A method for assessing the ecological health of estuarine fisheries and its application

Abstract

The present invention provides an estuarine fishery ecological health assessment method and application, belonging to the field of ecological assessment. The method divides the research object of estuarine fishery ecological health assessment into biological groups according to the trophic level of the whole food chain. The divided single biological groups are phytoplankton, zooplankton, benthic animals and fish. Then, data is obtained by collecting, preserving, identifying species and biological determination of samples in the estuary to be assessed, which is used to construct the biological integrity index of the single biological group, and then the weight of each single biological group is calculated for comprehensive evaluation. The method of the present invention solves the singleness and one-sidedness of the evaluation of single biological groups, reduces the deviation of the evaluation, and makes the evaluation more scientific and reasonable. The weight of each biological group is calculated by the average trophic level, which not only provides a new idea and method for quantitative calculation of weights, but also improves the accuracy of weights, and solves the subjective influence of the value assignment method, expert scoring method and other methods in determining weights.

Description

Technical Field

[0001] The invention belongs to the field of ecological assessment, and specifically relates to an estuarine fishery ecological health assessment method and application. Background Art

[0002] The estuary ecosystem is located at the intersection of the river and the marine ecosystem. It is the main channel for the exchange of materials between the river basin and the ocean, and has the characteristics of both river and marine ecosystems. Due to its superior geographical and environmental conditions, the estuary is also a densely populated and economically developed area. With economic development and irrational human activities, coupled with the impact of climate change, estuaries have generally shown a trend of resource degradation, environmental deterioration and intensified disasters, and the ecological environment has suffered serious damage. The health of the estuary ecosystem has become one of the important factors restricting the sustainable development of the social economy in the estuary area.

[0003] Ecosystem health is a new science developed in the late 1980s, which is formed by the intersection and integration of natural science, social science and health science. In 1989, Rapport first discussed the connotation of ecosystem health. He believed that "ecosystem health refers to the ability of the ecosystem to maintain its organizational structure, self-regulation and resilience to stress over time"; Costanza defined ecosystem health from the ecosystem itself - no disease, stability or resilience, diversity or complexity, vitality or growth space, and automatic balance between the system and its elements. In recent years, ecosystem health assessment has become a research hotspot for domestic scholars.

[0004] There are two main methods for evaluating the health of estuarine ecosystems: the indicator species method and the indicator system method. The indicator species method selects key species of the ecosystem or species that indicate environmental changes to evaluate the health of the ecosystem. The indicator system method is a comprehensive evaluation of various types of information at various organizational levels of the ecosystem under the premise of selecting groups at different organizational levels and considering different scales.

[0005] The Index of Biological Integrity (IBI) was proposed by Karr in 1981 as a water pollution index to evaluate the quality of the water environment. The index system has since developed into various forms. Among them, the IBI system with 12 indicators (including species structure, nutritional structure, quantity and physical condition) revised by Fausch et al. has been widely used. IBI is currently a widely used indicator in the health assessment of aquatic ecosystems. Commonly used ones include the fish integrity index (F-IBI), benthic animal integrity index (B-IBI), and plankton integrity index (P-IBI). The essence of these single-group biological integrity index evaluations is to measure the health of the water ecology from the perspective of a certain type of biological cluster. Although it is more comprehensive than the evaluation method based on a single organism, it cannot fully describe the integrity of the ecosystem, and the evaluation results of IBIs of different groups often show inconsistency. Summary of the invention

[0006] Aiming at the defects of single-group biological integrity index evaluation, the present invention constructs a multi-group biological integrity ecological health assessment method based on the concept that "a good aquatic ecological environment must have a perfect ecological community structure", taking phytoplankton, zooplankton, benthic animals and fish as research objects, covering the whole food chain (web) from "primary producers (phytoplankton) - secondary producers (zooplankton) - advanced consumers (fishery organisms)", and integrating the characteristics of various groups of organisms, solving the singleness and one-sidedness of single biological group evaluation, reducing the deviation of evaluation, and making the evaluation more scientific and reasonable. The weight of each biological group is calculated by the average trophic level, which not only provides a new idea and method for quantitative calculation of weights, but also improves the accuracy of weights, and solves the subjective influence of weight determination by assignment method, expert scoring method, etc.

[0007] The present invention is achieved through the following technical solutions:

[0008] One of the technical solutions of the present invention is to provide an estuarine fishery ecological health assessment method, which divides the research object of estuarine fishery ecological health assessment into biological groups according to the trophic levels of the whole food chain. The divided single biological groups are phytoplankton, zooplankton, benthic animals and fish. Then, data are obtained by collecting, preserving, identifying species and biologically determining samples in the estuary to be assessed, which is used to construct a biological integrity index of the single biological group, and then the weight of each single biological group is calculated for comprehensive evaluation.

[0009] As one of the preferred embodiments, the method for calculating the weight of each single biological group is to calculate it by the average trophic level of each biological group:

[0010] Step 1: Phytoplankton is taken as primary productivity, and its trophic level is set as 1; zooplankton is taken as secondary productivity, and its trophic level is set as 2; the average trophic level of benthic animals and fish is calculated by combining the trophic level of species with the resource density, all calculated according to the following formula:

[0011]

[0012] Where: MTL is the average trophic level of the fish / benthic animal community; D i is the relative abundance of the ith fish / benthic animal; TL i is the trophic level of the ith fish / benthic animal.

[0013] The second step is to calculate the weight according to the following formula:

[0014]

[0015] Where: W i is the weight of the i-th biological group, MTL i is the average trophic level of the ith biological group.

[0016] As one of the preferred implementation schemes, the comprehensive evaluation of fishery ecological health: based on the weight of each biological group and the total score of IBI, the comprehensive value of fishery ecological health is calculated, and the evaluation is performed according to the health grade evaluation standard (Table 2);

[0017] CEI=(P-IBI)*W P +(Z-IBI)*W Z +(B-IBI)*W B +(F-IBI)*W F (5)

[0018] Where: CEI is the comprehensive value of fishery ecological health; P-IBI is the phytoplankton integrity index value, W P is the phytoplankton weight; Z-IBI is the zooplankton integrity index value, W Z is the zooplankton weight; B-IBI is the benthic animal integrity index value, W B is the benthic animal weight; F-IBI is the fish integrity index value, W F Weighting of fish;

[0019] Table 2 Health level standards

[0020]

[0021] As one of the preferred embodiments, the method for constructing the biological integrity index of a single biological group is as follows:

[0022] ①Determine candidate indicators ②Determine reference points ③Screen indicators through discriminant ability analysis and correlation analysis ④Calculate IBI and evaluate ecological status of each site ⑤Calculate the total IBI score.

[0023] The second technical solution of the present invention is to provide an application of managing estuarine ecology using the estuarine fishery ecological health assessment method.

[0024] The beneficial effects of the present invention compared with the prior art are as follows:

[0025] Based on the biological groups of the entire food chain of "primary producers-secondary producers-higher consumers", the present invention constructs a multi-group biological integrity ecological health assessment method, which solves the singleness and one-sidedness of the assessment of a single biological group. For the first time, the average trophic level method is adopted to integrate the trophic level of species and the amount of resources to calculate the weight of each biological group, which not only provides a new idea and method for the quantitative calculation of weights, but also improves the accuracy of the weights. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 A flow chart of an estuarine fishery ecological health assessment method of the present invention;

[0027] Figure 2 To provide a distribution map of marine survey stations;

[0028] Figure 3 This is a box plot of the biological indicators at the reference point and damaged point after the initial screening in May;

[0029] Figure 4 This is the box plot of the biological indicators at the reference point and damaged point after the initial screening in July;

[0030] Figure 5 Box plot of biological indicators at reference points and damaged points after preliminary screening in December. DETAILED DESCRIPTION

[0031] The technical solution of the present invention is further explained below by way of embodiments, but the protection scope of the present invention is not limited in any form by the embodiments.

[0032] Example 1

[0033] A method for assessing the ecological health of an estuarine fishery is disclosed. The method divides the research object of the ecological health assessment of an estuarine fishery into biological groups according to the trophic levels of the entire food chain. The divided single biological groups are phytoplankton, zooplankton, benthic animals and fish. Then, data are obtained by collecting, preserving, identifying species and conducting biological measurements of samples in the estuary to be assessed, which are used to construct a biological integrity index of the single biological group. The weight of each single biological group is then calculated for a comprehensive evaluation, such as Figure 1 shown.

[0034] 1. Calculation of single biological group integrity index

[0035] Phytoplankton, zooplankton and benthic animals all use the same sampling points as reference points, and the method and steps for calculating the BI are the same. However, the historical data are used as reference points for fish, and the calculation of the BI is slightly different. Therefore, the detailed calculation steps for phytoplankton and fish are provided in this paper.

[0036] (1) Calculation of Phytoplankton Biointegrity Index (P-IBI)

[0037] ①Determine candidate indicators

[0038] Based on the ecological characteristics, biological population distribution and data availability of the study area, and with reference to relevant research, indicators with clear biological significance and sensitive to changes in environmental factors were selected as candidate indicators.

[0039] ②Determine the reference point

[0040] Reference points represent the most original and natural state of the sea area, and refer to sampling points that are not disturbed by human activities or are minimally disturbed; damaged points refer to sampling points that are disturbed by human activities to varying degrees. Setting reference points can provide a benchmark for measuring the degree of change in biological communities and evaluating the health of water bodies. The ideal reference point should be the data obtained from surveys of undamaged points or minimally damaged sampling points in the same ecological region, or the expected values ​​of each indicator determined based on historical data. Determine reference points based on the data characteristics of different biological groups.

[0041] ③Indicator screening

[0042] The index screening was achieved through discriminant analysis and correlation analysis. The discriminant analysis used box plots to compare the overlap of the IQ (25% to 75% quantile range) of the candidate indexes in the reference point and the damaged point. The boxes had no overlap, and the IQ value was 3; the boxes partially overlapped, but the median was not in the other box, and the IQ value was 2; only one box had a median in the other box, and the IQ value was 1; the medians of both boxes were in the other box, and the IQ value was 0. The index parameters with IQ values ​​greater than or equal to 2 met the conditions, and Pearson correlation analysis was performed to examine the correlation between the indicators. For the two indicators with significant correlation and high information overlap (|r|≥0.9), one of them was selected after comprehensive analysis. Finally, the core indicators for constructing the P-IBI evaluation index system for the nearshore waters of the Yellow River Estuary were obtained.

[0043] ④ IBI calculation and ecological status evaluation of each site

[0044] The IBI value of each station was calculated using the ratio method, and the 95% or 5% quantile value of each core indicator in all sampling stations was taken as the best expected value. Different methods were used to calculate the score of each indicator according to the response of the indicator to interference. For indicators that increase with the increase of interference, the 5% quantile value of the indicator is the best expected value, and the indicator score = (maximum value - measured value) / (maximum value - best expected value); for indicators that decrease with the increase of interference, the 95% quantile value of the indicator is the best expected value, and the indicator score = measured value / best expected value. The total P-IBI score of the station is obtained by adding up the scores of all core indicators at the same station.

[0045] The 25% quantile of the IBI value of the reference point was taken as the ideal expected value (IBIE), and the distribution range smaller than the ideal expected value was divided into four equal parts (Table 1), and the ecological status level of each site was determined according to the total P-IBI score.

[0046] Table 1 Standards for defining ecological status levels

[0047]

[0048] ⑤IBI total score calculation

[0049] The health status of each station was assigned a score of 1, 3, or 5 points. The ecological status of "excellent" was assigned a score of 5 points, the ecological status of "good" and "general" was assigned a score of 3 points, and the ecological status of "poor" and "extremely poor" was assigned a score of 1 point. The equal weight processing method was used to sum up the scores of each station to obtain the phytoplankton integrity index (P-IBI) of the study area. In order to eliminate the difference in IBI values ​​caused by the different number of indicators, formula (1) was used for standardization to obtain the IBI of different months.

[0050]

[0051] Where: P-IBI is the phytoplankton integrity index in the coastal waters of the Yellow River Estuary, C i is the score of the ith station, and n is the number of stations.

[0052] The calculation of biological integrity index for zooplankton and benthic animals is the same as that for phytoplankton.

[0053] (2) Calculation of Fish Biological Integrity Index (F-IBI)

[0054] ①Evaluation index setting

[0055] Based on a full understanding of the characteristics of biological composition and aquatic ecosystems and analysis of a large amount of literature, the selected evaluation indicators are determined. Without going through indicator screening, they are directly used as core indicators to construct an evaluation indicator system.

[0056] ②Determination of reference point

[0057] On the premise that historical data are available in the same study area, the historical data are used as reference points, and the historical results of the corresponding evaluation indicators are used as expected values ​​to analyze the changes relative to past moments.

[0058] ③IBI total score calculation

[0059] Based on the expected value, the measured values ​​of each indicator are divided into three categories, using the 1, 3, and 5 points assignment method. 1 point means that the measured value of the indicator deviates strongly from the expected value, 5 points means that the measured value of the indicator is very close to the expected value, and 3 points is medium. The composite of indicators adopts equal weight processing, and the score of each indicator is added up to get the F-IBI value. The following formula is used for standardization to eliminate the difference in the total F-IBI score caused by the different number of indicators:

[0060]

[0061] Where: F-IBI is the fish biological integrity index, C i is the score of the ith indicator, and n is the number of indicators.

[0062] 2. Calculate the weight of each biological group

[0063] The weight of each biological group is calculated by the average trophic level of each biological group. Phytoplankton is the primary productivity, and the trophic level is set to 1; zooplankton is the secondary productivity, and the trophic level is set to 2; the average trophic level of benthic animals and fish is calculated by combining the trophic level of the species with the resource density.

[0064] The average trophic levels of fish and benthic animals are calculated according to the following formula:

[0065]

[0066] Where: MTL is the average trophic level of the fish / benthic animal community; D i is the relative abundance of the ith fish / benthic animal; TL i is the trophic level of the ith fish / benthic animal.

[0067] The weights are calculated according to the following formula:

[0068]

[0069] Where: W i is the weight of the i-th biological group, MTL i is the average trophic level of the ith biological group.

[0070] 3. Comprehensive evaluation of fishery ecological health

[0071] Based on the weight of each biological group and the total IBI score, the comprehensive value of fishery ecological health was calculated and evaluated according to the health grade evaluation criteria (Table 2).

[0072] CEI=(P-IBI)*W P +(Z-IBI)*W Z +(B-IBI)*W B +(F-IBI)*W F (5)

[0073] Where: CEI is the comprehensive value of fishery ecological health; P-IBI is the phytoplankton integrity index value, W P is the phytoplankton weight; Z-IBI is the zooplankton integrity index value, W Z is the zooplankton weight; B-IBI is the benthic animal integrity index value, W B is the benthic animal weight; F-IBI is the fish integrity index value, W F Weights for fish.

[0074] Table 2 Health level standards

[0075]

[0076] Example 2

[0077] Specific application of the technical solution of embodiment 1

[0078] The multi-class biological integrity ecological health assessment method constructed according to the above method was applied to the Yellow River Estuary waters to carry out the fishery ecological health assessment in the Yellow River Estuary waters. The specific approach is as follows:

[0079] 1. Data Collection

[0080] The data used are from the fishery resources and environment survey conducted in the waters of the Yellow River Estuary in 2020. A total of five voyages were conducted, including: April and May (spring), June and July (summer), and December (winter). Samples of each biological group were collected, preserved, species identified, and biologically determined in accordance with the "Marine Survey Specifications Part 6: Marine Biological Survey" (GB / T12763.6-2007) and the "Marine Fishery Resources Survey Specifications" (SC / T9403-2012). The data used for each biological group are slightly different depending on the data situation and the evaluation object. The fish biological integrity data are bottom trawl data from April, May, June, July, and December; the phytoplankton data are from May, July, and December, the zooplankton data are from May, July, and December, and the benthic animal data are from April, July, and December.

[0081] The survey vessel is a small wooden fishing boat with a length of 12.50m, a width of 4.30m and a depth of 0.95m. 31 survey stations are deployed in the area of ​​119°00′-119°25′E and 37°20′-38°05′N ( Figure 2 ).

[0082] 2. Calculation of single biological group integrity index

[0083] 1. Calculation of phytoplankton biointegrity index

[0084] (1) Selection of candidate indicators

[0085] According to the candidate indicator selection principles, five types including phytoplankton species composition, richness, diversity index, evenness and dominance were selected to construct the indicator system, with a total of 13 candidate indicators (Table 3).

[0086] Table 3 Candidate biological indicators

[0087]

[0088]

[0089] (2) Determination of reference point

[0090] Due to the frequent human activities in the coastal waters of the Yellow River Estuary, there are almost no undisturbed areas. This study refers to relevant literature and the Technical Regulations for Marine Red Tide Monitoring (HYT 069-2005) to determine the reference points and damaged points according to the classification criteria of the biodiversity index H'. H' values ​​of 3 to 4 are clean areas, 2 to 3 are slightly polluted, 1 to 2 are moderately polluted, and <1 is heavily polluted. Sampling points with H'≥3 are set as reference points, and the others are damaged points.

[0091] (3) Index screening

[0092] According to the criteria of the box plot, 6, 8, and 8 indicators in May, July, and December respectively meet the requirements and enter the correlation analysis. For details, see Figure 3-Figure 5 .

[0093] Pearson correlation analysis was performed on the candidate indicators with IQ ≥ 2 (Tables 4 to 6) to ensure that the information expressed by the selected core indicators was independent.

[0094] Table 4 Pearson correlation analysis among the six candidate biological indicators in May

[0095]

[0096] ** indicates significant correlation at the 0.01 level (bilateral), and * indicates significant correlation at the 0.05 level (bilateral). The same applies below.

[0097] Table 5 Pearson correlation analysis among 8 candidate biological indicators in July

[0098]

[0099]

[0100] Table 6 Pearson correlation analysis results among 8 candidate biological indicators in December

[0101]

[0102] All candidate indicators were analyzed by discriminant ability and correlation analysis in turn, and finally the core indicators for calculating the P-IBI in the Yellow River Estuary fishery waters were obtained (Table 7). The number and composition of core indicators in each month were slightly different. In May and December, there were 4 core indicators of P-IBI, and in July, there were 5 core indicators of P-IBI; the Shannon diversity index of phytoplankton (M9) and the richness index of phytoplankton (M11) were core indicators in all three months, and the number of diatom species (M2) was the core indicator of P-IBI in both May and July.

[0103] Table 7 P-IBI core indicators in the Yellow River Estuary fishery waters

[0104]

[0105] (4) IBI calculation and ecological status evaluation of each site

[0106] The core index scores were calculated by the ratio method, and the IBI scores of each station were obtained by accumulating the index scores. The IBI thresholds of the ecological status levels in different months were determined according to the ecological status classification standards, so as to evaluate the ecological status of the coastal waters of the Yellow River Estuary (Table 8)

[0107] Table 8 IBI ecological status classification of sampling points

[0108]

[0109]

[0110] (5) Calculation of IBI total score

[0111] According to the 1, 3, and 5-point assignment method, the IBI evaluation results of each station were scored, and the scores were cumulatively added and standardized (Formula 1) to obtain the phytoplankton integrity index (P-IBI) of the coastal waters of the Yellow River Estuary. After calculation, the P-IBI in May, July, and December were 34.45, 44.52, and 44.52, respectively, and the annual P-IBI average of the three months was 41.16.

[0112] 2. Calculation of Zooplankton Biointegrity Index

[0113] The calculation steps of the zooplankton biointegrity index are the same as those of the phytoplankton biointegrity index. For details, please refer to "Example 2 (II) 1. Calculation of phytoplankton biointegrity index". The zooplankton uses the water quality of Grade II or above and the season with the minimum runoff as the reference area and impact period. The candidate indicators, core evaluation indicators and ecological status level division thresholds of zooplankton are shown in Tables 9 to 11 respectively.

[0114] Table 9 Candidate indicators for Z-IBI in the Yellow River Estuary fishery waters

[0115]

[0116]

[0117] Table 10 Z-IBI core indicators for the Yellow River Estuary fishery waters

[0118]

[0119] Table 11 Thresholds for ecological status classification

[0120]

[0121] According to the 1, 3, and 5-point assignment method, the IBI evaluation results of each station were scored, and the scores were cumulatively added and standardized to obtain the zooplankton integrity index (Z-IBI) of the coastal waters of the Yellow River Estuary. May: 49.9 points, July: 20.5 points, December: 53.8 points, and the annual Z-IBI value was the average of the three months, which was 41.40.

[0122] 3. Calculation of benthic animal biointegrity index

[0123] The calculation steps of benthic animal biointegrity index are the same as those of phytoplankton biointegrity index. For details, please refer to "Example 2 (II) 1. Calculation of phytoplankton biointegrity index". Benthic animals use stations with low pollution, high dissolved oxygen and relatively long distance from the shore as reference points. Benthic animal candidate indicators, core evaluation indicators and ecological status level classification thresholds are shown in Tables 12-14.

[0124] Table 12 Candidate indicators for B-IBI in the Yellow River Estuary fishery waters

[0125]

[0126] Table 13 B-IBI core indicators in the Yellow River Estuary fishery waters

[0127]

[0128] Table 14 B-IBI ecological status classification and assessment results of sampling points

[0129]

[0130]

[0131] According to the 1, 3, and 5-point assignment method, the IBI evaluation results of each station were scored, and the scores were cumulatively added up and standardized to obtain the benthic animal integrity index (B-IBI) of the coastal waters of the Yellow River Estuary. April: 36 points, July: 33.43 points, December: 58.45 points; the annual B-IBI average of the three months was 42.63.

[0132] 4. Calculation of fish biological integrity index

[0133] (1) Evaluation index setting

[0134] With reference to relevant studies, based on the characteristics of fish composition in the Yellow River estuary and nearshore waters, the characteristics of aquatic ecosystems and data availability, 14 indicators in three categories were set up to construct the F-IBI evaluation index system, including species composition and abundance, reproductive symbionts and nutritional structure (Table 15).

[0135] Table 15 Evaluation index system of fish biological integrity index (F-IBI) in the coastal waters of the Yellow River Estuary

[0136]

[0137] (2) Determination of reference point

[0138] The historical data of the study area were used as reference points, the historical survey data from 2013 to 2014 and some literature data were used as reference points, and the historical values ​​of the corresponding indicators were used as expected values.

[0139] (3) Calculation of IBI total score

[0140] Taking the historical data from 2013 to 2014 as a reference point, the indicator results were obtained based on the survey data, and the 1, 3, 5 assignment method was used to obtain the assignment standards for each indicator of the fish biological integrity index in the nearshore fishery waters of the Yellow River Estuary. After standardization, the fish biological integrity index (F-IBI) was calculated to be 48 points.

[0141] Table 16 IBI index scoring standards and evaluation results for fish in the Yellow River Estuary and coastal waters

[0142]

[0143] (III) Calculation of weights of each biological group

[0144] According to Zhang Bo's (2018) study on the trophic level of fish in the Bohai Sea, the trophic levels of various fish were referred to, and the average trophic level was used for the species that were not available. The specific regulations were as follows: the average trophic level of low-trophic fish was 3.36, the average trophic level of medium-trophic fish was 4.25, and the average trophic level of high-trophic fish was 4.51. Among them, low-trophic fish include: ① omnivorous fish, ② fish that mainly feed on zooplankton, ③ fish that mainly feed on benthic animals, and ④ fish that mainly feed on zooplankton and benthic animals; medium-trophic fish include: ① mainly feed on benthic animals and fish food, ② mainly feed on zooplankton, benthic animals and fish food; high-nutrient fish mainly feed on fish food. Combined with the density of various types of fish resources, the average trophic level of fish was calculated to be 3.55 (Formula 3).

[0145] Table 17 Fish resource density and trophic level

[0146]

[0147]

[0148] According to the revised values ​​of the trophic levels of various categories of benthic organisms by Zhang Bo et al. (2004), combined with the resource density of each category, the average trophic level of benthic animals was calculated to be 2.46 (Formula 3).

[0149] Table 18 Resource density and trophic level of each category of benthic animals

[0150]

[0151] According to the weight calculation formula (Formula 4), the weight of phytoplankton is 0.1109, the weight of zooplankton is 0.2220, the weight of benthic animals is 0.2730, and the weight of fish is 0.3941.

[0152] 4. Comprehensive evaluation of fishery ecological health

[0153] According to the comprehensive evaluation formula, the comprehensive index value of ecological health of the Yellow River Estuary waters is calculated.

[0154] CEI=(P-IBI)*W P +(Z-IBI)*W Z +(B-IBI)*W B +(F-IBI)*WF

[0155] =P-IBI*0.1109+Z-IBI*0.2220+B-IBI*0.2730+F-IBI*0.3941

[0156] =41.16*0.1109+41.40*0.2220+42.63*0.2730+48*0.3941

[0157] =44.3102

[0158] According to the health assessment grade standards (Table 2), compared with 2013-2014, the health status of the ecosystem in the coastal waters of the Yellow River Estuary is between "poor" and "fair", and is more inclined to "poor".

[0159] The ecological health status of fisheries in the Yellow River Estuary in 2020 was between "general" and "healthy", tending towards "general". Wang Guangzhou et al. (2023) used the "Driving Force-Pressure-State-Impact-Response (DPSIR)" model to construct an evaluation index system of 28 factors including population growth rate, annual runoff, eutrophication index, phytoplankton diversity index and ecological environment governance investment, and evaluated that the ecosystem of the Yellow River Estuary and adjacent waters in 2020 was in a "healthy" state, which is basically consistent with the evaluation results of this study.

Claims

1. A method for assessing the ecological health of estuarine fisheries, characterized in that: The method divides the research object of estuarine fishery ecological health assessment into biological groups according to the trophic level of the whole food chain. The divided single biological groups are phytoplankton, zooplankton, benthic animals and fish. Then, data is obtained through the collection, preservation, species identification and biological determination of samples in the estuary to be assessed, which is used to construct the biological integrity index of the single biological group, and then the weight of each single biological group is calculated for comprehensive evaluation. The method for calculating the weight of each single biological group is to calculate the average trophic level of each biological group: Step 1: Phytoplankton is taken as primary productivity, and the average trophic level is set to 1; zooplankton is taken as secondary productivity, and the average trophic level is set to 2; the average trophic level of benthic animals and fish is calculated by combining the trophic level of species with the resource density, all calculated according to the following formula: Where: MTL is the average trophic level of the fish / benthic animal community; D i is the relative abundance of the ith fish / benthic animal; TL i is the trophic level of the ith fish / benthic animal; The second step is to calculate the weight according to the following formula: Where: W i is the weight of the i-th biological group, MTL i is the average trophic level of the ith biological group; The method for constructing the biotic integrity index of a single biological group is as follows: ①Determine candidate indicators ②Determine reference points ③Screen indicators through discriminant ability analysis and correlation analysis ④Calculate IBI and evaluate ecological status of each site ⑤Calculate the total IBI score.

2. The method for assessing the ecological health of estuarine fisheries according to claim 1, characterized in that: The comprehensive evaluation of fishery ecological health is to calculate the comprehensive value of fishery ecological health based on the weight of each single biological group and the total score of IBI, and evaluate it according to the health grade evaluation standard, see Table 2; CEI=(P-IBI)*W P +(Z-IBI)*W Z +(B-IBI)*W B +(F-IBI)*W F (5) Where: CEI is the comprehensive value of fishery ecological health; P-IBI is the phytoplankton integrity index value, W P is the phytoplankton weight; Z-IBI is the zooplankton integrity index value, W Z is the zooplankton weight; B-IBI is the benthic animal integrity index value, W B is the benthic animal weight; F-IBI is the fish integrity index value, W F Weighting of fish; Table 2 Health level standards 3. The method for assessing the ecological health of estuarine fisheries according to claim 2, characterized in that: The method for constructing the biotic integrity index of a single biological group is as follows: ①Determine candidate indicators ②Determine reference points ③Screen indicators through discriminant ability analysis and correlation analysis ④Calculate IBI and evaluate ecological status of each site ⑤Calculate the total IBI score.

4. An application of the estuarine fishery ecological health assessment method according to any one of claims 1 to 3 to manage estuarine ecology.

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