An egg laying site suitability calculation method considering hatching ability

Abstract

This invention discloses a method for calculating spawning ground suitability that takes into account hatching capacity. Based on the habitat factor suitability curve for fish spawning periods, the method calculates the spawning ground suitability during the spawning period. Then, considering the time required for egg drift and hatching, it calculates the drift and hatching period suitability. The combined method yields a comprehensive spawning ground suitability that balances hatching capacity. This method comprehensively considers both habitat factors during the spawning period and the time required for drift and hatching, resulting in a spawning ground suitability that better meets the needs of fish spawning and hatching. It considers not only the requirements for water depth, flow velocity, and water temperature during the spawning period but also the requirements for water flow velocity and drift distance for egg drift and hatching after spawning. This method is of great significance for more scientifically guiding the selection of spawning ground restoration locations.

Description

Technical Field

[0001] This invention relates to the field of ecological hydraulics technology, specifically to a method for calculating the suitability of spawning grounds while taking into account hatching capacity. Background Technology

[0002] Drifting-egg fish, as fish species with relatively complete monitoring data in the upper reaches of the Yangtze River, are frequently used as indicator species. By analyzing the spawning time and spawning grounds of drifting-egg fish, regional ecological flows can be obtained. Ecological flows are a crucial foundation for protecting the survival and reproduction of fish species. Therefore, studying the spawning grounds and habitats of drifting-egg fish is of great significance for maintaining regional fish habitats, protecting fish species, and conserving biodiversity.

[0003] The key life cycles of fish mainly include the spawning and reproductive period (spawning and hatching), migration, and overwintering. In existing studies of spawning grounds for drifting fish, spawning ground suitability is based on habitat characteristics during the spawning period. However, many drifting fish eggs face insufficient time and distance for hatching, resulting in extremely low survival rates during the spawning and hatching period, directly impacting fish population structure. Therefore, this paper proposes a spawning ground suitability calculation method that considers hatching capacity. This method can be used to determine areas within rivers suitable for fish spawning and where the eggs can effectively hatch, providing technical support for locating fish spawning grounds and rationally determining spawning ground restoration sites.

[0004] In summary, this invention provides a method for calculating the suitability of spawning grounds while taking into account hatching capacity, aiming to solve the above-mentioned problems. Summary of the Invention

[0005] The purpose of this invention is to provide a spawning ground suitability calculation method that takes into account hatching capacity, which can obtain a spawning ground suitability that better meets the needs of fish during the spawning and hatching period, thereby improving the survival rate of fish during the spawning and hatching period. This is of great significance for maintaining regional fish habitats, protecting the survival of fish species, and protecting biodiversity.

[0006] To achieve the above-mentioned objectives, this invention discloses a method for calculating spawning ground suitability that takes into account hatching capacity. It comprehensively considers habitat factors during the fish spawning period and the time conditions required for the drift hatching period. Based on the suitable water depth, flow velocity, and water temperature curves for the fish spawning period, the spawning ground suitability is calculated. Furthermore, considering the water flow velocity and drift distance required for fish egg drift hatching while meeting the spawning period suitability, the drift hatching period suitability is calculated. The comprehensive suitability of the spawning ground, taking into account both factors, is obtained. The method includes the following steps:

[0007] S1: Select a species of drifting-egg-laying fish from the target area, collect topographic and hydrological data of the drifting-egg-laying fish during the spawning and drifting-hatching periods in the target area, establish a hydrodynamic model for the target area, and use the hydrodynamic model to simulate the changes in hydrodynamic indicators of the region's characteristic hydrological year to obtain the habitat factor suitability curve for the spawning period of the drifting-egg-laying fish. The habitat factors include water depth, flow velocity, and water temperature.

[0008] S2: Based on the suitability curves of habitat factors during the spawning period of the drifting-egg-laying fish, a preliminary habitat model is established; the target area is divided into grids, and each grid is used as a unit. The suitability of the unit's habitat factors is calculated according to the preliminary habitat model as the suitability of the spawning ground during the spawning period, as follows: , , ;

[0009] S3: Calculate the suitability of fish drifting incubators;

[0010] S4: Multiply the spawning site suitability during the spawning season by the fish drifting incubator suitability to calculate the overall spawning site suitability.

[0011] Furthermore, step S1 specifically includes:

[0012] (1.1) Select fish species that lay drifting eggs in the target area, monitor and organize data such as the spawning time, spawning site location, spawning site habitat characteristics, and time required for drifting and hatching, and collect topographic and hydrological data of the fish species that lay drifting eggs in the target area during the spawning period and drifting and hatching period;

[0013] (1.2) Establish a hydrodynamic model for the target area, and use the hydrodynamic model to simulate the changes in hydrodynamic indicators during the characteristic hydrological year of the region, so as to obtain the suitable curve of habitat factors during the spawning period of drifting spawning fish.

[0014] Furthermore, step (1.2) specifically includes the following steps:

[0015] (1.2.1) Collect underwater topographic and hydrological data of the target area, and analyze the characteristic annual hydrological conditions;

[0016] (1.2.2) The target area is divided into grids to achieve full coverage of the area. Hydrodynamic and water temperature models are used, with the characteristic flow processes of abundant, normal and dry seasons as the inflow boundaries, to calculate the changes in regional flow velocity, water depth and water temperature.

[0017] (1.2.3) Based on the grid and characteristic hydrological year conditions, establish a hydrodynamic model for the target area, simulate the change process of hydrodynamic indicators in the characteristic hydrological year of the area, and obtain the habitat factor suitability curves for drifting oviparous spawning periods, including flow velocity, water depth, and water temperature suitability curves.

[0018] Furthermore, step S3 specifically includes:

[0019] (3.1) Calculate the distance between the spawning ground and the nearest water-retaining structure based on the location of the spawning ground and the river flow velocity;

[0020] (3.2) Calculate the time T for fish eggs to drift based on the distance between the spawning ground and the nearest water-retaining structure and the water flow velocity. i ;

[0021] (3.3) The time T for the fish eggs to drift i The time required for the hatching of drifting fish eggs Compare, if T i > This indicates that the fish egg drifting time meets the hatching requirements, and the suitability of the fish drifting incubator is 1; otherwise, the suitability of the fish drifting incubator is 0.

[0022]

[0023] In the formula: Suitability of fish drift incubator; This refers to the distance between the unit and the downstream water-retaining structure. The flow velocity at the unit; The time required for the hatching of drifting fish eggs.

[0024] Furthermore, step S4 specifically includes:

[0025] The overall suitability of fish spawning grounds is calculated using the following formula:

[0026]

[0027] In the formula: To ensure the suitability of the spawning grounds for unit i while also considering hatching capacity, the spawning grounds are comprehensively...

[0028] Suitability reflects whether the habitat of fish in a river is suitable for spawning, and also indicates whether the fish eggs in the area can safely hatch and survive.

[0029] The present invention has the following beneficial effects:

[0030] This invention, in calculating the suitability of spawning grounds for drifting fish, comprehensively considers habitat factors during the spawning period and the time conditions required for drifting and hatching. It obtains the suitability of drifting incubators for fish that also considers hatching capacity. When guiding the selection of spawning ground restoration sites, this invention not only benefits fish spawning but, more importantly, ensures that fish eggs can survive and hatch during the drifting process, thereby improving the survival rate of fish during the spawning and hatching period. This is of great significance for maintaining regional fish habitats, protecting fish species survival, and protecting biodiversity. Attached Figure Description

[0031] Figure 1 This is a flowchart of a method for calculating the suitability of a spawning ground that takes into account hatching capacity, according to the present invention.

[0032] Figure 2 This is a habitat suitability curve for fish.

[0033] Figure 3 A schematic diagram showing the distribution of habitat suitability in fish spawning grounds during the spawning season;

[0034] Figure 4 A flowchart for refining the habitat model;

[0035] Figure 5 A schematic diagram showing the overall suitability distribution of spawning grounds that take into account both fish hatching capacity and spawning ability. Detailed Implementation

[0036] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings.

[0037] This invention provides a method for calculating the suitability of spawning grounds while taking into account hatching capacity, specifically as follows: Figure 1 As shown, it includes the following steps:

[0038] S1: Select a species of drifting-egg-laying fish from the target area, collect topographic and hydrological data of the drifting-incubation period of the drifting-egg-laying fish in the target area, establish a hydrodynamic model of the target area, and use the hydrodynamic model to simulate the changes in hydrodynamic indicators in the characteristic hydrological year of the region to obtain the habitat factor suitability curve of the drifting-egg-laying fish during the spawning period. The habitat factors include water depth, flow velocity, and water temperature. Step S1 specifically includes:

[0039] (1.1) Select fish species that lay drifting eggs in the target area, monitor and organize data such as the spawning time, spawning site location, spawning site habitat characteristics, and time required for drifting and hatching, and collect topographic and hydrological data of the fish species that lay drifting eggs in the target area during the spawning period and drifting and hatching period;

[0040] (1.2) Establish a hydrodynamic model for the target area, and use the hydrodynamic model to simulate the changes in hydrodynamic indicators during the characteristic hydrological year of the region, so as to obtain the suitable curve of habitat factors during the spawning period of drifting spawning fish.

[0041] Step (1.2) specifically includes:

[0042] (1.2.1) Collect basic data such as underwater topography and hydrological data of the target area, and organize and analyze the characteristic hydrological conditions of each year;

[0043] (1.2.2) The target area is divided into grids to achieve full coverage of the area. Hydrodynamic and water temperature models are used, with the characteristic flow processes of abundant, normal and dry seasons as the inflow boundaries, to calculate the changes in regional flow velocity, water depth and water temperature.

[0044] (1.2.3) Based on the grid and characteristic hydrological year conditions, a hydrodynamic model of the target area is established to simulate the changes in hydrodynamic indicators during the characteristic hydrological year, obtaining the habitat suitability curves for drifting oviparous spawning species, including flow velocity, water depth, and water temperature suitability curves, such as... Figure 2 As shown.

[0045] S2: Based on the suitability curves of habitat factors during the spawning period of the drifting-egg-laying fish, a preliminary habitat model is established; the target area is divided into grids, and each grid is used as a unit. The suitability of the unit's habitat factors is calculated according to the preliminary habitat model as the suitability of the spawning ground during the spawning period, as follows: , , Step S2 specifically includes:

[0046] (2.1) A preliminary habitat model was established using the habitat factor suitability curve and hydrodynamic change process during the fish spawning period as boundaries.

[0047] (2.2) Based on the preliminary habitat model, the suitability of the unit habitat factors was calculated using the fish spawning period suitability curve, as follows: , , (like Figure 2 As shown in the diagram, the suitability distribution of spawning grounds is illustrated in the diagram below. Figure 3 As shown.

[0048] S3: Calculate the suitability of the fish drifting incubator. Step S3 specifically includes:

[0049] (3.1) Calculate the distance between the spawning ground and the nearest water-retaining structure based on the location of the spawning ground and the river flow velocity;

[0050] (3.2) Calculate the time T for fish eggs to drift based on the distance between the spawning ground and the nearest water-retaining structure and the water flow velocity. i ;

[0051] (3.3) The time T for the fish eggs to drift i The time required for the hatching of drifting fish eggs Compare, if T i > This indicates that the fish egg drifting time meets the hatching requirements, and the suitability of the fish drifting incubator is 1; otherwise, the suitability of the fish drifting incubator is 0.

[0052]

[0053] In the formula: Suitability of fish drift incubator; This refers to the distance between the unit and the downstream water-retaining structure. The flow velocity at the unit; This refers to the time required for the hatching of drifting fish eggs. The model can be refined based on a preliminary habitat model; the refinement process is as follows: Figure 4 As shown.

[0054] S4: Based on a comprehensive habitat model, considering both the habitat requirements of spawning grounds during the spawning season and the time requirements of the drifting incubation period, the overall suitability of the spawning grounds is calculated. A schematic diagram of the distribution of spawning grounds and their overall suitability is shown below. Figure 5 As shown.

[0055] Specifically, based on a comprehensive habitat model, taking into account both the spawning ground habitat requirements and the time requirements for drift hatching, the suitability of the fish's spawning ground and drift hatching is multiplied together.

[0056] The overall suitability of the spawning grounds for this fish species is calculated using the following formula:

[0057]

[0058] In the formula: The overall suitability of the spawning grounds for unit i.

[0059] The above-disclosed embodiments are merely preferred embodiments of the present invention and should not be construed as limiting the scope of the invention. Therefore, the present invention is not limited to the above-described optional embodiments. Anyone can derive other products in various forms under the guidance of the present invention. However, regardless of any changes made in their shape or structure, any technical solution that falls within the scope of the claims of the present invention shall be protected within the scope of the present invention.

Claims

1. A method for calculating the suitability of a spawning ground while taking into account hatching capacity, characterized in that... Includes the following steps: S1: Select a species of drifting-egg-laying fish from the target area, collect topographic and hydrological data of the drifting-egg-laying fish during the spawning and drifting-hatching periods in the target area, establish a hydrodynamic model for the target area, and use the hydrodynamic model to simulate the changes in hydrodynamic indicators of the region's characteristic hydrological year to obtain the habitat factor suitability curve for the spawning period of the drifting-egg-laying fish. The habitat factors include water depth, flow velocity, and water temperature. S2: Based on the suitability curves of habitat factors during the spawning period of the drifting-egg-laying fish, a preliminary habitat model is established; the target area is divided into grids, and each grid is used as a unit. The suitability of the unit's habitat factors is calculated according to the preliminary habitat model as the suitability of the spawning ground during the spawning period, as follows: , , ; S3: Calculate the suitability of fish drifting incubators; S4: Multiply the spawning site suitability during the spawning season by the fish drifting incubator suitability to calculate the overall spawning site suitability; Step S3 specifically includes: (3.1) Calculate the distance between the spawning ground and the nearest water-retaining structure based on the location of the spawning ground and the river flow velocity; (3.2) Calculate the time T for fish eggs to drift based on the distance between the spawning ground and the nearest water-retaining structure and the water flow velocity. i ; (3.3) The time T for the fish eggs to drift i The time required for the hatching of drifting fish eggs Compare, if T i > This indicates that the fish egg drifting time meets the hatching requirements, and the suitability of the fish drifting incubator is 1; otherwise, the suitability of the fish drifting incubator is 0. ； In the formula: Suitability of fish drift incubator; This refers to the distance between the unit and the downstream water-retaining structure. The flow velocity at the unit; The time required for the hatching of drifting fish eggs; Step S4 specifically includes: The overall suitability of fish spawning grounds is calculated using the following formula: ； In the formula: Unit i represents the suitability of the spawning grounds while also considering hatching capacity. The overall suitability of the spawning grounds reflects whether the fish habitat in the river is suitable for spawning and also indicates whether the fish eggs in the area can safely hatch and survive.

2. The method according to claim 1, characterized in that, Step S1 specifically includes: (1.1) Select fish species that lay drifting eggs in the target area, monitor and organize data on fish spawning time, spawning site location, spawning site habitat characteristics, and time required for drifting and hatching, and collect topographic and hydrological data of the fish species that lay drifting eggs in the target area during the spawning and drifting and hatching periods; (1.2) Establish a hydrodynamic model for the target area, and use the hydrodynamic model to simulate the changes in hydrodynamic indicators during the characteristic hydrological year of the region, so as to obtain the suitable curve of habitat factors during the spawning period of drifting spawning fish.

3. The method according to claim 2, characterized in that, Step (1.2) specifically includes the following steps: (1.2.1) Collect underwater topographic and hydrological data of the target area, and analyze the characteristic annual hydrological conditions; (1.2.2) The target area is divided into grids to achieve full coverage of the area. The hydrodynamic and water temperature models are used, with the characteristic flow processes of abundant, normal and dry seasons as the inflow boundaries, respectively, to calculate the changes in regional flow velocity, water depth and water temperature. (1.2.3) Based on the grid and characteristic hydrological year conditions, establish a hydrodynamic model for the target area, simulate the change process of hydrodynamic indicators in the characteristic hydrological year of the area, and obtain the habitat factor suitability curves for drifting oviparous spawning periods, including flow velocity, water depth, and water temperature suitability curves.

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