Method for regulating and controlling population quantity of lake coilia ectenes in lake

Abstract

The invention discloses a method for regulating and controlling the population number of lake coilia ectenes in a lake, which comprises the following steps of: increasing the population number of carnivorous fishes such as culter culter and mandarin fish in the lake through the measures of establishing a propagation and proliferation protection area, fishery management and the like; the population biomass of carnivorous fishes (fishes taking the lake coilia ectenes as main baits) such as culter culter and mandarin fish in the lake reaches about 1 / 30 of the population biomass of the lake coilia ectenes; the method comprises the following steps: by establishing a breeding and proliferation protection area and taking measures of fishery management and the like, increasing the population quantity of whitebait in a lake, and enabling the population biomass of whitebait (including protowhitebait and hemisalanx breviscapus) having a bait competition relationship with the coilia ectenes in the lake to reach about 1 / 2 of the population biomass of the coilia ectenes; by adopting measures such as a secondary release mode and fishery management, the population biomass of silver carps and bighead carps having a bait competition relationship with the coilia ectenes in the lake reaches about 1 / 1 of the population biomass of the coilia ectenes. The limitation of a current single fishing means can be made up, so that the diversity of lake biological populations can be effectively improved, and the water area environment can be optimized.

Description

Technical Field

[0001] The present invention relates to the field of aquatic ecology, and in particular to a method for regulating the number of coilia spp. population in lakes. Background Art

[0002] Lake Coilia ectenes taihuensisYuan et Lin belongs to the order Herpetiformes, genus Coilia, also known as knife coilia, knife fish, coilfish, and plum coilia. It is a small, low-value fish in lakes. Due to its high reproduction rate and other reasons, it can easily become an absolutely dominant population in some lakes, which is not conducive to the diversity of fish population structure and the balance of the ecological environment. Taking Taihu Lake as an example: the catch of anchovies was only 2,300-2,400 tons in the 1950s and 1960s, 5,500-7,000 tons in the 1970s and 1980s, and rose to 8,100-12,000 tons in 1990-2000. It increased to 18,000-20,000 tons in 2001-2012, and has increased rapidly since 2013, from 23,800 tons in 2013 to 41,000 tons in 2020. The proportion of anchovies in the catch has also shown an upward trend year by year, from the 1950s to the In the 1980s, the catch of lake coil accounted for about 15% of the total catch, and it increased to about 78% in 2020. It has become the absolutely dominant species in the fish population of Taihu Lake. Excessive lake coil population will have a strong inhibitory effect on economic fish such as silver carp, bighead carp and silver carp in Taihu Lake with the same ecological niche and feeding habits; moreover, since the feeding habits of lake coil are mainly zooplankton such as cladocerans, and zooplankton such as cladocerans use cyanobacteria as bait, the higher biomass of lake coil will inevitably reduce the biomass of zooplankton in the lake area, and thus have an adverse effect on the ecological environment of eutrophication such as controlling cyanobacteria in Taihu Lake. In short, the continuous increase in the number of lake coil populations in lakes has had a significant negative impact on optimizing the fish population structure and the water ecological environment. [1-4]However, there is currently no method for regulating the amount of Coilia spp. in lakes at home and abroad. The existing technology uses a dedicated lake coli trawl tool to conduct a full lake fishing in autumn each year. However, lake coli is a perennial fish that reaches sexual maturity at six months of age, with a large spawning population consisting of fish aged 0-5 years. It also has a long breeding period and can reproduce from April to October when the water temperature is 17-27°C. In addition, the limitations of the mesh size of the fishing nets and the speed of the fishing boats make it impossible to simultaneously capture fish of different age groups with significant differences in body size and swimming speed. During the autumn full lake fishing, only the majority of medium-sized lake coli aged one to two years can be landed, while a large number of small and large lake coli of other age groups remain in the lake. As a result, the lake coli population cannot be controlled by a single fishing method. In addition, excessive fishing intensity has an adverse impact on other economic fish resources in the lake, resulting in a continuous increase in the lake coli population, leading to the miniaturization and devaluation of lake fish, reduced biodiversity, and deterioration of the water environment such as blue-green algae blooms. Based on years of lake ecological investigation and research and lake reproduction and release tracking and monitoring verification, this invention has developed a new method for ecological regulation of lake coil population based on food web and biological manipulation principles. It can make up for the limitations of the current single fishing method, thereby effectively improving the diversity of lake biological populations and optimizing the water environment. Summary of the Invention

[0003] In view of the above problems existing in the prior art, the purpose of the present invention is to provide a method for regulating the population of Coilia spp. in lakes, so as to solve the many problems caused by the shortcomings of the prior art.

[0004] In order to solve the above problems, the technical solutions adopted by the present invention are as follows:

[0005] A method for regulating the amount of Coilia spp. in lakes comprises the following steps:

[0006] (1) Increase the population of carnivorous fish such as silver carp and mandarin fish in lakes

[0007] On sunny days from February to April every year, seedlings of red croaker, mandarin fish and other species are released into the lake area. The seedlings must be large (over 50 grams per fish), healthy, high-quality and in line with the local geographical germplasm, to ensure the survival rate of the released seedlings and the stability of the lake's germplasm resources; a breeding and proliferation protection area for silver carp and mandarin fish is set up to create a natural breeding ground for fish such as red croaker and mandarin fish, and large areas of submerged plants are planted in the coastal micro-flow lake area without human interference, which is conducive to the attachment and hatching of the sticky fertilized eggs produced by silver carp parents; the fishery system is strictly enforced, including: any fishing activities and other production activities are prohibited in the silver carp breeding protection area throughout the year; March to June each year is the closed fishing season for silver carp and mandarin fish, and the fishing age for silver carp must be above 5 years old, and the fishing age for mandarin fish must be above 4 years old, to ensure the stable growth of the breeding and replenishment populations of silver carp and mandarin fish in the lake.

[0008] Through measures such as releasing fish into the lake, establishing breeding and proliferation protection areas, and fishery management, the population biomass of carnivorous fish such as silver carp and mandarin fish (fish that use lake anchovy as their main bait) in the lake has been reduced to about 1 / 30 of the biomass of the lake anchovy population.

[0009] (2) Increase the population of whitebait in lakes

[0010] A breeding and proliferation protection zone for big silverfish and short-nose silverfish will be set up to create a natural breeding ground for big silverfish and short-nose silverfish. The lake bottom will be flat and less silt, which is conducive to the hatching of fertilized silverfish eggs. The fishery system will be strictly implemented, including: any fishing activities and other production activities will be prohibited in the breeding protection zone for big silverfish and short-nose silverfish throughout the year; the catch of silverfish will be postponed to November each year, and a sufficient number of spawning groups should be retained to ensure the steady growth of the breeding and supplementary groups of silverfish in the lake.

[0011] By establishing breeding and proliferation protection areas and fishery management measures, the population biomass of whitebait (including large whitebait and short-nose whitebait) that competes with lake anchovy for food in the lake has reached about 1 / 2 of the lake anchovy population biomass.

[0012] (3) Increase the population of silver carp and bighead carp in lakes

[0013] A two-stage release model is employed: the first year is the first stage, implemented in eutrophic areas of Taihu Lake. Large (5cm) silver carp and bighead carp fingerlings are released in early July each year through cages. These fingerlings are then reared in the cages until December of the same year and harvested annually the following year. For Taihu Lake, for example, the first stage releases 10-15 million silver carp and bighead carp fingerlings. Natural plankton feed is used to cultivate these large fingerlings, reducing release costs and improving the survival rate of released fish. Optimizing the density and location of silver carp and bighead carp in the first stage releases ensures the availability of large-sized fingerlings for the second stage releases. The second year is the second stage release, in which large-sized silver carp and bighead carp fingerlings weighing 90g and 80g, respectively, are released directly into the lake to ensure survival and market quality for the year. By the end of the year, they have reached commercial size and are harvested. The secondary release of silver and bighead carp utilizes the lake's natural plankton resources, requiring no bait or fertilizer. This effectively purifies the water and reduces eutrophication, while also producing large-sized silver and bighead carp fingerlings and commercial fish. During the annual Taihu Lake fishing season, which begins in September, a rotational catch system is used, catching the largest and sparing the smallest. Silver carp and bighead carp must weigh at least 1.5 kg and 2 kg, respectively.

[0014] Through measures such as releasing fish and fishery management, the population biomass of silver carp and bighead carp, which compete with coilia in the lake for bait, has been reduced to about 1 / 1 of the biomass of coilia in the lake.

[0015] All artificially released fish seedlings must use specific genetic molecular markers to identify the germplasm of the lake geographical water system of their place of origin, and must be produced by seedling breeding farms at the provincial level or above and SPF-certified to ensure the stability of the lake's germplasm resources.

Claims

1. A method for regulating the population of Coilia spp. in lakes, characterized in that: The steps include: (1) Increase the population of carnivorous fish such as silver carp and mandarin fish in lakes Through measures such as releasing fish into the lake, establishing breeding and proliferation protection areas, and fishery management, the population biomass of carnivorous fish such as silver carp and mandarin fish (fish that use lake anchovy as their main bait) in the lake has been reduced to about 1 / 30 of the biomass of the lake anchovy population. (2) Increase the population of whitebait in lakes By establishing breeding and proliferation protection areas and fishery management measures, the population biomass of whitebait (including large whitebait and short-nose whitebait) that competes with lake anchovy for food in the lake has reached about 1 / 2 of the lake anchovy population biomass. (3) Increase the population of silver carp and bighead carp in lakes Through measures such as releasing fish and fishery management, the population biomass of silver carp and bighead carp, which compete with coilia in the lake for bait, has been reduced to about 1 / 1 of the biomass of coilia in the lake.

2. A method for regulating the number of Coilia spp. populations in lakes according to claim 1, characterized in that: In the step (1), on sunny days from February to April each year, fry of red croaker, mandarin fish and the like are released into the lake area. The fry are required to be large (50 grams or more per tail), healthy, high-quality and in line with the local geographical germplasm, so as to ensure the survival rate of the released fry and the stability of the lake germplasm resources.

3. A method for regulating the number of Coilia spp. populations in lakes according to claim 1, characterized in that: In the step (1), a breeding and proliferation protection area for silver carp and mandarin fish is set up to create a natural breeding ground for fish such as red croaker and mandarin fish. Large areas of submerged plants are planted in the coastal micro-flow lake area without human interference, which is conducive to the attachment and hatching of sticky fertilized eggs produced by silver carp parents.

4. A method for regulating the number of Coilia spp. populations in lakes according to claim 1, characterized in that: In the step (1), the fishing system is strictly implemented, including: any fishing activities and other production activities are prohibited in the breeding protection area of ​​the croaker throughout the year; March to June each year is the closed fishing season for croaker and mandarin fish, and the fishing age of croaker must be above V years old, and the fishing age of mandarin fish must be above IV years old.

5. A method for regulating the number of Coilia spp. populations in lakes according to claim 1, characterized in that: In the step (2), a breeding and proliferation protection zone for large whitebait and short-nose whitebait is set up to create a natural breeding ground for large whitebait and short-nose whitebait. The lake bottom is flat and less silt, which is conducive to the hatching of whitebait fertilized eggs.

6. A method for regulating the number of Coilia spp. populations in lakes according to claim 1, characterized in that: In step (2), the fishing system is strictly implemented, including: any fishing activities and other production activities are prohibited in the breeding protection areas of big whitebait and short-nose whitebait throughout the year; the whitebait harvest is postponed to November each year, and a sufficient number of spawning groups should be retained to ensure the stable growth of the breeding population and supplementary population of whitebait in the lake.

7. The method for regulating the number of Coilia spp. population in lakes according to claim 1, wherein: In step (3), a two-stage release model is adopted: the first year is the first-stage release, which is implemented in the eutrophic area of Taihu Lake. By setting up cages, large-sized (5cm) silver carp and bighead carp summer flower fingerlings are released in early July each year, and the cages are cultivated until December of the same year and the large-sized fish are harvested annually in the following year. Taking Taihu Lake as an example, the first-stage release of silver carp and bighead carp summer flower fingerlings totals 10-15 million. Natural plankton bait is used to cultivate large-sized fish fingerlings, thereby reducing the release cost and improving the survival rate of the released fish. By optimizing the density and location of silver carp and bighead carp released in the first stage, the needs of large-sized silver carp and bighead carp fingerlings released in the second stage are met. The second year is the second-level stocking phase, where silver carp and bighead carp weighing 90g and 80g, respectively, are released directly into the lake's entirety to ensure survival and marketable quality. By the end of the year, they are harvested when they reach commercial size. This second-level stocking utilizes the lake's natural plankton resources, without the use of bait or fertilizer. This effectively purifies the water and reduces eutrophication, while also producing large-sized silver carp and bighead carp fingerlings and commercial fish.

8. The method for regulating the number of Coilia spp. population in lakes according to claim 1, wherein: In the step (3), after September of each year during the Taihu Lake fishing season, a rotation fishing method of catching the big ones and leaving the small ones is adopted to catch silver carp and bighead carp whose weight must be above 1.5 kg and 2 kg respectively.