Method for constructing multiple habitats for fish in nest-shaped habitats

Abstract

The present invention discloses a nest-shaped fish habitat multi-habitat construction method, the method comprising: constructing a plurality of nest-shaped habitat areas in a target fish habitat construction area, each of the nest-shaped habitat areas comprising a gravel substrate, a pebble substrate laid on the gravel substrate, and a plant substrate laid on the pebble substrate; the layout areas of the gravel substrate, the pebble substrate, and the plant substrate decrease in sequence, and along the direction of water flow, a nesting pattern of a single pebble substrate, a pebble substrate nested in a gravel substrate, a pebble substrate nested in a gravel substrate and a plant substrate, a pebble substrate nested in a gravel substrate, and a single pebble substrate is formed. The present invention constructs a transitional change in the substrate through layer-by-layer nesting of different substrates, forms a habitat substrate distribution pattern with greater structural heterogeneity, and is supplemented by the growth cycle change law of aquatic plants, so as to meet the multi-habitat requirements of fish at various stages.

Description

Technical Field

[0001] The invention relates to a method for constructing a nest-shaped fish habitat multi-habitat. Background Art

[0002] In recent years, while water conservancy and hydropower projects have played a comprehensive role in flood control, power generation, and shipping, they have also had a certain impact on the ecological environment. The connectivity of aquatic habitats is blocked by dams and gates, causing the decline of migratory fish populations. At the same time, it will also change the natural hydrological situation upstream and downstream, causing the weakening of river stimulation conditions and the decline in fish reproduction. In the context of the era of "ecological priority and green development", taking the reconstruction of fish habitats as the goal and shaping a suitable environment for natural reproduction is an important means to follow the physiological needs of fish and alleviate the adverse effects of water conservancy projects.

[0003] The existing protection and restoration of fish habitats mostly adopts single engineering measures, such as laying out cylinders, rocks, etc. or ecological fishways in the habitat to improve the flow pattern of water to ensure the survival and migration of fish. However, the protection period and water flow conditions are limited and cannot cover all stages of fish growth and development, spawning, wintering, and feeding, thus limiting the scope of protection. Patent CN11254891B proposes a method for arranging rocks in ecological fishways suitable for the four major carps. It adds rocks of different arrangements in the river channel to reduce water flow energy, reduce water flow velocity, and provide a migratory channel. However, this method only meets the needs of fish in the migratory stage and ignores the needs of fish in other stages.

[0004] Riverbed sediments are an important factor in determining the biological structure of habitats. Unreasonable sediment composition and distribution will lead to habitat reduction, thereby reducing the number and diversity of organisms in the habitat. Summary of the invention

[0005] Purpose of the invention: The present invention aims to solve the problem that existing fish habitats cannot meet the water flow conditions and living places required for the reproduction, growth and development of fish in various stages of the cycle, and provides a method for constructing nested fish habitats.

[0006] Technical solution: The nest-type fish habitat multi-habitat construction method described in the present invention comprises: constructing multiple nest-type habitat areas within the area of ​​the target fish habitat construction area, each of the nest-type habitat areas comprising a sandy gravel substrate, a pebble substrate laid on the sandy gravel substrate, and a plant substrate laid on the pebble substrate; the layout areas of the sandy gravel substrate, the pebble substrate, and the plant substrate decrease in sequence, and along the direction of water flow, a nesting pattern of a single pebble substrate, a pebble substrate nested in a sandy gravel substrate, a pebble substrate nested in a sandy gravel substrate and a plant substrate, a pebble substrate nested in a sandy gravel substrate, and a single pebble substrate is formed.

[0007] The sand and gravel substrate, pebble substrate and plant substrate are all arranged in a rectangular shape.

[0008] The above method specifically comprises the following steps:

[0009] (1) Based on the growth and reproduction habits of the target fish and the geographical location and natural conditions of their habitats, data surveys and collections are conducted, and the scope of the habitat construction area is determined based on the flow, velocity, water level data of the target fish habitat construction area and the reproduction, growth, development, and migration characteristics of the fish;

[0010] (2) According to the characteristics of the target fish during spawning, overwintering and feeding, the habitat construction area is divided into multiple nesting habitat areas. Plant substrate, pebble substrate and gravel substrate are arranged in each nesting habitat area, and the layout areas of plant substrate, pebble substrate and gravel substrate increase in sequence;

[0011] (3) The substrate is nested and combined in an increasing or decreasing manner according to the substrate layout area, forming multiple U-shaped nesting habitat areas within the target fish habitat construction area to meet the needs of fish at different stages.

[0012] In step (1), data survey and collection are conducted, and the data content includes hydrological data, runoff data, riverbed matrix data, target fish growth and habitat data, and aquatic plant data within the fish habitat construction area; the hydrological data include the multi-year average flow and average water level data of the habitat construction area; the meteorological data include rainfall and temperature data; the fish growth and habitat data include the hydrodynamic data suitable for the growth and reproduction of each fish species; the aquatic plant data include the relationship data between different types of aquatic plants in the fish habitat construction area and the water flow characteristics and the growth rate table of aquatic plants at various stages.

[0013] In step (1), the scope of the fish habitat construction area is calculated using the following formula:

[0014]

[0015] Where: S is the area of ​​the region; μ S is the flow correction coefficient; Q max The maximum flow rate suitable for target fish; Q min Minimum flow suitable for target fish; is the average annual flow rate of the region; is the regional annual average flow velocity; is the average annual water depth of the region; n s is the river channel roughness; U min The minimum flow velocity suitable for target fish; U max is the maximum flow velocity suitable for fish; ε is the flow velocity correction coefficient; are water depth correction factors respectively.

[0016] Wherein, in step (2), the area and area ratio of the plant substrate, gravel substrate, and pebble substrate arranged in each nested habitat area are calculated using the following formulas:

[0017] S z =(β z +α z )S

[0018] S s =(2β s +4α s )2S

[0019]

[0020] (i=z, s, l; j=z, s, l and i≠j)

[0021] Where: s z 、s l 、s s are the areas of plant substrate, gravel substrate and pebble substrate respectively; γ i is the area ratio of the substrate corresponding to i; α z , α s , α l are the corresponding sediment flow velocity correction weights; β z , β s , β l are the corresponding bottom depth correction weights; z, s, l represent the plant bottom, sand and gravel bottom, and pebble bottom numbers respectively;

[0022] Nesting mode: When γ i >1, then s i Internal nesting j ; When γ i When <1, it is s j Internal nesting i .

[0023] In step (2), the length and width of the plant substrate, gravel substrate, and pebble substrate layout areas are calculated using the following formulas:

[0024]

[0025]

[0026] (i=z、s、l)

[0027] Where: d xi is the width of the substrate layout corresponding to i; d yiis the length of the substrate layout corresponding to i; z, s, l represent the numbers of plant substrate, gravel substrate, and pebble substrate respectively; τ i is the area correction coefficient, which is determined according to the fish species. When the fish species is determined, the corresponding correction coefficient is determined; s i is the area of ​​the substrate corresponding to i.

[0028] Wherein, in step (2), the aquatic plants planted in the plant substrate are narcissus, duckweed, water hyacinth, canna, calamus and / or Vallisneria; in the nesting habitat area suitable for the target fish to spawn, the aquatic plants are arranged in a V-shaped staggered and cross-planted, so that the water flows in a winding way, forming a curved water flow, and the water flow produces a turbulent flow state, thereby stimulating the spawning behavior of fish, and the aquatic plant roots provide attachment points for fish to spawn. The selection of aquatic plants is based on the growth cycle characteristics of aquatic plants and the various growth and development stages of fish. The growth habits of fish at all stages can be adaptively matched at all stages of plant growth.

[0029] Wherein, in step (2), the gravel substrate is composed of fine gravel with a particle size of 2 to 10 mm, coarse gravel with a particle size of 10 to 100 mm, and giant gravel with a particle size greater than 100 mm, and the mixed volume ratio of fine gravel, coarse gravel and giant gravel is 3:2:1.

[0030] Among them, in step (2), the pebble substrate is a mixture of pebbles with a particle size of 60 to 100 mm, pebbles with a particle size of 100 to 150 mm and pebbles with a particle size of 150 to 200 mm in a volume ratio of 1:1:1, and the pebble size ratio used is complementary to the gravel size ratio.

[0031] Among them, the growth rate of the selected aquatic plants is calculated based on the growth rate of the corresponding fish in the nesting habitat area and the growth parameters of the aquatic plants, with the parameters of plant height, leaf area, root length and canopy height. The characteristics of the plant growth stage are matched with the habits of the target fish at each stage. Based on the natural law of plant growth, the needs of the growth and breeding stages of the target fish are met to form a complete and good ecosystem. The specific calculation formula is as follows:

[0032]

[0033] Where: θ s , θ1, θ2, θ3 are plant growth correction coefficients respectively; h s is the plant height; a is the leaf area; RT -1 is the root-to-crown ratio; t is the growth time of the fish in the i-th stage; u si is the growth rate of fish in the i-th stage; v s is the growth rate of aquatic plants (the above formula is the growth rate of target aquatic plants); based on the calculated plant growth rate v sConsult the table to select appropriate aquatic plants to meet the needs of target fish at various stages.

[0034] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages: the complex water flow conditions such as turbulence and vortex formed by the gravel bottom, pebble bottom and plant bottom of the present invention can increase the oxygen content in the water flow. At the same time, the gravel bottom and pebble bottom can also provide an open water flow area for young fish, and the plant bottom provides spawning attachment points, food supplies and hiding places for fish during spawning. The present invention nests different bottoms layer by layer to construct transitional changes in the bottom, forming a habitat bottom distribution pattern with greater structural heterogeneity. At the same time, it is supplemented by the growth cycle changes of aquatic plants to meet the multi-habitat needs of fish at various stages. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 A flow chart of the method for constructing the present invention;

[0036] Figure 2 It is a schematic diagram of the nested multi-habitat of the present invention;

[0037] Figure 3 Schematic diagram of three nested substrates of the present invention;

[0038] Figure 4 Schematic diagram of nested layout of nested areas of the present invention

[0039] Figure 5 This is a schematic diagram of the entire fish multi-habitat construction constructed by the present invention. DETAILED DESCRIPTION

[0040] like Figure 2 As shown, it is a schematic diagram of the nested multi-habitat of the present invention. The three substrates are combined layer by layer in a U-shaped nesting manner, providing transitional changes and substrate areas with large structural heterogeneity for the growth, development, reproduction, spawning, and overwintering stages of fish, thereby meeting the needs of fish at various stages.

[0041] like Figure 3 As shown, there are three kinds of bottom material schematic diagrams of the present invention. Sandstone bottom material, pebble bottom material and plant bottom material are arranged in the nested habitat area. The complex water flow conditions such as turbulence and vortex formed by the nested combination of the three kinds of bottom materials can increase the oxygen content in the water flow, stimulate the reproduction behavior of adult fish, and provide a hiding place for fish during spawning. At the same time, stones are beneficial for young fish to maintain an open water flow area. In the nested habitat area, plants are arranged in a V-shaped staggered manner and cross-planted, so that the water flow flows in a meandering manner, forming a bend water flow, causing the water flow to produce a turbulent flow state, and mixing the water flow of different water temperature layers, alleviating the damage of low-temperature water at the bottom of the river to fish, thereby stimulating fish spawning behavior, and the plant roots provide attachment points for fish spawning.

[0042] like Figure 4As shown in the figure, in each nest habitat area, the layout width d of each substrate xi , length d yi The layout area ratio of each bottom type is determined based on the area of ​​the habitat construction, the average water depth over many years, flow rate, and the flow velocity preferred by the target fish.

[0043] like Figure 5 As shown, it is a schematic diagram of the entire fish multi-habitat constructed by the present invention. In the target fish habitat construction area, a plurality of U-shaped nest habitat areas are arranged, which meet the requirements of growth, reproduction and migration of target fish at various stages, and form a full-stage multi-habitat habitat that meets the needs of target fish within the habitat.

[0044] Taking a tributary section in a basin where the four major carps live as an example, the main fish species in this section are black carp, grass carp, silver carp and bighead carp. The hydrodynamic, hydrological, meteorological, geological and geomorphological data of the basin in the past 20 years, the living habits of the four major carps at each growth stage, the preferred water temperature, spawning location, suitable flow velocity range, and the relationship between the growth cycle of each fish and the growth rate of aquatic plants were collected. It was found that the preferred flow velocity range of various four major carps is 0.9-1.5m / s, and the lower limit flow velocity for fish egg drifting and hatching is 0.25m / s; after 106-139h of the development period, the fish eggs develop into young fish that can actively swim; the water temperature cannot be lower than 18℃ when the four major carps reproduce, and the most suitable water temperature is 20-24℃; the water temperature range for domestic fish embryonic development is 18℃-30℃, and the suitable water temperature is 22℃-28℃.

[0045] The range of the habitat area is determined based on the average flow and average water depth of the habitat construction area of ​​the four major carps in the river. The parameter d of the nest habitat area is xi ,d yi At the same time, the nesting method of the nesting habitat area and the selection of aquatic plants are determined according to the hydrodynamic conditions of the habitat construction area, plant growth parameters, and the needs of the four major carps at various stages. The results of various parameters of the fish multi-habitat construction area are as follows:

[0046] Table 1 Results of various indicators in the construction area of ​​multiple habitats for the four major carps

[0047]

[0048]

[0049] According to the calculated plant growth cycle rate, the appropriate plants are selected by looking up the table. The aquatic plants selected in this nesting habitat area are water hyacinth and canna. During the spawning period, the four major carps will choose areas with sand and gravel and rough pebbles to ensure that the eggs produced are eaten by other animals and sufficient oxygen is required during the hatching process; if it is in the dry season, they will choose to spawn on sandy beaches or pebble beaches exposed to the water surface, and the bottom is mainly a combination of sand and gravel and pebbles; during the development stage of fish eggs, they need to experience the undulating riverbed and hatch under the action of special water dynamics such as "upwelling", "downwelling" and "vortex". The constructed sand and gravel bottom-pebble bottom-sand and gravel pebble nested bottom combination habitat provides favorable conditions for the movement and hatching of fish eggs; at the same time, plant bottom can also play a vital role in the growth of fish fry and juveniles. Adequate plant bottom provides shelter and food sources for fry and juveniles, effectively improving the survival rate of fry and juveniles in the river.

[0050] Later, the growth of the four major carps in the habitat area was tracked and investigated and analyzed. After 100 days, it was monitored that the number of occurrences of the four major carps in the habitat construction area increased, the number of black carp fry increased by 10%, the spawning area locations increased from the original 2 to 7, among which the grass carp spawned the most; the growth rates of the four fish species also increased by 16%; through the full-stage multi-habitat construction method for the four major carps of the present invention, the survival rate of the four major carps in the habitat is guaranteed, and the balance of the growth and development stages of the four major carps in the habitat is maintained.

[0051] The nest-shaped fish multi-habitat domain constructed by the present invention meets the requirements of growth and reproduction, migration, overwintering, spawning and foraging of target fish at various stages. The gravel bottom and pebble bottom provide open water flow areas for young fish, and the plant bottom also provides spawning attachment points, food supplies and hiding places for fish during spawning. The nested combination of the three bottoms restores the natural ecological environment, improves adverse water flow conditions, balances the species richness of fish in the habitat, and achieves the goal of ecologically friendly development.

Claims

1. A method for constructing a nest-shaped fish habitat, characterized in that: The method comprises: constructing a plurality of nested habitat areas in a target fish habitat construction area, each of the nested habitat areas comprising a sandstone substrate, a pebble substrate laid on the sandstone substrate, and a plant substrate laid on the pebble substrate; the layout areas of the sandstone substrate, the pebble substrate, and the plant substrate decrease in sequence, and along the water flow direction, a nesting pattern of a single pebble substrate, a pebble substrate nested in a sandstone substrate, a pebble substrate nested in a sandstone substrate and a plant substrate, a pebble substrate nested in a sandstone substrate, and a single pebble substrate is formed; The above method specifically comprises the following steps: (1) Based on the growth and reproduction habits of the target fish and the geographical location and natural conditions of their habitats, data surveys and collections are conducted, and the scope of the habitat construction area is determined based on the flow, velocity, water level data of the target fish habitat construction area and the reproduction, growth, development, and migration characteristics of the fish; Among them, the scope of the fish habitat construction area is calculated using the following formula: Where: S is the area of ​​the region; μ S is the flow correction coefficient; Q max The maximum flow rate suitable for target fish; Q min Minimum flow suitable for target fish; is the average annual flow rate of the region; is the regional annual average flow velocity; is the average annual water depth of the region; n s is the river channel roughness; U min The minimum flow velocity suitable for target fish; U max is the maximum flow velocity suitable for fish; ε is the flow velocity correction coefficient; are water depth correction factors respectively; (2) According to the characteristics of the target fish during spawning, overwintering and feeding, the habitat construction area is divided into multiple nesting habitat areas. Plant substrate, pebble substrate and gravel substrate are arranged in each nesting habitat area, and the layout areas of plant substrate, pebble substrate and gravel substrate increase in sequence; (3) The substrate is nested and combined in an increasing or decreasing manner according to the substrate layout area, forming multiple U-shaped nesting habitat areas within the target fish habitat construction area to meet the needs of fish at different stages.

2. The method for constructing a nest-shaped fish habitat according to claim 1, characterized in that: The sandstone substrate, the pebble substrate and the plant substrate are all arranged in a rectangular shape.

3. The method for constructing a nest-shaped fish habitat according to claim 1, characterized in that: In step (1), data survey and collection are conducted, and the data content includes hydrological data, runoff data, riverbed matrix data, target fish growth and habitat data and aquatic plant data within the fish habitat construction area; the hydrological data include the multi-year average flow and average water level data of the habitat construction area; the meteorological data include rainfall and temperature data; the fish growth and habitat data include the hydrodynamic data suitable for the growth and reproduction of each fish species; the aquatic plant data include the relationship data between different types of aquatic plants in the fish habitat construction area and the water flow characteristics and the growth rate table of aquatic plants at various stages.

4. The method for constructing a nest-shaped fish habitat according to claim 1, characterized in that: In step (2), the area and area ratio of the plant substrate, gravel substrate, and pebble substrate arranged in each nest habitat area are calculated using the following formulas: S z =(β z +a z )S S s =(2b s +4a s )2S Where: s z 、s l 、s s are the areas of plant substrate, gravel substrate and pebble substrate respectively; γ i is the area ratio of the substrate corresponding to i; α z , α s , α l are the corresponding sediment flow velocity correction weights; β z , β s , β l are the corresponding bottom depth correction weights; z, s, l represent the plant bottom, sand and gravel bottom, and pebble bottom numbers respectively; Nesting mode: When γ i >1, then s i Internal nesting j ; When γ i When <1, it is s j Internal nesting i .

5. The method for constructing a nest-shaped fish habitat according to claim 1, characterized in that: In step (2), the length and width of the plant substrate, gravel substrate, and pebble substrate layout areas are calculated using the following formulas: Where: d xi is the width of the substrate layout corresponding to i; d yi is the length of the substrate layout corresponding to i; z, s, l represent the numbers of plant substrate, gravel substrate, and pebble substrate respectively; τ i is the area correction factor, which is determined according to the fish species; s i is the area of ​​the substrate corresponding to i.

6. The method for constructing a nest-shaped fish habitat according to claim 1, characterized in that: In step (2), the aquatic plants selected as the plant substrate are narcissus, hornwort, water hyacinth, canna, calamus and / or Vallisneria; the growth rate of the selected aquatic plants is calculated based on the growth rate of the corresponding fish in the nested habitat area and the aquatic plant growth parameters, with plant height, leaf area, root length and canopy height parameters, and the plant growth stage characteristics are matched with the habits of the target fish at each stage. Based on the natural law of plant growth, the needs of the target fish growth and breeding stages are met to form a complete and good ecosystem. The specific calculation formula is as follows: Where: θ s , θ1, θ2, θ3 are plant growth correction coefficients respectively; h s is the plant height; a is the leaf area; RT -1 is the root-to-crown ratio; t is the growth time of the fish in the i-th stage; u si is the growth rate of fish in the i-th stage; v s To calculate the corresponding growth rate of aquatic plants; based on the calculated plant growth rate v s Consult the table to select appropriate aquatic plants to meet the needs of target fish at various stages.

7. The method for constructing a nest-shaped fish habitat according to claim 1, characterized in that: In step (2), the gravel substrate is a mixture of fine gravel with a particle size of 2 to 10 mm, coarse gravel with a particle size of 10 to 100 mm, and giant gravel with a particle size of more than 100 mm.

8. The method for constructing a nest-shaped fish habitat according to claim 1, characterized in that: In step (2), the pebble substrate is a mixture of pebbles with a particle size of 60 to 100 mm, pebbles with a particle size of 100 to 150 mm, and pebbles with a particle size of 150 to 200 mm.

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