30 species with cumulative scores (species with scores of more than 80% of the highest score) are selected for scoring ranking analysis. The cluster analysis method is used to perform cluster analysis on the matrix data of the final scores of each evaluation indicator of these 30 species to obtain a cluster analysis matrix of ecological scheduling needs of different species. In order to facilitate the identification of the ecological scheduling demand level of different fish species, a hypothetical species (MAX) is set as a reference: MAX represents the species with the highest ecological scheduling demand level, and its various evaluation parameters (or evaluation indicators) all achieve the maximum value. For the cluster grouping results, the percentage similarity test (ANOSIM) method is used for grouping test, and the final grouping is determined by the significance between groups.

[0086] The ecological regulation demand evaluation scores of 87 species of fish with viscous eggs in the main and tributary sections of the Three Gorges Reservoir area were calculated. The results showed that the ecological regulation demand evaluation score of the rock carp was the highest, followed by the thick jawed bream, the southern catfish, and the short-bodied loach. Figure 3 .

[0087] The percentage similarity test (ANOSIM) method was used to compare the differences between the clustering grouping results by gradually adding fish species to the MAX grouping, and finally it was determined that the species with the top 30 cumulative scores could be clustered into three groups. The ANOSIM test results are shown in Tables 4 and Figure 4 As shown, the results show that the differences among different groups are significant (between the three groups, global variable R=0.648, p=0.1%; between any two groups, p<0.05), indicating that there are significant differences in the ecological scheduling demand structure information represented by different groups.

[0088] Table 4 Significance test of differences among the clustering groups of the top 30 categories with cumulative scores

[0089]

[0090]

[0091] According to the above analysis, the final cluster analysis results are as follows: Figure 5 The results showed that group 1 included MAX species and 14 fish species, including rock carp, thick jaw bream, short-bodied loach, and red tail loach; group 2 included 12 fish species, including carp, crucian carp, catfish, southern catfish, and long-snout catfish; group 3 included other 4 fish species, namely Chinese redfin mullet, Yangtze sturgeon, wide-mouthed light-lipped fish, and Yunnan light-lipped fish. Group 1 is the fish species with the highest ecological regulation demand level. The fish in this group are all fish species that spawn among the gravels in flowing water. Among them, the rock carp is a national second-level protected animal. The rock carp, thick-jawed bream, Dai's mountain loach, Emei houping loach, Xichang Chinese loach, Sichuan Chinese loach, short-bodied paraloach, Wang's erythroculter and black-tailed erythroculter are endemic to the upper reaches of the Yangtze River; Group 2 fish are mainly fish species that can live and forage in quiet and slow-flow habitats, but spawning must be achieved in flowing water; Group 3 fish are fish species whose spawning grounds are mainly distributed in the backwater river section outside the reservoir area. This group of fish has the lowest ecological regulation demand level in the Three Gorges Reservoir and can be excluded as fish species for the ecological regulation of the reservoir water level.

[0092] Step 6), combining the results of the scoring linear sorting method and the scoring hierarchical sorting method obtained in step 5, select the species that are clustered together with the MAX species and ranked in the front as fish species with high ecological scheduling demand levels, and identify them as the main target fish for ecological scheduling. Generally, the ecological scheduling demand level of fish in the same group as MAX is higher than that of fish in other groups.

[0093] Based on the results of the above two ranking methods (taking into account both the cumulative score and the multi-index structural characteristics), rock carp, thick-jawed bream, long-snout catfish, southern catfish, carp, crucian carp, and catfish were selected from Group 1 and Group 2 with high or relatively high ecological regulation demand levels as representative target fish for water level regulation of the Three Gorges Reservoir. Among them, rock carp, thick-jawed bream, long-snout catfish, and southern catfish are fish species that spawn in flowing gravel beaches, while carp, crucian carp, and catfish are fish that spawn on aquatic grass substrates in quiet and slow-flowing areas. The water level and flow velocity conditions that meet the spawning and hatching conditions of these representative fish will also meet the hydrological habitat needs of fish in similar spawning and hatching habitats during spawning and hatching.

[0094] Step 7) After determining the target object of reservoir ecological regulation for fish that lay sticky eggs in the reservoir area, determine the distribution information of the spawning grounds of the target fish after the dam is built, and determine the target river section of ecological regulation based on the distribution information. According to the living habits of the target fish, they can be divided into: target fish that lay eggs in slow flow and target fish that lay eggs in flowing water.

[0095] According to the results of the ecological scheduling target fish screening, the target fish for scheduling in the slow flow of the Three Gorges Reservoir are carp, crucian carp and catfish. According to the results of early resource surveys, the spawning grounds of carp, crucian carp and catfish are mainly located in the main stream section from Yunyang County to Banan District in Chongqing and in the backwater areas of tributaries such as Xiaojiang River and Modao Creek, where there are more aquatic plants. The target fish for scheduling in the flowing water of the Three Gorges Reservoir are rock carp, thick jaw bream, long snout catfish and southern catfish, and their spawning grounds are mainly distributed in the flowing water gravel beach area in the backwater change area of ​​the Three Gorges Reservoir.

[0096] Step 8) determining the reservoir dispatching information of the target fish species for spawning in static and slow flow and the target fish species for spawning in flowing water, the reservoir dispatching information including: dispatching starting water temperature, dispatching hydrological parameters with suitable flow and suitable daily water level fluctuation, and dispatching duration;

[0097] The process of determining the starting water temperature for scheduling includes:

[0098] According to the literature, artificial breeding information and water temperature information of the target fish species for ecological scheduling, the suitable water temperature range for spawning and hatching of the target fish species (carp, crucian carp and catfish) in slow flow is determined to be 17-23℃; the lower limit water temperature for spawning of southern catfish is 15℃, and the lower limit water temperature for spawning of rock carp, thick jaw bream and long snout catfish is 18℃. The starting water temperature for scheduling is determined according to the suitable water temperature range.

[0099] The process of determining the appropriate flow rate includes:

[0100] According to data research, on-site investigation, etc., the flow velocity of target fish for spawning in flowing water is above 0.7m / s during spawning. A one-dimensional hydrodynamic model is used to simulate the water depth and flow velocity distribution in the downstream area of ​​the backwater change zone. The results show that in order to make most of the river sections in the backwater change zone meet the suitable water level and upstream water conditions for the flow velocity required for spawning and reproduction of four target fish for spawning in flowing water, when the water level at Changshou (II) station is below 160m, the upstream water needs to be between 5000-10000m3 / s; when the water level at Changshou (II) station is between 160-165m, the upstream water needs to be 10000m3 / s and above; when the water level at Changshou (II) station is above 165m, the upstream water needs to be 15000m3 / s and above.

[0101] The process of determining the appropriate daily water level fluctuation includes:

[0102] According to data research, on-site investigations, etc., the spawning depth of carp and crucian carp is 20-80cm, and the suitable spawning depth is 41-60cm; the spawning depth of catfish is 0.18-0.72m, and the suitable spawning depth is 0.3-0.6m. The suitable spawning depths of target fish for flowing water spawning are 0.6-2m for rock carp, 0.3-1m for thick-jawed bream, 0.5-1.4m for southern catfish, and 0.7-1.5m for long-snout catfish. Therefore, for sticky grass spawning fish such as carp, crucian carp, and catfish, the water level should not drop more than 0.8m (preferably not more than 0.6m) during the incubation of their eggs; for flowing gravel spawning fish such as rock carp, thick-jawed bream, and southern catfish, the water level should not drop more than 2m (preferably not more than 1m) during the incubation of their eggs.

[0103] The process of determining the scheduling duration includes:

[0104] According to literature related to the target fish species of ecological scheduling, as well as artificial breeding information or on-site hatching test information, the time from hatching of fertilized eggs to the start of swimming for carp and crucian carp is 4-6 days, for catfish is 3-5 days, for rock carp is 6-8 days, for thick-jawed bream is 5-7 days, for southern catfish is 4-7 days, and for long-snout catfish is 5-8 days. It is determined that the scheduling duration for the target fish species spawning in slow flows (carp, crucian carp and catfish) is 6 days, and the scheduling duration for southern catfish, rock carp, thick-jawed bream and long-snout catfish is 8 days.

[0105] Step 9) Perform reservoir ecological regulation based on reservoir regulation information.

[0106] The implementation process of this step includes the following steps:

[0107] Determine whether the reservoir dispatching information meets the requirements for reservoir implementation feasibility. The difficulty in implementing ecological dispatching to promote the spawning and reproduction of fish with viscous eggs and the survival of early fry in the Three Gorges Reservoir is to maintain the water level drop during the day or within the day during the ecological dispatching period, and how to coordinate the dispatching needs of different reproduction types. According to the water level data of the Miaohe section in front of the dam from 2011 to 2023, the water level drop of 0.8m within 6 days often occurred in each year from mid-April to late May from 2011 to 2023, indicating that it is feasible to maintain the water level drop of 0.8m during the day or within the day during the ecological dispatching of the Three Gorges Reservoir. At the same time, it is also feasible to keep the upstream water inflow of the reservoir above 5000m3 / s from mid-April to late May.

[0108] Therefore, the ecological dispatching plan is determined according to the hydrological dispatching information as follows, and the reservoir ecological dispatching is carried out according to the ecological dispatching plan.

[0109] Phase 1: From mid-April to late April, the water level in front of the dam is maintained at 165m or above. When the water temperature reaches 18℃, ecological regulation is carried out to promote the spawning of fish such as carp, crucian carp and catfish. The duration of ecological regulation is at least 6 days. The total water level drop within 6 days shall not exceed 0.8m (preferably no more than 0.6m); the water level drop within 4 hours in a day shall not exceed 0.8m.

[0110] The second stage: from early to late May, when the water level in front of the dam drops to 155m-160m and the water temperature is above 18℃, ecological regulation of flowing gravel spawning fish such as rock carp, thick jaw bream and long snout catfish will be carried out. The ecological regulation will last at least 8 days. The total water level drop within 8 days shall not exceed 2m (preferably no more than 1m); the water level drop within 4 hours per day shall not exceed 2m; the upstream flow rate shall be above 5000m3 / s.

[0111] It is known from common technical knowledge that the present invention can be implemented by other embodiments that do not deviate from its spirit or essential features. Therefore, the above disclosed embodiments are only illustrative in all respects and are not exclusive. All changes within the scope of the present invention or within the scope equivalent to the present invention are included in the present invention.

Claims

1. A method for screening reservoir ecological scheduling target objects for fish that lay sticky and sinking eggs in the reservoir area, characterized in that: The method includes: Obtain information on species, resources and reproductive habits of fish species that lay viscous eggs in the reservoir area; Determining a first evaluation result of each category in the category composition information according to the first evaluation information, category information, resource information and breeding habit characteristic information; performing a correlation analysis on the first evaluation information according to the first evaluation results of the various categories in the category composition information to obtain second evaluation information, wherein the number of evaluation parameters included in the second evaluation information is less than the number of evaluation parameters included in the first evaluation information; Obtaining second evaluation results for each category in the category composition information according to the second evaluation information and the first evaluation results for each category in the category composition information; The target object of reservoir ecological dispatch for fish species that lay sticky eggs in the reservoir area is determined according to the second evaluation results of various species in the species composition information.

2. The method for selecting reservoir ecological scheduling target objects according to claim 1, characterized in that: The target object of reservoir ecological dispatching for fish species laying sticky and sinking eggs in the reservoir area is determined according to the second evaluation results of various species in the species composition information, including: Obtaining a first sorting result of ecological scheduling demand according to a second evaluation result of each category in the category composition information and a first preset sorting method; According to the first sorting result of ecological dispatching demand and the second preset sorting method, the target object of reservoir ecological dispatching for fish species laying sticky eggs in the reservoir area is obtained.

3. The method for selecting reservoir ecological scheduling target objects according to claim 1, characterized in that: The breeding habit characteristic information includes: spawning substrate requirement information, spawning water flow velocity preference information, spawning water depth preference information, spawning ground distribution information, and main spawning month information; The species information includes: species composition of fish species that lay viscous and sinking eggs in the reservoir area, species specificity information, endangered degree information and germplasm resource value information; The resource information is information on the current status of resource abundance.

4. The method for selecting reservoir ecological regulation target objects according to claim 3 is characterized in that: The evaluation parameters included in the first evaluation information correspond to information included in the species information, resource information, and breeding habit characteristic information.

5. The method for selecting reservoir ecological dispatching target objects according to claim 3, characterized in that: The second evaluation information includes the following evaluation parameters: spawning substrate requirement information, spawning water depth preference information, spawning ground distribution information, main spawning month information, endangered degree information, endemicity information, germplasm resource value information, and resource abundance status information.

6. The method for selecting reservoir ecological dispatching target objects according to claim 1, characterized in that: After determining the reservoir ecological dispatch target object for the fish species producing sticky and sinking eggs in the reservoir area according to the second evaluation results of the various species in the species composition information, it also includes: According to the ecological habits of the target fish, the target objects of reservoir ecological scheduling for the fish that lay sticky eggs in the reservoir area are divided into quiet and slow-flow spawning target fish and flowing water spawning target fish. The distribution information of the spawning grounds of the corresponding target fish after the dam is built is determined according to the quiet and slow-flow spawning target fish and flowing water spawning target fish, and the target river section for ecological scheduling is determined based on the distribution information.

7. The method for selecting reservoir ecological dispatching target objects according to claim 6, characterized in that: After determining the reservoir ecological dispatch target object for the fish species laying sticky and sinking eggs in the reservoir area according to the second evaluation results of the various species in the species composition information, the method further includes: Reservoir dispatching information of the target fish species for spawning in the static and slow flow and the target fish species for spawning in the flowing water are determined respectively, wherein the reservoir dispatching information includes: dispatching starting water temperature, dispatching hydrological parameters with suitable flow and suitable daily water level fluctuation, and dispatching duration, and the target fish species for spawning in the static and slow flow and the target fish species for spawning in the flowing water are ecological dispatching target fish species; The process of determining the scheduling starting water temperature includes: Determine the natural reproduction time of the ecological scheduling target fish and the distribution range of suitable water temperature required by the ecological scheduling target fish according to literature data, artificial breeding information and water temperature information of the reproduction time related to the ecological scheduling target fish, and determine the scheduling starting water temperature according to the suitable water temperature range; The process of obtaining the appropriate flow rate includes: Based on the habitat suitability model or the flow rate requirement of the spawning ground, the suitability of the habitat of the target fish spawning ground of ecological scheduling is analyzed to obtain the suitable flow rate; The process of determining the appropriate daily water level fluctuation includes: Determine the suitable daily water level fluctuation range according to the suitable water depth and water level fluctuation range during the breeding period of the ecological scheduling target fish; The process of determining the scheduling duration includes: According to literature data related to the ecological scheduling target fish, as well as artificial breeding information or on-site hatching test information, the hatching time required for the eggs of the ecological scheduling target fish to hatch to the level swimming period is analyzed, and the scheduling duration is determined based on the hatching time.

8. The method for selecting reservoir ecological dispatching target objects according to claim 7, characterized in that: The method further includes: performing reservoir ecological dispatching according to the reservoir dispatching information; Reservoir ecological regulation according to the reservoir regulation information includes: Determining whether the reservoir dispatching information meets the reservoir implementation feasibility requirement information; If the feasibility requirements for reservoir implementation are met, an ecological scheduling plan is determined based on the reservoir scheduling information, and the reservoir ecological scheduling is carried out according to the ecological scheduling plan.

9. The method for selecting reservoir ecological dispatching target objects according to claim 8, characterized in that: The reservoir implementation feasibility requirement information includes: flood control requirement information for cities downstream of the reservoir, reservoir flood control safety requirement information, minimum downstream flow information, and basic water balance information.

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