Method for improving aquatic ecological environment by inhibiting population number of invasive fishes

Abstract

The invention provides a method for improving an aquatic ecological environment by inhibiting the population number of invasive fishes, which comprises the following steps: judging whether the invasive fishes influence the biodiversity and aquatic economy of local native species, if so, locally selecting indigenous fishes according with specified conditions, and if not, selecting the indigenous fishes according with the specified conditions; as an ontology for inhibiting fish invasion and promoting fishery yield and efficiency increase; continuously feeding the native fish with the selected invasive fish as at least a portion of the feed; and determining the improvement effect of the aquatic ecological environment to be improved according to the population descending quantity of the invading fishes. According to the method, the invasive fishes are used as feed to feed the indigenous fishes, the population number of the invasive fishes can be gradually inhibited, so that the influence of the invasive fishes on the biodiversity of local indigenous species and aquatic economy is improved, and the inhibition amount of the invasive fishes is in direct proportion to the improvement effect of the aquatic ecological environment, so that the effect of improving the aquatic ecological environment is achieved. Along with the continuous reduction of the population number of invading fishes, the aquatic ecological environment is inevitably improved.

Description

Technical Field

[0001] The invention relates to an environment improvement method, in particular to a method for improving aquatic ecological environment by suppressing the population of invasive fish. Background Art

[0002] According to the CBD (Convention of Biological Diversity), invasive alien species refer to alien species whose introduction and / or spread threatens biodiversity. According to the Measures for the Management of Invasive Alien Species, invasive alien species refer to alien species that are introduced and colonized and threaten or harm ecosystems, habitats, species, affect my country's ecological environment, and damage the sustainable development of agriculture, forestry, animal husbandry and fishery and biodiversity. From the meaning of invasive alien species and quarantine pests, invasive alien species mainly threaten "biodiversity", and more attention is paid to their possible threats to ecosystems, habitats or other species. The invasive species involved in the present invention also include quarantine pests referred to by customs quarantine. Quarantine pests emphasize more on "economic importance", and the main consideration is that they have a significant impact on agricultural and forestry production and the environment. There is an overlapping relationship between the two. From a biological concept, because there are no administrative boundaries, based on the analysis of known natural distribution areas, species that are obviously far away from the invasion site are usually called invasive species in biology.

[0003] Invasive fish have impacted traditional fishing, aquaculture and major economic fish species naturally distributed in water bodies, and native fish population resources cannot be restored through natural cycles, resulting in immeasurable losses to the ecology and economy every year.

[0004] Therefore, how to suppress the population of invasive fish to improve the aquatic ecological environment is a technical problem that needs to be solved urgently. Summary of the invention

[0005] The present invention provides a method for improving the aquatic ecological environment by suppressing the population of invasive fish. By feeding the invasive fish as feed to native fish, the population of invasive fish can be gradually suppressed, thereby improving the impact of invasive fish on the local native species biodiversity and aquatic economy.

[0006] To achieve the above object, the present invention provides a method for improving the aquatic ecological environment by suppressing the population of invasive fish, comprising the following steps:

[0007] Determine whether invasive fish have an impact on the local native species biodiversity and aquatic economy. If so, select native fish that meet the specified conditions as the main body to inhibit invasive fish and promote fishery production and efficiency;

[0008] Continue to feed native fish with selected invasive fish as at least part of their diet;

[0009] The improvement effect of the aquatic ecological environment to be improved is determined based on the decline in the population of invasive fish.

[0010] In one embodiment, the determining whether the invasive fish has an impact on the local native species biodiversity and aquatic economy includes:

[0011] Determine whether the impact on local native species biodiversity and aquatic economy is caused by invasive fish;

[0012] If yes, determine the species of invasive fish and whether the invasive fish has a large population size;

[0013] If so, determine whether the current waters where the invasive fish exist are waters to be improved that need to be improved.

[0014] In one embodiment, in the selection of indigenous fish that meet specified conditions locally, the specified conditions include:

[0015] The indigenous fish are species native to the selected aquaculture water system;

[0016] The said indigenous fishes mainly feed on animals before being artificially bred and domesticated;

[0017] The artificial breeding technology of the indigenous fish is mature and can be domesticated by feeding commercial pellet feed;

[0018] The said indigenous fish species can be cultured in cages;

[0019] The market economic value of the indigenous fish is much higher than that of the omnivorous fish of the Cyprinidae family that have been farmed on a large scale, such as crucian carp, carp, grass carp, bream, etc.

[0020] In one embodiment, the step of continuously feeding the selected invasive fish as at least a portion of the feed to the native fish comprises:

[0021] According to different culture stages of the native fish, mixed feed containing invasive fish or all invasive fish feed is fed into the culture area of ​​the native fish.

[0022] In one embodiment, the mixed feed containing invasive fish is prepared by mixing the crushed material of the invasive fish obtained after crushing with the special feed of the native fish, wherein, when the mixed feed containing invasive fish is selected for feeding, as the breeding stage of the native fish increases, the proportion of the crushed material in the mixed feed increases successively, and the proportion of the special feed in the mixed feed decreases successively.

[0023] In one embodiment, when the all-invasive fish feed is selected for feeding, the feeding can be started when the native fish is cultured in the larval stage;

[0024] The whole invasive fish feed is a whole fish feed formed after dehydration, crushing, extrusion and ultra-low temperature freezing.

[0025] In one embodiment, the ultra-low temperature refrigeration temperature is -40--60°C, and the refrigeration time is at least 24 hours.

[0026] In one embodiment, the step of continuously using the selected invasive fish as at least a portion of feed to feed the native fish includes: selecting invasive fish that meet specified conditions as feed, wherein the specified conditions include:

[0027] The said exotic fish species were determined to be invasive fish species;

[0028] The diet of the invasive fish is mainly omnivorous or animal-oriented.

[0029] In one embodiment, the specified conditions also include: the self-protein content of the selected invasive fish is greater than 50%.

[0030] In one embodiment, the invasive fish include but are not limited to Perciformes, Cichlidae, etc.

[0031] Compared with the prior art, the present invention has one of the following advantages:

[0032] The present invention can gradually suppress the population of invasive fish by feeding native fish with invasive fish as feed, thereby improving the impact of invasive fish on the local native species biodiversity and aquatic economy. Since the suppression of invasive fish is proportional to the improvement of the aquatic ecological environment, as the population of invasive fish continues to decrease, the aquatic ecological environment will inevitably be improved;

[0033] By feeding invasive fish as feed to native fish, the breeding costs of native fish aquaculture can be reduced while suppressing the population of invasive species. The breeding scale can be adjusted according to the changes in the population of invasive fish, thus achieving the goal of reducing costs and increasing efficiency while suppressing the invasion.

[0034] Since invasive fish are used as feed to feed native fish, while a large number of invasive fish are obtained, native aquatic species will gradually recover their resources as the survival pressure is reduced. After the invasive fish population is reduced to a level that is insufficient to meet the feed demand, the aquaculture industry gradually moves away from invasive fish feed and enters traditional finished pellet feed farming, and restarts the cycle when the invasive fish spreads again. Since invasive fish cannot be completely eliminated from a biological level, due to the reduction in the cost of selecting native fish for farming, in the area where invasive fish are rampant, native fish with local advantages are selected for farming, which can gradually compress the living environment of invasive fish, so as to achieve the purpose of long-term suppression of invasive fish;

[0035] In waters where invasive fish are still farmed, the suppression method of the present invention can also be used to feed indigenous fish with invasive fish as feed to reduce the cost of indigenous fish farming, gradually reduce the scale of invasive fish farming, and use economic benefits as a breakthrough point until invasive fish farming is squeezed out of the waters, thereby suppressing the introduction of invasive fish and the risk of invasive fish spread from the source;

[0036] When the suppression method of the present invention is implemented, the purpose of invasion suppression is achieved by converting the aquaculture species, and the original aquaculture scale of the implementation water area is not increased, and there is no need to introduce new alien species. It has the characteristics of low environmental pressure and low risk. While continuing to utilize invasive species, the purchase, feeding and use of finished fish pellet feed outside the water area are greatly reduced, which can have a good effect on improving the water quality of the water area and reducing carbon emissions. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is a flow chart of the present invention. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0039] In the description of the present invention, it is necessary to understand that the terms "upper", "lower", "top surface", "bottom surface", "inside", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention. It should be noted that when a component is considered to be "connected" to another component, it may be directly connected to the other component or there may be a centrally arranged component at the same time. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0040] The present invention provides a method for improving an aquatic ecological environment by suppressing the population of invasive fish, comprising the following steps:

[0041] Determine whether invasive fish have an impact on the local native species biodiversity and aquatic economy. If so, select local fish that meet the specified conditions as indigenous fish to serve as the main body to suppress invasive fish and promote fishery production and efficiency;

[0042] Continue to feed native fish with selected invasive fish as at least part of their diet;

[0043] The improvement effect of the aquatic ecological environment to be improved is determined based on the decline in the population of invasive fish.

[0044] The present invention can gradually suppress the population of invasive fish by feeding native fish with invasive fish as feed, thereby improving the impact of invasive fish on the local native species biodiversity and aquatic economy. Since the amount of invasive fish suppressed is proportional to the effect of improving the aquatic ecological environment, as the population of invasive fish continues to decrease, the aquatic ecological environment will inevitably be improved.

[0045] Embodiment 1

[0046] like Figure 1 As shown, this embodiment provides a method for improving the aquatic ecological environment by suppressing the population of invasive fish, comprising the following steps:

[0047] S1. Determine whether invasive fish have an impact on the local native species biodiversity and aquatic economy. If so, select native fish that meet the specified conditions as the main body to inhibit invasive fish and promote fishery production and efficiency;

[0048] In this embodiment, in step S1, determining whether the invasive fish has an impact on the local native species biodiversity and aquatic economy includes:

[0049] Determine whether the impact on local native species biodiversity and aquatic economy is caused by invasive fish;

[0050] If yes, determine the species of invasive fish and whether the invasive fish has a large population size;

[0051] If so, determine whether the current waters where the invasive fish exist are waters to be improved that need to be improved.

[0052] Since the impact of invasive fish on the local native species biodiversity and aquatic economy is proportional to the invasive fish and the size of the invasive fish population, when it is determined that the current waters already contain a large population of invasive fish, it will inevitably have an impact on the native species biodiversity and aquatic economy in the current waters.

[0053] Optionally, invasive fish species in current waters include but are not limited to Perciformes and Cichlidae.

[0054] For example, the invasive fish in the current waters are Perciformes. Because this type of invasive fish has the characteristics of strong adaptability, strong reproductive capacity, high hatching survival rate, omnivorous and carnivorous, and few enemies, it will have an advantage in population size in the aquatic ecological environment it invades, and in the long-term competition it will squeeze the ecological niches and living space of other indigenous fish, thereby affecting the biodiversity of native species and the aquatic economy in the current waters.

[0055] Specifically, in step S1, local fish that meet specified conditions are selected as indigenous fish. The specified conditions include:

[0056] Condition a: The indigenous fish are native species in the selected aquaculture water system;

[0057] Condition b: Native fish feed mainly on animals before being artificially bred and domesticated;

[0058] Condition c: The artificial breeding technology of indigenous fish is mature and can be fed with commercial pellet feed for domestication;

[0059] Condition d: Indigenous fish can be cultured in cages;

[0060] Condition e: The market economic value of indigenous fish is much higher than that of the omnivorous carp fish that have been farmed on a large scale, such as crucian carp, carp, grass carp, bream, etc.

[0061] Through the above five conditions, it is possible to select the most suitable high-value native fish for farming, reduce the risk of reintroduction and spread of invasive fish, and select the most suitable local high-value native fish for farming invasive fish as feed.

[0062] Furthermore, the indigenous fish must meet the conditions for cage culture. Since the indigenous fish have the conditions for acclimatization with pellet feed, and at least part or all of the feed for culturing indigenous fish in the present invention is made of invasive fish, cage culture is conducive to centralized feeding of indigenous fish, and at the same time, it can also prevent the escape of artificially bred indigenous fish and cause genetic pollution to native species.

[0063] Furthermore, in waters to be improved that include invasive fish, or in locally selected aquaculture areas of native fish that do not include invasive fish, it is necessary to select areas in the waters that meet the requirements for aquaculture cages based on cage aquaculture conditions.

[0064] Exemplarily, the water body transparency in the water area is 200cm, the pH value is 7-8, the dissolved oxygen is above 6.8-7.0mg / L, and the water depth is more than 15m.

[0065] Furthermore, the length and width of the breeding cage are both 5 m, the depth is 3 m, and the diameter of the mesh is 1 cm.

[0066] Preferably, the aquaculture cages are aquaculture cages woven with polyethylene mesh wires, a sunshade net is arranged on the top of each aquaculture cage, and a bait-seeking platform is arranged on the bottom of each aquaculture cage.

[0067] S2. Continue to feed native fish with the selected invasive fish as at least part of their diet.

[0068] In this embodiment, according to different breeding stages of native fish, mixed feed containing invasive fish or feed for all invasive fish is fed into the breeding area of ​​native fish.

[0069] In one embodiment, specifically, when a mixed feed containing invasive fish is fed into a culture area of ​​native fish, the mixed feed is prepared by mixing crushed material of the invasive fish obtained after crushing with a special feed for the native fish.

[0070] For example, when the native fish is a long snout catfish, the special feed for the long snout catfish can be a special feed available on the market, wherein the type of the special feed is not limited here.

[0071] Furthermore, as the culture stage of the indigenous fish increases, the proportion of the crushed material in the mixed feed increases successively, and the proportion of the special feed in the mixed feed decreases successively.

[0072] For example, when the long-snout catfish is one winter old, the ratio of the crushed material to the special feed in the mixed feed is 1:4; when the long-snout catfish is two winters old, the ratio of the crushed material to the special feed in the mixed feed is 2:3.

[0073] In addition, in this embodiment, the mixed feed formed by mixing the crushed material of the invasive fish with the special feed for the native fish can be in the shape of round particles, strip particles, wet balls, etc.

[0074] Furthermore, the particle size of the mixed feed can be increased according to the different stages of the indigenous fish.

[0075] For example, when the long snout catfish is 1 winter old, a mixed feed of corresponding size can be selected for feeding according to the habits of the 1 winter old long snout catfish, and when the long snout catfish is 2 winter old, a mixed feed of corresponding size can be selected for feeding according to the habits of the 2 winter old long snout catfish. The requirements for the mixed feed to be fed are not limited here, and only need to meet the requirements suitable for fish growth.

[0076] In another embodiment, specifically, the feed introduced into the culture area of ​​the native fish is all-invasive fish feed.

[0077] Furthermore, the whole invasive fish feed is a whole fish feed that is formed into granules after being dehydrated, ultra-low temperature refrigerated, crushed and extruded.

[0078] Furthermore, first, the invasive fish are dehydrated to reduce their water content to approximately 30%; then, they are successively ultra-low temperature refrigerated, crushed and extruded to form granular feed suitable for different breeding stages.

[0079] Optionally, the invasive fish may be dehydrated by low-temperature freeze-drying or high-temperature drying.

[0080] Optionally, ultra-low temperature refrigeration is performed at a temperature of -40–-60°C for at least 24 hours.

[0081] Preferably, the ultra-low temperature refrigeration temperature is -40–-60°C and the refrigeration time is 48 hours.

[0082] Furthermore, the pellet feeding of the whole fish feed can be increased according to the different stages of the indigenous fish.

[0083] For example, when the native fish are at 1 winter age, the volume of the pelleted feed for all invasive fish after processing is approximately 0.3 cm 3 When the native fish are at the age of 2 winter, the volume of the pelleted feed for all invasive fish after processing is approximately 0.5 cm 3 .

[0084] In the above embodiments, pelleted feed for all invasive fish species can be prepared in a feed mill.

[0085] In addition, step S2 also includes: selecting invasive fish that meet specified conditions as feed, wherein the specified conditions include:

[0086] Condition a: Alien fish are judged as invasive fish;

[0087] Condition b: The diet of invasive fish is mainly predatory or omnivorous with a preference for animal feeding.

[0088] Furthermore, the above-mentioned conditions also include: the self-protein content of the selected invasive fish is greater than 50%.

[0089] This regulation enables invasive fish to meet their needs of converting it into feed, and feed it to native fish as feed according to their needs at different stages, providing them with necessary nutrition.

[0090] Preferably, the invasive fish selected as feed for native fish include but are not limited to Perciformes, Cichlidae, etc.

[0091] S3. Determine the effect of improving the aquatic ecological environment based on the decline in the population of invasive fish.

[0092] In one possible embodiment, the invasive fish are invasive fish originally existing in the waters to be improved, and the invasive fish in the waters to be improved are used as feed to feed native fish, thereby gradually suppressing the population of invasive fish in the waters to be improved, so as to improve the impact of invasive fish on the local native species biodiversity and aquatic economy.

[0093] Specifically, step S3 includes the following sub-steps:

[0094] S301, estimating the current total weight Mtotal of all invasive fish in the waters to be improved;

[0095] S302, after the native fish are cultured in cages in the culture area, the remaining total weight Mtotal of the invasive fish in the water area to be improved is estimated when the native fish reach the actual culture stage;

[0096] S303. Obtain the suppression amount of invasive fish in the water area to be improved according to the current total weight Mtotal of the invasive fish and the remaining total weight Mtotal of the invasive fish.

[0097] Specifically, step S301 includes the following sub-steps:

[0098] S3011. Use five-point sampling to obtain five unit areas of water in the water area to be improved, including:

[0099] The center point of the water surface of the water area to be improved is determined by the diagonal line of the water surface in the water area to be improved, and the center point is used as the sampling point;

[0100] Select four points on the diagonal line that are at the same distance from the sampling point as other sampling points;

[0101] Five unit water areas of equal volume are formed around the above five sampling points.

[0102] Among them, the above method is convenient for investigating the population changes of invasive fish.

[0103] S3012. Obtain the average weight of invasive fish per unit area of ​​water, including:

[0104] Count the total weight of invasive fish caught in five unit areas of water and obtain the average weight of invasive fish per unit area of ​​water

[0105] S3013. Estimate the current total weight Mtotal of invasive fish in the waters to be improved using the following formula, including:

[0106]

[0107] Among them, Mtotal is the estimated current total weight of invasive fish in the waters to be improved, m is the average weight of invasive fish per unit area of ​​water, Stotal is the total area of ​​waters to be improved, and Ssample plots is the number of waters per unit area.

[0108] Specifically, in step S302, when the indigenous fish put into the breeding area reaches the actual breeding stage, the same steps as in step S301 are used to estimate the remaining total weight Mtotal of the invasive fish in the water area to be improved when the indigenous fish are in the actual breeding stage.

[0109] Exemplarily, when the indigenous fish put into the breeding area reaches the first breeding stage, the same steps as in step S301 are used to estimate the remaining total weight Mtotal of the invasive fish in the waters to be improved when the indigenous fish are in the first breeding stage. When the indigenous fish put into the breeding area reaches the second breeding stage, the same steps as in step S301 are used to estimate the remaining total weight Mtotal of the invasive fish in the waters to be improved when the indigenous fish are in the second breeding stage.

[0110] Specifically, in step S303, the suppression amount of invasive fish in the water area to be improved is obtained according to the difference between the planned total weight Mtotal of the invasive fish and the remaining total weight Mtotal of the invasive fish.

[0111] Furthermore, the amount of inhibition of invasive fish by native fish when the native fish reaches the current breeding stage can be obtained according to the difference between the remaining total weights Mtotal of two consecutive invasive fish.

[0112] Exemplarily, the amount of inhibition of invasive fish by indigenous fish in the second breeding stage is obtained based on the difference between the remaining total weight Mtotal of invasive fish in the waters to be improved when the indigenous fish are in the first breeding stage and the remaining total weight Mtotal of invasive fish in the waters to be improved when the indigenous fish are in the second breeding stage.

[0113] In this embodiment, since the amount of invasive fish suppressed is proportional to the effect of improving the aquatic ecological environment, as the number of invasive fish in the waters to be improved continues to decrease, the aquatic ecological environment of the waters to be improved will inevitably be improved. By continuously using the above method, the living environment of invasive fish in the waters to be improved can be gradually compressed to achieve the purpose of long-term suppression of invasive fish.

[0114] Embodiment 2

[0115] This embodiment provides a method for improving the aquatic ecological environment by suppressing the population of invasive fish, comprising the following steps:

[0116] S1`, determine whether the invasive fish have an impact on the local native species biodiversity and aquatic economy. If so, select local fish that meet the specified conditions as indigenous fish.

[0117] S2`, continue to use the selected invasive fish as at least part of the feed for native fish.

[0118] S3`, determine the improvement effect of the aquatic ecological environment to be improved based on the decline in the population of invasive fish.

[0119] In this embodiment, the implementation steps of step S1' and step S2' are the same as the implementation steps of step S1 and step S2 in the above embodiment 1, and are not reviewed here.

[0120] The difference between this embodiment and the first embodiment lies in the specific implementation steps of step 3'. The implementation steps of step S3' are as follows:

[0121] In this embodiment, the amount of invasive fish suppressed is the total weight Ftotal of invasive fish converted into feed during the period from when native fish are introduced into the culture area to the specified actual culture stage.

[0122] Specifically, since the invasive fish need to be briefly dehydrated before being converted into feed to form dehydrated semi-wet granular fish paste, the total weight M dry weight of the invasive fish paste after dehydration is the same as the total weight F total of the invasive fish converted into feed, that is, F 总 =M 干重 .

[0123] Exemplarily, the dehydrated invading fish (i.e., the invading fish dry weight M 干重) are all converted into feed. The culture cycle of indigenous fish is i years. The average feed amount of the culture area in the i-th year is F i (F i The total feed mass F required for the cultivation of this batch of indigenous fish is 总 :

[0124]

[0125] That is, the sum of the average amount of feed fed in each year during the breeding cycle;

[0126] It is known that the formula for water content θ is:

[0127]

[0128] Among them, M 鲜重 is the weight of the invaded fish before dehydration;

[0129] The total weight of invasive fish consumed by a group of native fish in the aquaculture area (i.e., M 鲜重 ):

[0130]

[0131] Among them, since the suppression of invasive fish is proportional to the improvement of aquatic ecological environment, as the population of invasive fish in the waters to be improved continues to decrease, the aquatic ecological environment of the waters to be improved will inevitably improve. Continuously using the above method can gradually compress the living environment of invasive fish in the waters to be improved, so as to achieve the purpose of long-term suppression of invasive fish.

[0132] Application Example 1

[0133] In this application example, the breeding site of indigenous fish is the Daxicha section in the middle reaches of the Shuifeng Reservoir in Kuandian Manchu Autonomous County, Dandong City, Liaoning Province.

[0134] The Shuifeng Reservoir in Liaoning is a super-large artificial reservoir and the largest freshwater commercial fish breeding base in Asia. Over the years, the reservoir area has been affected by the large-scale escape and reproduction spread of invasive species such as river perch and zander. The resources of whitebait and smelt, which have relatively high economic benefits in the fishing industry, are almost exhausted. Other indigenous fish with economic value, such as crucian carp and carp, have found it difficult to form larval breeding seasons. The small non-economic fish at the bottom of the food chain, such as goby, bream, silver carp, and silver carp, and other environmentally oriented fish, are becoming increasingly scarce. The natural seedlings of high-level economic fish such as mandarin fish are hard to find. The fish invasion has already had a serious impact on the fishing industry, aquaculture industry, and aquatic ecological environment in the waters.

[0135] In this application example, based on the above situation, the local native and economically valuable longnose catfish is selected as the indigenous fish to suppress invasive fish, and naturally caught river perch and zander are selected as invasive fish for feed conversion, and the specific implementation steps in the above-mentioned embodiment 1 or embodiment 2 are adopted to carry out related breeding.

[0136] Among them, the number and specifications of farmed fish fry are as follows: Longnose catfish are one-winter-age farmed fish fry, with a total of 5,200 fry, and the weight of each farmed fish fry is 5-10g.

[0137] The total current weight M of perch and zander put into the total culture area is 250 kg.

[0138] In this application example, in the total breeding area, an open water area with a water transparency of 200 cm, pH 7-8, dissolved oxygen above 6.0 mg / L, and a water depth of more than 15 meters is selected as the native fish area, and each breeding cage is placed in the native fish area.

[0139] In this application example, 5 cages are used for breeding, and the 5 cages are arranged in a straight line. The length and width of each cage are 5m, the depth is 3m, and the diameter of the mesh is 1cm. The breeding cages are woven with polyethylene mesh wires, and a sunshade net is set on the top of each breeding cage, and a feeding platform is set at the bottom of each breeding cage.

[0140] The number of cultured fish fry put into each culture cage can be obtained according to the parameters of the above culture cages. For example, no more than 1040 cultured fish fry are put into each culture cage.

[0141] In this application example, mixed feed is used to feed the longnose catfish. When the longnose catfish is in the first stage, the mixed feed is fed once in the morning and once in the evening. In the mixed feed, the ratio of crushed perch and zander to additives is 1:5. When the longnose catfish is in the second and third stages, the ratio of crushed perch and zander to additives in the mixed feed also changes accordingly.

[0142] In this application example, after a 4-month feeding period, when the water temperature drops to 15 degrees Celsius, they basically stop foraging and prepare for wintering. The total weight of the feed conversion of river perch and zander is 125 kg. In early April 2023, they successfully overwintered and obtained more than 5,000 second-wintering longnose catfish with a single tail weight of about 100g. In April of the following year, the wintering was completed and the second breeding cycle began. During this process, the longnose catfish were kept in good health and had a high survival rate. There were no diseases and pests caused by feed, and no adverse reactions. Due to the use of river perch and zander for feed conversion, the cost of longnose catfish breeding feed has been reduced by at least about 25%. The reduction in this cost can also have a direct impact on the large-scale breeding and escaped and spread of the alien species channel catfish, reducing the risk of escape and invasion.

[0143] Application Example 2

[0144] In this application example, the breeding site of indigenous fish is Baishitang Reservoir in Longgang District, Shenzhen.

[0145] In this application example, the Baishitang Reservoir in Longgang District, Shenzhen is a small closed artificial reservoir with a total storage capacity of 1.2499 million cubic meters. It is a semi-aquaculture water body, and the original tilapia and largemouth sea bass in the reservoir are used as feed for invasive fish.

[0146] In this application example, the native and economically valuable Culter bream and Spinibarbus carchariflorus are selected as indigenous fish for suppressing invasive fish, and naturally caught tilapia and largemouth bass are selected as invasive fish for feed conversion, and the specific implementation steps in the above-mentioned embodiment 1 or embodiment 2 are adopted to carry out related breeding.

[0147] Among them, the number of cultured black carp is more than 500, and the length of each black carp is 15-20cm; the number of cultured spiny barb is more than 300, and the length of each spiny barb is 5-8cm.

[0148] Among them, the current total weight M of tilapia and largemouth bass invested in the total breeding area is 250 kg.

[0149] In this application example, in the total breeding area, an open water area with a water transparency of 100cm, pH 7-8, dissolved oxygen above 6.8-7mg / L, and a water depth of more than 5 meters is selected as the native fish area, and each breeding cage is placed in the native fish area.

[0150] In this application example, two breeding cages are used, each of which has a length and width of 15m, a depth of 3m, and a mesh diameter of 1cm. Each breeding cage is a breeding cage woven with polyethylene mesh wire, and a manual feeding platform is set on each breeding cage.

[0151] Among them, more than 500 Culter alba were put into one breeding cage, and more than 300 Spinibarbus karr were put into another breeding cage.

[0152] In this application example, mixed feed is used to feed Culter alba and Spinibarbus carchariformes. When Culter alba and Spinibarbus carchariformes are in the first stage, the mixed feed is fed once in the morning and evening. In the mixed feed, the ratio of crushed materials of tilapia and largemouth sea bass to additives is 1:5. When Culter alba and Spinibarbus carchariformes are in the second and third stages, the ratio of crushed materials of tilapia and largemouth sea bass to additives in the mixed feed also changes accordingly.

[0153] In this application example, after a feeding period of 280 days from March to October, the total weight of feed conversion using tilapia and largemouth bass was more than 240 kilograms, and a total of 461 Culter albus with a single tail weight of about 500g were obtained, and a total of 274 Spinellipis californicus with a single tail weight of about 500g were obtained. The Culter albus and Spinellipis californicus were raised in good health, with a high survival rate, and no diseases and insect pests caused by feed, and no adverse reactions. Due to the use of tilapia and largemouth bass for feed conversion, the cost of breeding feed for Culter albus and Spinellipis californicus was reduced by at least about 30%.

[0154] The method provided by the present invention can gradually solve the impact of local invasive fish on local indigenous fish farming, and while improving the aquatic ecological environment, it can also lay a good foundation for the subsequent continued fishing of traditional economic fish.

[0155] The method provided by the present invention can improve the economic benefits obtained by fishery farmers from breeding local native high-value fish while effectively utilizing the resources of invasive fish to reduce breeding costs.

[0156] In the method provided by the present invention, since the protein content of the invasive fish itself is greater than 50%, the crushed material of the invasive fish can be used as a part of the breeding feed to replace the fish meal in the existing feed. It can not only serve as a source of protein and amino acids to provide sufficient nutrients for the native fish, but also realize the feed conversion of the invasive fish, thereby reducing the breeding cost.

[0157] The method provided by the present invention can effectively suppress the overall population of invasive fish that have already invaded natural water bodies and are still spreading, mainly solving the problem of the number of invasive fish populations in freshwater waters. By making full use of the overall classification composition and biological characteristics of fish that have already invaded my country, combined with the mutually beneficial integration of fishing, aquaculture and the ecological environment, a complete, sustainable and closed-loop long-term inhibition cycle method is constructed, which can effectively suppress invasive fish species such as Perciformes that have a wide distribution range and huge population. It has the characteristics of low investment cost, wide application range, quick effect, environmental friendliness (can repair the original ecological environment), strong sustainability, significant environmental benefits and economic benefits, and has the potential for large-scale promotion and application.

[0158] The method provided by the present invention is mainly applicable to aquatic ecological environments mainly in reservoir aquaculture and natural water bodies dominated by productive fishery fishing activities.

[0159] The invasive fish species that can be inhibited by the method provided by the present invention include but are not limited to Perciformes, Cichlidae, etc.

[0160] The method provided by the present invention is based on the invasion status of invasive freshwater fish species in the country, the classification and composition structure of invasive freshwater fish, and the diffusion distribution area, combined with the feeding habits and regional advantages of aquatic species and the application needs of freshwater fish breeding feed. Because my country's invasive freshwater fish are generally systematically classified as Perciformes fish, most of them are fully predatory or omnivorous and carnivorous, their own nutritional value and protein content fully meet the needs of various types of aquatic products and even extend to the raw material needs of animal husbandry breeding feed.

[0161] The present invention provides a complete closed-loop method for sustainably inhibiting the spread of invasive species. While minimizing the pressure on the aquatic ecological environment, it can continuously improve the living environment of native aquatic organisms, and take into account the increase in production and efficiency of the fishing industry and fishery production, and can even partially alleviate my country's dependence on imported feed raw materials.

[0162] The above description is only a preferred embodiment of the present invention, which is only illustrative and not restrictive of the present invention. Those skilled in the art understand that many changes, modifications, and even equivalences may be made to the present invention within the spirit and scope defined by the claims of the present invention, but all of them will fall within the scope of protection of the present invention.

Claims

1. A method for improving aquatic ecological environment by suppressing the population of invasive fish, characterized in that: The following steps are involved: Determine whether invasive fish have an impact on the local native species biodiversity and aquatic economy. If so, select native fish that meet the specified conditions as the main body to inhibit invasive fish and promote fishery production and efficiency; Continue to feed native fish with selected invasive fish as at least part of their diet; The improvement effect of the aquatic ecological environment to be improved is determined based on the decline in the population of invasive fish.

2. The method for improving the aquatic ecological environment by suppressing the population of invasive fish according to claim 1, characterized in that: In determining whether invasive fish have an impact on the local native species biodiversity and aquatic economy, the following are included: Determine whether the impact on local native species biodiversity and aquatic economy is caused by invasive fish; If yes, determine the species of invasive fish and whether the invasive fish has a large population size; If so, determine whether the current waters where the invasive fish exist are waters to be improved that need to be improved.

3. The method for improving the aquatic ecological environment by suppressing the population of invasive fish according to claim 1, characterized in that: In the above-mentioned selection of indigenous fishes that meet the specified conditions, the above-mentioned specified conditions include: The indigenous fish are species native to the selected aquaculture water system; The said indigenous fishes mainly feed on animals before being artificially bred and domesticated; The artificial breeding technology of the indigenous fish is mature and can be domesticated by feeding commercial pellet feed; The said indigenous fish species may be cultured in cages; The market economic value of the indigenous fish is much higher than that of the omnivorous carp fish that have been farmed on a large scale.

4. The method for improving the aquatic ecological environment by suppressing the population of invasive fish according to claim 1, characterized in that: In the method of continuously feeding the selected invasive fish as at least a portion of the feed to the native fish, the method comprises: According to different culture stages of the native fish, mixed feed containing invasive fish or all invasive fish feed is fed into the culture area of ​​the native fish.

5. The method for improving the aquatic ecological environment by suppressing the population of invasive fish according to claim 4, characterized in that: The mixed feed containing invasive fish is prepared by mixing the crushed material of the invasive fish obtained after crushing with the special feed of the native fish. When the mixed feed containing invasive fish is selected for feeding, as the breeding stage of the native fish increases, the proportion of the crushed material in the mixed feed increases successively, and the proportion of the special feed in the mixed feed decreases successively.

6. The method for improving the aquatic ecological environment by suppressing the population of invasive fish according to claim 4, characterized in that: When the all-invasive fish feed is chosen to be fed, the feeding can be started when the larval stage of the native fish is cultivated; The whole invasive fish feed is a whole fish feed formed after dehydration, crushing, extrusion and ultra-low temperature freezing.

7. The method for improving the aquatic ecological environment by suppressing the population of invasive fish according to claim 6, characterized in that: The ultra-low temperature refrigeration is -40--60°C and the refrigeration time is at least 24 hours.

8. The method for improving the aquatic ecological environment by suppressing the population of invasive fish according to claim 4, characterized in that: The method of continuously using the selected invasive fish as at least a part of feed to feed the native fish includes: selecting invasive fish that meet specified conditions as feed, wherein the specified conditions include: Exotic fish are judged to be invasive; The diet of the invasive fish is mainly omnivorous or animal-oriented.

9. The method for improving the aquatic ecological environment by suppressing the population of invasive fish according to claim 8, characterized in that: The specified conditions also include: the self-protein content of the selected invasive fish is greater than 50%.

10. The method for improving the aquatic ecological environment by suppressing the population of invasive fish according to any one of claims 1 to 9, characterized in that: The invasive fish include but are not limited to Perciformes and Cichlidae.

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