A method for habitat delineation and assessment based on fish life history

Abstract

This invention discloses a method for habitat delineation and assessment based on fish life history, belonging to the field of fish management technology. The method includes the following steps: Step 1, identifying the target fish species; Step 2, determining the life history of the target fish species: clarifying the ecological habits of the target fish species, as well as their spawning grounds, feeding grounds, overwintering grounds, and migration routes; Step 3, determining the protected habitat area for the target fish species: defining the river sections involved in the spawning grounds, feeding grounds, overwintering grounds, and migration routes of a specific target fish species as its protected habitat area; Step 4, quantitatively evaluating the importance of the river sections and clarifying the content of habitat protection. Delineating fish habitats based on fish life history focuses on the fish's life history and improves habitat protection content from the perspective of protecting the life history of the target fish species. Specifically, it refines the protection content according to different times and ranges, meeting the spatial and temporal needs of fish for reproduction in their habitats.

Description

Technical Field

[0001] This invention relates to a method for habitat classification and assessment based on the life history of fish, belonging to the field of fish management technology. Background Technology

[0002] Fish habitats refer to the places where fish can maintain their normal life, growth, foraging, reproduction, and other life cycles. This includes the aquatic areas necessary for fish to complete their entire life cycle, such as spawning grounds, feeding grounds, overwintering grounds, and migratory channels connecting different life stages. The construction of river dams and the development of aquatic production and business activities can alter the environmental conditions of riverine fish habitats, thus profoundly impacting fish resources and biodiversity. Therefore, the rational delineation of fish habitats is of great significance for their protection and ensuring the normal life, growth, foraging, and reproduction of fish. Currently, some methods for delineating fish habitats exist, such as:

[0003] Chinese patent document CN106012947A discloses a method for classifying fish habitats based on topographical conditions. Based on topographical features such as longitudinal morphology of river channels, transverse morphology of river channels, and local morphology of river channels, the method classifies the protected area of ​​fish habitats, grades the degree of protection, and classifies the protected content.

[0004] Chinese patent document CN112766594A discloses a method for calculating the suitable area of ​​river fish habitat based on ecological habits. Based on research to establish the response relationship between target fish and environmental factors, water depth, flow velocity, and bottom sediment are selected as indicators for calculating the suitable area of ​​fish habitat. The suitability of the habitat is judged based on the calculated suitable area of ​​fish habitat.

[0005] Chinese patent document with publication number CN106035163A discloses a method for classifying fish habitats based on hydrodynamic conditions. Based on two types of hydrodynamic characteristic factors, namely water flow movement index and water flow energy index, the method classifies the protection scope, protection level, and protection content of fish habitats.

[0006] However, none of the above-mentioned methods for delineating fish habitats have fully considered the needs of fish life, nor have they proposed methods for delineating and assessing habitats based on fish life history. Summary of the Invention

[0007] To address the aforementioned technical problems, this invention provides a method for habitat classification and assessment based on fish life history.

[0008] This invention is achieved through the following technical solution:

[0009] A method for habitat delineation and assessment based on fish life history includes the following steps:

[0010] Step 1: Identify the target fish species: Determine the species of the target fish and assign them numbers according to their species;

[0011] Step 2: Determine the life history of the target fish: Clarify the ecological habits of the target fish, as well as its spawning grounds, feeding grounds, overwintering grounds, and migration routes. Then, in conjunction with the target fish's identification number, represent its spawning grounds, feeding grounds, overwintering grounds, and migration routes with the symbols C, S, Y, and H.

[0012] Step 3: Determine the protected habitat range of the target fish species: The river sections involved in the spawning grounds, feeding grounds, overwintering grounds and migration channels of a certain target fish species are designated as its protected habitat range. Similarly, the protected habitat range of the remaining target fish species is determined, and the habitat range is delineated based on the fish life history.

[0013] Step 4: Quantitatively assess the importance of river sections and clarify the content of habitat protection: Draw a map of fish habitats, quantitatively assess the importance of each river section based on the functional needs of different river sections involved in the life history of the target fish, and determine the content of protection for each habitat.

[0014] In step one, after identifying the species of the target fish, the target fish are first classified into different levels according to their species, then ranked according to their importance, and finally numbered according to their ranking. The numbers are represented as 1, 2, 3...n, where n is a natural number.

[0015] In step one, the target fish species are classified into five levels: national and provincial protection level, critically endangered, vulnerable, near endangered, and least endangered.

[0016] The ecological habits of the target fish in step two include their living habits, feeding habits, reproductive habits, and migration habits.

[0017] The method for drawing fish habitat delineation maps in step four includes the following steps:

[0018] Step 1: Draw a simplified map of the river, which includes the main stream and tributaries;

[0019] Step 2: Use graphic symbols of different shapes to mark the spawning grounds, feeding grounds and overwintering grounds of the target fish in the corresponding positions on the simplified river map, and mark their representative symbols near the graphic symbols of the spawning grounds, feeding grounds and overwintering grounds of the target fish.

[0020] Step 3: Use dashed lines to represent the migration channels of the target fish, and connect the graphic symbols of the spawning grounds, feeding grounds and overwintering grounds of the target fish with dashed lines to obtain the CSY connecting line. The river section involved in the CSY connecting line is the habitat protection area of ​​the target fish.

[0021] Step 4: Repeat steps 2 and 3 to complete the drawing of CSY connecting lines for all target fish species, thus obtaining the fish habitat division map.

[0022] The higher the density of the CSY connecting line in a certain river section of the fish habitat classification map, the greater the importance of that river section.

[0023] The habitat protection measures in step four include the protection time for spawning grounds, feeding grounds, overwintering grounds, and migration routes.

[0024] The protection period for spawning grounds coincides with the spawning time of the target fish species; the protection period for feeding grounds is 1 to 5 months after the end of the spawning season; and the protection period for overwintering grounds is between November and February.

[0025] During the protection period of the spawning grounds, all water-related production, business, and construction activities are prohibited within the spawning grounds; during the protection period of the feeding grounds, activities that reduce the amount of food available to the target fish in the feeding grounds are prohibited or reduced; during the protection period of the overwintering grounds, activities that affect the water temperature in the overwintering grounds are prohibited or reduced.

[0026] The protection of migration channels refers to the fact that the construction of river-blocking facilities should not obstruct the migration channels of target fish species.

[0027] The beneficial effects of this invention are as follows:

[0028] 1. Habitat delineation and assessment methods based on fish life history can quickly determine the scope of habitat protection, key protection periods, and key protection contents. Taking into account the fish life history, the delineated fish habitats can be as close as possible to the fish's living and breeding conditions.

[0029] 2. Fish habitat delineation is carried out based on fish life history. Attention is paid to fish life history, and the content of habitat protection is improved from the perspective of life history. That is, the specific protection content is improved according to different time and different range, so as to meet the space and time required for fish to reproduce in the habitat.

[0030] 3. First, classify the target fish species into different levels, then sort and number them according to their importance. The smaller the number, the higher the level and the more important the target fish species. Combined with relevant letters, these form representative symbols C, S, Y, and H for the spawning grounds, feeding grounds, overwintering grounds, and migration channels of the corresponding target fish species. This facilitates the rapid location of the habitat range of various target fish species on the fish habitat classification map, and allows for quick understanding of the habitat location and importance of the target fish species, as well as the specific location of the spawning grounds, feeding grounds, overwintering grounds, and migration channels of various target fish species. This facilitates the implementation of targeted protection measures for the target fish habitats and their spawning grounds, feeding grounds, overwintering grounds, and migration channels in the future.

[0031] 4. Based on the spawning grounds, feeding grounds, overwintering grounds, and migration channels in the fish habitat, specific protection measures are formulated, which greatly improves the effectiveness of fish habitat protection. At the same time, the protected area is minimized, and the impact of habitat protection on water activities in other river sections is reduced as much as possible. It can effectively reduce the impact of reservoir dam construction on target fish species, and has good economic and social benefits, making it suitable for widespread use. Attached Figure Description

[0032] Figure 1 This is a simplified diagram of the fish life cycle according to the present invention;

[0033] Figure 2 This is a map showing the fish habitat classification according to the present invention. Detailed Implementation

[0034] The technical solution of the present invention is further described below, but the scope of protection is not limited to what is described.

[0035] like Figure 1 and Figure 2 As shown, the habitat delineation and assessment method based on fish life history described in this invention includes the following steps:

[0036] Step 1: Identify the target fish species: Clearly define the species of the target fish and assign them numbers accordingly. This is primarily done based on national and provincial lists of key protected wild animals, the *China Red Data Book of Endangered Animals - Fish*, the *China Red List of Species*, and the *China Red List of Biodiversity*. Numbering the target fish by species facilitates differentiation between different species and makes it easier to create easily identifiable fish habitat maps later.

[0037] Step Two: Determine the Life History of the Target Fish Species: Clarify the ecological habits of the target fish species, as well as their important spawning grounds, feeding grounds, overwintering grounds, and migration channels. Then, based on the target fish species' identification numbers, assign representative symbols (C, S, Y, and H) to their important spawning grounds, feeding grounds, overwintering grounds, and migration channels. Based on relevant fish data, investigate the locations required by the target fish species, mainly categorized as spawning grounds, feeding grounds, overwintering grounds, and migration channels. Spawning grounds are specific locations for fish to reproduce, requiring extremely high ecological and hydrological conditions; the effective area of ​​a spawning ground significantly impacts population size. Feeding grounds are where fish feed from a young age, and their importance is relatively less pronounced. Overwintering grounds are locations chosen by fish to inhabit when water temperatures drop in winter; these locations must simultaneously meet three necessary conditions: water temperature, water depth, and food availability. Migration channels are the waterways connecting spawning grounds, feeding grounds, and overwintering grounds.

[0038] Step 3: Determine the protected habitat range for the target fish species. The river sections involved in the important spawning grounds, feeding grounds, overwintering grounds, and migration routes of a particular target fish species are designated as its protected habitat range. Similarly, the protected habitat ranges for the remaining target fish species are determined, completing the habitat delineation based on fish life history. This method, which uses the river sections involved in the spawning grounds, feeding grounds, overwintering grounds, and migration routes of the target fish species as its protected habitat range, and based on the natural life history of the target fish, establishes a habitat delineation method. This method is simple and, while satisfying the life history of the target fish, maximizes the satisfaction of their habitat and reproduction needs, promoting the maintenance of the target fish population and species diversity.

[0039] Step 4: Quantitatively assess the importance of river sections and clarify the content of habitat protection: Draw a map of fish habitats, quantitatively assess the importance of each river section based on the functional needs of different river sections involved in the life history of the target fish, and determine the content of protection for each habitat.

[0040] In step one, after identifying the target fish species, the target fish are first classified into different levels according to their species, then ranked according to their importance, and finally numbered according to their ranking. The numbers are sequentially represented as 1, 2, 3…n, where n is a natural number. First, the target fish are classified into different levels, then ranked and numbered according to their importance. The smaller the number, the higher the level and the more important the target fish. Combined with relevant letters, these form representative symbols C, S, Y, and H for the spawning grounds, feeding grounds, overwintering grounds, and migration routes of the corresponding target fish species. This facilitates the rapid location of the habitat ranges of various target fish species on the fish habitat classification map, quickly ascertaining the location and importance of the target fish habitats, and identifying the specific locations of the spawning grounds, feeding grounds, overwintering grounds, and migration routes of various target fish species. This allows for targeted protection measures to be taken for the target fish habitats and their spawning grounds, feeding grounds, overwintering grounds, and migration routes in the future.

[0041] In step one, the target fish species are classified into five levels: national and provincial protection level, critically endangered, vulnerable, near endangered, and least endangered.

[0042] The ecological habits of the target fish in step two include their living habits, feeding habits, reproductive habits, and migration habits.

[0043] The method for drawing fish habitat delineation maps in step four includes the following steps:

[0044] Step 1: Draw a simplified map of the river, which includes the main stream and tributaries;

[0045] Step 2: Use graphic symbols of different shapes to mark the important spawning grounds, feeding grounds and overwintering grounds of the target fish in the corresponding positions on the simplified river map, and mark their representative symbols near the graphic symbols of the target fish's spawning grounds, feeding grounds and overwintering grounds.

[0046] Step 3: Use dashed lines to represent the migration channels of the target fish, and connect the graphic symbols of the important spawning grounds, feeding grounds and overwintering grounds of the target fish with dashed lines to obtain the CSY connecting line. The river section involved in the CSY connecting line is the habitat protection area of ​​the target fish.

[0047] Step 4: Repeat steps 2 and 3 to complete the drawing of CSY connecting lines for all target fish species, thus obtaining the fish habitat classification map. Different target fish species have different CSY connecting lines. The higher the density of CSY connecting lines in a certain river segment, the greater the importance of that segment. Based on the CSY connecting lines and migration channels H, a quantitative analysis of each river segment is conducted to determine the protection scope, importance assessment, and protection content analysis for each habitat.

[0048] The higher the density of the CSY connecting line in a certain river section of the fish habitat classification map, the greater the importance of that river section.

[0049] The habitat protection measures in step four include the protection time for spawning grounds, feeding grounds, overwintering grounds, and migration routes.

[0050] The protection period for spawning grounds coincides with the spawning time of the target fish species; the protection period for feeding grounds is 1 to 5 months after the end of the spawning season; and the protection period for overwintering grounds is between November and February.

[0051] During the protection period of the spawning grounds, all water-related production, business, and construction activities are prohibited within the spawning grounds; during the protection period of the feeding grounds, activities that reduce the food supply for target fish in the feeding grounds are prohibited or reduced; during the protection period of the overwintering grounds, activities that affect the water temperature in the overwintering ground area are prohibited or reduced. Specific protection measures were formulated based on the spawning grounds, feeding grounds, overwintering grounds, and migration channels within the fish habitat, significantly improving the effectiveness of fish habitat protection while minimizing the protected area and reducing the impact of habitat protection on water-related activities in other river sections.

[0052] The protection of migration channels refers to the principle that the construction of river-blocking facilities should not obstruct the migration channels of target fish species. This can effectively reduce the impact of the construction of reservoirs, dams, and other similar structures on target fish species.

[0053] Example 1:

[0054] The process of determining the habitat classification for a certain watershed is as follows:

[0055] (1) Target fish identification

[0056] Based on the survey of natural targets in the river, the main target fish species for protection are *Schizothorax glabra*, *Gymnocypris nagi*, and *Schizothorax gracilis*. There are no nationally or provincially protected fish species. One target fish species, *Gymnocypris nagi*, is listed in the *China Red Data Book of Endangered Animals - Fish*, classified as Vulnerable; two target fish species are listed in the *China Species Red List*, *Gymnocypris nagi* and *Schizothorax gracilis*, with *Gymnocypris nagi* classified as Vulnerable and *Schizothorax gracilis* as Critically Endangered; three target fish species are listed in the *China Red List of Biodiversity*, *Gymnocypris nagi*, *Schizothorax gracilis*, and *Schizothorax glabra*, with *Gymnocypris nagi* classified as Vulnerable, *Schizothorax gracilis* as Critically Endangered, and *Schizothorax glabra* as Least Concern. The target fish species are ranked according to importance as follows: *Schizothorax gracilis*, *Gymnocypris nagi*, and *Schizothorax glabra*, corresponding to the numbers 1, 2, and 3.

[0057] (2) Determination of fish life history

[0058] According to relevant research data, the fine-tailed catfish (1) typically inhabits rocky areas along fast-flowing banks, primarily feeding on annelids. It is benthic and its spawning season is estimated to be from July to September. It overwinters in deeper waters and exhibits short-distance migratory behavior. The smaller *Gymnocypris chinensis* (2) usually inhabits areas with slower currents along the banks, mainly feeding on aquatic insects and chironomid larvae, and also consuming various diatoms. Its breeding season is from April to May, producing adhesive eggs. It overwinters in deeper waters. The *Schizothorax glabripennis* (3) mostly lives in main streams, is benthic, and feeds primarily on algae. It uses its sharp lower jaw to scrape algae attached to rocks. Its breeding season is from March to May, spawning in the upper reaches of tributaries, producing adhesive eggs. It overwinters in deeper waters.

[0059] (3) Determining the connection between points

[0060] The investigation revealed that the spawning ground of *Siniberis scutellarioides* 1 is C1, its feeding ground is S1, its overwintering ground is Y1, and its migration channel is H1. The spawning ground of *Gymnocypris chinensis* 2 is C2, its feeding ground is S2, its overwintering ground is Y2, and its migration channel is H2. The spawning ground of *Schizothorax glabripennis* 3 is C3, its feeding ground is S3, its overwintering ground is Y3, and its migration channel is H3.

[0061] (4) Habitat delineation and determination

[0062] Based on the basic life cycle of each target fish species—spawning, feeding, and overwintering—the spawning grounds, feeding grounds, and overwintering grounds are connected, with the connecting lines representing migration routes. See details below. Figure 2 Based on the connecting lines, the river sections involved in the connection of S1-C1-Y1-S1, S2-C2-Y2, and C3-S3-Y3-C3-S3 are designated as fish habitat protection areas.

[0063] (5) Habitat protection time and protection content, etc.

[0064] Based on the basic life history of each target fish species, the protection period for the spawning ground C1 of the slender-tailed catfish is determined to be from July to September, during which all water-related production, business, and construction activities are prohibited; the protection period for the feeding ground S1 is from October to November, during which activities affecting planktonic plants and benthic animals are mainly controlled; the protection period for the overwintering ground Y1 is from December to February, during which activities affecting the regional water temperature are mainly controlled; S1-C1-Y1-S1 is a migration channel, and the construction of river-blocking facilities in the area is mainly controlled.

[0065] The protection period for the spawning ground C2 of the naked-bellied leaf-barked fish 2 is determined to be from April to May, during which all water-related production, business, and construction activities are prohibited; the protection period for the feeding ground S2 is from June to October, during which activities affecting planktonic plants and benthic animals are mainly controlled; the protection period for the overwintering ground Y2 is from November to February, during which activities affecting water temperature in the area are mainly controlled; S2-C2-Y2 is a migratory channel, and the construction of river dams is mainly controlled in this section.

[0066] The protection period for the spawning ground C3 of the schizothorax 'Schwarzkopf' is determined to be from March to May, during which all water-related production, business, and construction activities are prohibited; the protection period for the feeding ground S3 is from June to October, during which activities affecting planktonic plants and benthic animals are mainly controlled; the protection period for the overwintering ground Y3 is from November to February, during which activities affecting water temperature in the area are mainly controlled; C3-S3-Y3-C3-S3 is the migration channel, and the construction of river dams is mainly controlled in this section.

Claims

1. A method for habitat delineation and assessment based on fish life history, characterized in that: Includes the following steps: Step 1: Identify the target fish species: Determine the species of the target fish and assign them numbers according to their species; Step 2: Determine the life history of the target fish: Clarify the ecological habits of the target fish, as well as its spawning grounds, feeding grounds, overwintering grounds, and migration routes. Then, in conjunction with the target fish's identification number, represent its spawning grounds, feeding grounds, overwintering grounds, and migration routes with the symbols C, S, Y, and H. Step 3: Determine the protected habitat range of the target fish species: The river sections involved in the spawning grounds, feeding grounds, overwintering grounds and migration channels of a certain target fish species are designated as its protected habitat range. Similarly, the protected habitat range of the remaining target fish species is determined, and the habitat range is delineated based on the fish life history. Step 4: Quantitatively assess the importance of river sections and clarify the content of habitat protection: Draw a map of fish habitats, quantitatively assess the importance of each river section based on the functional needs of different river sections involved in the life history of the target fish, and determine the content of protection for each habitat. In step one, after identifying the species of the target fish, the target fish are first classified into different levels according to their species, then ranked according to their importance, and finally numbered according to their ranking. The numbers are represented as 1, 2, 3...n, where n is a natural number. In step one, the target fish species are classified into five levels: national and provincial protection level, critically endangered, vulnerable, near endangered, and least endangered. The ecological habits of the target fish in step two include their living habits, feeding habits, reproductive habits, and migration habits; The method for drawing fish habitat delineation maps in step four includes the following steps: Step 1: Draw a simplified map of the river, which includes the main stream and tributaries; Step 2: Use graphic symbols of different shapes to mark the spawning grounds, feeding grounds and overwintering grounds of the target fish in the corresponding positions on the simplified river map, and mark their representative symbols near the graphic symbols of the spawning grounds, feeding grounds and overwintering grounds of the target fish. Step 3: Use dashed lines to represent the migration channels of the target fish, and connect the graphic symbols of the spawning grounds, feeding grounds and overwintering grounds of the target fish with dashed lines to obtain the CSY connecting line. The river section involved in the CSY connecting line is the habitat protection area of ​​the target fish. Step 4: Repeat steps 2 and 3 to complete the drawing of CSY connecting lines for all target fish species, thus obtaining the fish habitat division map.

2. The habitat delineation and assessment method based on fish life history as described in claim 1, characterized in that: The higher the density of the CSY connecting line in a certain river section of the fish habitat classification map, the greater the importance of that river section.

3. The habitat delineation and assessment method based on fish life history as described in claim 1, characterized in that: The habitat protection measures in step four include the protection time for spawning grounds, feeding grounds, overwintering grounds, and migration routes.

4. The habitat delineation and assessment method based on fish life history as described in claim 3, characterized in that: The protection period for spawning grounds coincides with the spawning time of the target fish species; the protection period for feeding grounds is 1 to 5 months after the end of the spawning season; and the protection period for overwintering grounds is between November and February.

5. The habitat delineation and assessment method based on fish life history as described in claim 3 or 4, characterized in that: During the protection period of the spawning grounds, all water-related production, business operations, and construction activities are prohibited within the spawning grounds; during the protection period of the feeding grounds, activities that reduce the amount of food available to the target fish in the feeding grounds are prohibited or reduced. During the protection period of the overwintering site, activities that affect the water temperature of the overwintering site area shall be prohibited or reduced.

6. The habitat delineation and assessment method based on fish life history as described in claim 3, characterized in that: The protection of migration channels refers to the fact that the construction of river-blocking facilities should not obstruct the migration channels of target fish species.

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