Method for protecting early fish resources

Abstract

The invention provides a method for protecting early fish resources, and belongs to the technical field of aquatic organism resource protection. The method comprises the following steps: collecting and arranging breeding habits of to-be-protected fishes, and mastering hydrological conditions; collecting roes through the Jiang net in good time and metering; carrying out in-situ concentrated artificial incubation; in-situ concentrated fry breeding in the larval and juvenile fish stage; variety identification and metering; releasing is conducted; fish resource monitoring is carried out, and fish population quantity and structure change are fed back. The method solves the problem that fishes laying drifting eggs cannot complete embryonic development and larval fish development due to the fact that the length of a flowing river section is too short due to construction of a hydropower station, and achieves the technical effects of improving and protecting the survival rate of early resources of target fishes and protecting and proliferating fish resources and fishery resources.

Description

Technical Field

[0001] The invention belongs to the technical field of aquatic biological resource protection, and in particular relates to a method for protecting early fish resources. Background Art

[0002] Fish that lay drifting eggs usually have a large number of eggs and lay a large number of eggs. For example, the four major carps can lay up to one million eggs per parent. However, in the natural state, due to the presence of a large number of organisms that swallow fish eggs and prey on fish fry, the survival rate of fish embryos and fry is very low. According to relevant literature, the survival rate of fish eggs to fry in nature is only about 1%.

[0003] The dams built for hydropower development on the main and tributary rivers have caused the connectivity and fluidity of rivers to deteriorate, posing a major threat to the survival of fish, especially those with drifting spawning ecological types. After the cascade development of hydropower in rivers, there are still some or newly formed fish spawning grounds. Some fish that lay drifting eggs will spawn and reproduce in the flowing river sections. However, since the length of the flowing river section is not enough to meet the development process of fish embryos and fry, a large number of fish eggs or fry sink to the bottom of the water and die, which seriously threatens fish biological resources. According to previous artificial breeding experience, the survival rate of fish eggs and fry can be improved by artificial hatching; however, in the face of macro fish resources in a complex natural environment, appropriate and effective artificial intervention measures are taken to achieve large-scale protection, and there is a lack of mature and feasible technical solutions in the existing technology. Summary of the invention

[0004] The technical problem to be solved by the present invention is: for fish that produce drifting eggs in the natural environment, what kind of intervention measures can be taken to achieve large-scale protection.

[0005] In order to achieve the above technical objectives, the present invention adopts the following technical solutions:

[0006] A method for protecting early fish resources, comprising: during the spawning period of the protected target fish, setting a trap downstream of the spawning ground to collect naturally produced fish eggs, collect and measure them, and count the number of early fish resources; concentrating the collected fish eggs in an incubation facility built in situ for hatching and cultivation, and sampling, and performing species identification by morphology or DNA sequencing to obtain the proportion of the number of various fish; when the fry are cultivated to the stage where the yolk sac is completely absorbed and they can swim horizontally and actively feed, they are counted and released into the original river; or they are cultivated to larger sizes according to the needs of protection and then released; and then the fish resources are continuously monitored, and the number of fertilized eggs collected and the number of fry released is adjusted according to the changes in the population structure and quantity.

[0007] Preferably, before collecting the naturally produced fish eggs, the breeding habits and hydrological conditions of the target fish species to be protected in the implementation area are collected.

[0008] Preferably, the trap net and in situ constructed hatchery and breeding facilities are prepared in advance before the breeding season.

[0009] Preferably, the mesh opening area of ​​the trap is 1% of the river width × 2 m.

[0010] Preferably, for the river section where the collection section is downstream of the spawning ground and the flow velocity is greater than 0.3 to 0.5 m / s, a multi-layered trap net is set up.

[0011] As a preferred method, the hatching facility is driven directly by the in-situ water body after being filtered through a 60-mesh filter, and 0.1m is provided for every 100,000 eggs. 3 Hatchery facility capacity; fry and seedling cultivation is completed in hatchery facilities.

[0012] Preferably, the time point for collecting fish eggs with the trap net is the natural spawning and breeding season of the target fish each year.

[0013] Preferably, during the collection process, the net is checked every 120 minutes from 20:00 to sunrise the next day, and every 240 minutes in the remaining time range, and eggs are collected immediately after being found; when egg signals occur, the eggs are collected every 30 minutes.

[0014] Preferably, after the fry are hatched out of the membrane, they are continuously cultivated in the hatching bucket until the fry swim horizontally and ingest food.

[0015] Preferably, the breeding habits include breeding season, spawning location, spawning amount, fertilization method, parent fish behavior, breeding strategy, and environmental adaptability; the hydrological conditions include water temperature, flow rate, dissolved oxygen in water, sand content in water, transparency, pH value, salinity, water level, and conductivity.

[0016] In the present invention, the in-situ hatchery facilities refer to hatchery facilities built on the local site; the in-situ water body refers to the water body on the site, that is, the river water or river water where the fish eggs are located when the fish eggs are collected. The adjustment of the number of fertilized eggs collected according to the changes in population structure and quantity refers to the timely reduction of the number of fishing nets when the target protected fish resources recover and increase, and the increase of fishing nets when the target protected fish resources recover and increase. This is hereby explained.

[0017] The present invention provides a method for protecting early fish resources, and belongs to the technical field of aquatic biological resource protection. The method comprises: collecting and collating fish breeding habits (including breeding season, spawning location, spawning amount, fertilization mode, parent fish behavior, breeding strategy and environmental adaptability, etc.), mastering hydrological conditions (including water temperature, flow rate, dissolved oxygen in water body, sand content in water body, transparency, pH value, salinity, water level and conductivity, etc.); timely collecting fish eggs through fishing nets and measuring them; in-situ centralized artificial hatching; in-situ centralized seedling cultivation of fry and juvenile fish; species identification and measurement; release; carrying out fish resource monitoring, and feedback on fish population quantity and structural changes. The present invention solves the problem that due to the construction of hydropower stations, the length of the flowing river section is too short, resulting in the inability of fish laying drifting eggs to complete embryonic development and fry and juvenile development, and achieves the technical effect of improving the survival rate of early fish resources and protecting fish resources and fishery resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a flow chart of the method of the present invention.

[0019] Figure 2 This is the first working photo of the present invention in the research stage, showing the assembly process of the dart net.

[0020] Figure 3 This is the second working photo of the present invention in the research stage, showing the state of the fishing net collecting fish eggs in rivers. DETAILED DESCRIPTION

[0021] The specific embodiments of the present invention will be described in detail below. In order to avoid too much unnecessary details, the well-known structures or functions will not be described in detail in the following examples. The approximate language used in the following examples can be used for quantitative expression, indicating that the quantity can be allowed to have a certain change without changing the basic function. Unless otherwise defined, the technical and scientific terms used in the following examples have the same meaning as those generally understood by those skilled in the art to which the present invention belongs.

[0022] Through investigation, it was found that fish with drifting eggs spawned in a certain reservoir area. The survival rate of fish after natural spawning in the original flowing river section was less than 1%. Due to the water storage of the downstream dam, the distance of the flowing river section was only 80km. The specific gravity of drifting fish eggs was slightly greater than that of water. When the water flow speed was lower than 0.25m / s, they would sink to the bottom of the water, lack of oxygen or being squeezed by water pressure, leading to death.

[0023] During the breeding season of drifting fish eggs, the fertilized eggs of naturally spawning fish in the river are continuously collected through the nets in the river section with a flow rate of 0.3-0.5m / s in the reservoir area from May to June every year. The area of ​​the net is 1% of the river width × 2m. Check once every 240 minutes during the day and once every 120 minutes after 8 o'clock. If eggs are found, collect them in time. When egg signal occurs, collect them every 30 minutes and move the fertilized eggs to the hatching bucket for hatching in time. The volume of each hatching bucket is 0.1m 3 , can incubate 100,000 fertilized eggs at the same time.

[0024] Using river water filtered through 60 meshes to directly supply water to the hatching bucket can ensure constant water temperature and provide suitable bait for the fry. The artificial hatching method can significantly increase the survival rate of fish fertilized eggs to 90% due to the reduction of predators and natural losses.

[0025] After 25 to 30 hours of incubation, the fry will continue to be cultivated in the incubation bucket after they emerge from the membrane. After 48 to 72 hours, the fry will swim horizontally and eat. They can be released or continued to be cultivated as needed.

[0026] By collecting 1% of naturally produced fertilized eggs and improving the survival rate of hatching and seedling cultivation, the natural loss in nature is compensated and the purpose of protecting early fish resources is achieved.

[0027] Continuously monitor changes in fish resources and use feedback data to adjust the number of fishing nets to regulate fish populations.

[0028] The embodiments of the present invention are described in detail above, but the contents are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the scope of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for protecting early fish resources, characterized in that: include: During the spawning period of the target fish species, traps are set up downstream of the spawning grounds to collect and measure naturally produced fish eggs, and count the number of early fish resources; The collected fish eggs are concentrated in the incubation facilities built on site for hatching, cultivation and sampling, and species identification is carried out through morphology or DNA sequencing to obtain the proportion of various fish populations. When the fry are cultivated to the stage where the yolk sac is completely absorbed and they can swim horizontally and actively feed, they are counted and released into the original river. Or they are cultivated to larger sizes according to the needs of protection and then released. Fish resources are then continuously monitored, and the number of fertilized eggs collected and fry released is adjusted according to changes in population structure and quantity.

2. A method for protecting early fish resources according to claim 1, characterized in that: Before collecting the naturally produced fish eggs, the reproductive habits and hydrological conditions of the target fish species to be protected in the implementation area are collected.

3. A method for protecting early-stage target fish resources according to claim 1, characterized in that: The nets and in-situ hatchery and breeding facilities are prepared in advance before the breeding season.

4. A method for protecting early fish resources according to claim 1, characterized in that: The opening area of ​​the trap is 1% of the river width × 2m.

5. A method for protecting early fish resources according to claim 1, characterized in that: For the river section where the collection section is downstream of the spawning ground and the flow velocity is greater than 0.3-0.5m / s, a multi-layered net is set up.

6. A method for protecting early fish resources according to claim 1, characterized in that: The hatching facility is directly driven by the in-situ water body after being filtered through a 60-mesh filter. Every 100,000 fish eggs are equipped with 0.1m 3 Hatchery facility capacity; fry and seedling cultivation is completed in hatchery facilities.

7. A method for protecting early fish resources according to claim 1, characterized in that: The time point for collecting fish eggs with the trap net is the natural spawning and breeding season of the target fish every year.

8. A method for protecting early fish resources according to claim 1, characterized in that: During the collection process, the nets are checked every 120 minutes from 20:00 to before sunrise the next day, and every 240 minutes in the remaining time range. If eggs are found, they are collected immediately; when egg signals occur, they are collected every 30 minutes.

9. A method for protecting early fish resources according to claim 1, characterized in that: After the fry hatch out of the membrane, continue to cultivate them in the hatching bucket until they can swim horizontally and eat.

10. A method for protecting early fish resources according to claim 2, characterized in that: The breeding habits include breeding season, spawning location, spawning quantity, fertilization method, parent fish behavior, breeding strategy, and environmental adaptability; the hydrological conditions include water temperature, flow rate, dissolved oxygen in water, sand content in water, transparency, pH value, salinity, water level, and conductivity.

Images