Polyculture method of macroalgae and siganus siganus

Abstract

The invention discloses a polyculture method of macroalgae and siganus siganus. By changing a single culture mode, space resources of the whole water body are utilized to the maximum extent, and the water body utilization rate is increased. The macroalgae are bred in the middle-upper water area of the pond through the net cage, sufficient sunlight in the middle-upper water area is fully utilized for growth of the macroalgae, the space under the net cage serves as a place for fish to hide and inhabit, a comfortable environment is provided for fish breeding, fish stress is reduced, and diseases are reduced. And the macroalgae and the cultured fishes are cultured in an isolated manner through the netting, so that the amount of algae ingestion of the fishes can be controlled, healthy growth of the macroalgae is ensured, and collection of the macroalgae is facilitated. The differentiation of the ecological niche enables the fishes and the algae to be mutually beneficial and coexist in the same water body.

Description

Technical Field

[0001] The invention relates to the technical field of aquaculture, and in particular to a method for polyculturing large seaweed and blue fish. Background Art

[0002] Large seaweed is not only a kind of marine vegetable rich in various vitamins and trace elements, but also a health food containing various physiologically active substances. It has significant therapeutic effects in lowering blood sugar, lowering blood lipids, and anti-tumor, and has become the main raw material for the preparation of marine drugs; chemical products such as algin and mannitol can be extracted from kelp, Gracilaria, and Eucheuma, which are the main raw materials of the algae chemical industry. Many large seaweeds grow rapidly and absorb nutrients quickly. They are widely used in marine ecological restoration and water quality improvement projects. They are often used as biological filters to purify the water quality of breeding ponds and reduce the concentration of nitrogen and phosphorus in water bodies. In recent years, the production of seaweed green manure and anti-adverse growth hormone has become an emerging industry for seaweed processing and utilization. Therefore, the consumer market for seaweed is very broad, whether it is edible, medicinal, or as an industrial and agricultural raw material, it is of great development value.

[0003] Bluefish (Acanthopagrus schlegelii) is a general term for fish of the family Acanthopagrus and genus Acanthopagrus. It is widely distributed along the coast of the western Pacific Ocean. It is an omnivorous fish that mainly feeds on plants, but after artificial domestication, it can also eat compound feed. Bluefish has the characteristics of tender meat, delicious taste and rich nutrition, and is very popular in the market. It grows quickly, has few diseases, and has strong adaptability. It is a high-quality fish species suitable for artificial breeding.

[0004] With the rapid development of aquaculture technology, the traditional single-species farming model faces various problems. For example, the farming model of a single fish easily leads to over-intensive farming of a large number of the same species, resulting in the accumulation of waste and excrement in the water. These wastes include undigested feed, metabolites and feces, which will increase the concentration of nutrients such as ammonia nitrogen, nitrite and phosphorus in the water, leading to water quality deterioration and eutrophication. In addition, farming usually requires a large amount of feed, energy and water resources, which will lead to waste of resources and increased costs. The cultivation of a single algae will cause a waste of space in the lower layer of the pond with weak light, and a large amount of nutrients will be consumed during the growth of algae. The nutrients in the seawater cannot meet the growth of algae, so it is necessary to regularly add nutrients for algae growth. These shortcomings not only affect the economic benefits and farming efficiency, but may also have a negative impact on the environment and ecosystem. Summary of the invention

[0005] The object of the present invention is to overcome at least one disadvantage of the prior art and provide a method for polyculturing large seaweed and blue fish.

[0006] The technical solution adopted by the present invention is:

[0007] The present invention provides a method for polyculturing large seaweed and blue fish, comprising the following steps:

[0008] 1) Set up the breeding environment: Set up a breeding pond with a water depth of 1.2 to 1.5 meters, hang a breeding net in the middle of the breeding pond, and fix the breeding cages that are 1 / 4 to 1 / 3 of the area of ​​the breeding pond. The depth of the bottom of the cage from the water surface cannot exceed 1 meter, and the upper side of the cage is 20 to 30 cm above the water surface.

[0009] 2) Cultivation of large seaweed and stocking of fish: Large seaweed is placed in the aquaculture cages. After 1 to 2 weeks of large seaweed cultivation, blue fish are stocked for aquaculture;

[0010] 3) Seaweed harvesting and fish catch: Check the growth of seaweed every day, remove some seaweed from the upper layer of the culture cage to prevent it from blocking the sunlight, and catch bluefin mullets weighing more than 100g at the right time.

[0011] In some examples, the bottom of the culture cage is 0.5 to 0.8 m away from the bottom of the culture pond.

[0012] In some examples, the culture density of the macroalgae is 0.5-1 kg per square meter.

[0013] In some examples, the macroalgae in step 2) is selected from Pteris racemosus or Botrytis cinerea.

[0014] In some examples, the stocking density of blue fish in step 2) is 40 to 60 per cubic meter of water.

[0015] In some examples, the stocking specifications of the blue fish in step 2) are 1.5-3 g / tail in weight and 3-5 cm / tail in length.

[0016] In some examples, the feed feeding amount is: the daily feed feeding amount cannot be higher than 3% of the total weight of the blue fish.

[0017] In some examples, the dissolved oxygen in the culture pond is greater than 5 mg / L, the water temperature is 22-31°C, the salinity is 29-32‰, the pH is 7.9-8.3, the dissolved oxygen is greater than 5 mg / L, and the ammonia nitrogen is less than 0.3 mg / L.

[0018] The beneficial effects of the present invention are:

[0019] 1. Changing the single breeding mode, maximizing the use of the space resources of the entire water body, and improving the utilization rate of the water body. Large seaweed is raised in the middle and upper waters of the pond through cages, making full use of the abundant sunlight in the middle and upper waters for its growth, and the space under the cages becomes a place for fish to hide and live, providing a comfortable environment for farmed fish, reducing fish stress and reducing the occurrence of diseases. And the large seaweed is isolated from the farmed fish through the net, which can not only control the amount of algae eaten by fish, ensure the healthy growth of large algae, but also facilitate the collection of large algae. The differentiation of ecological niches enables fish and algae to coexist mutually beneficially in the same water body.

[0020] 2. Fish release carbon dioxide and excrete organic metabolites such as nitrogen and phosphorus during their growth, polluting the water body. The surface of the large algae in the cage is adsorbed with a large number of nitrifying bacteria, protozoa and other small organisms that feed on organic debris. These organisms decompose the metabolic organic matter produced by fish into inorganic salts or tiny organic matter. Large algae absorb a large amount of carbon dioxide, inorganic salts, etc. during their growth, which not only purifies the water quality and reduces the frequency and amount of water changes, but also the large seaweed can be used as high-quality bait for fish, reducing feed input, improving bait utilization efficiency, greatly reducing breeding costs, and increasing economic benefits. It is an economical and effective carbon sink fishery model.

[0021] 3. Through mixed breeding, a large amount of large seaweed can be obtained. Large seaweed is a natural food with rich nutrition and multiple functions. It contains rich polysaccharides, starch, protein, vitamins, minerals and various biologically active substances. It has the functions of enhancing immunity, improving the intestine, anti-oxidation, lowering blood pressure, etc. It can be used as a high-quality food for humans. Feeding fish with it can reduce the occurrence of farmed fish diseases, promote fish growth, shorten the breeding cycle, and the fish that eat large seaweed have a better taste.

[0022] 4. As a mixed culture object, blue fish has the following advantages: blue fish grows rapidly, has a short breeding cycle, and can quickly reach market specifications; blue fish has delicious meat and high economic value; blue fish has strong adaptability to the water environment, strong disease resistance, and is easy to breed. DETAILED DESCRIPTION

[0023] The following disclosure provides many different embodiments or examples for implementing different solutions of the present invention.

[0024] Example 1

[0025] The present embodiment provides a method for co-culturing Brackenia racemosus and Yellow-spotted Bluefish, comprising: selecting and preparing a culture pond, cultivating large seaweeds, selecting and placing fish species, and daily management.

[0026] (1) Selection and preparation of breeding ponds

[0027] The breeding pond is square, 6m long, 5m wide, 1.6m deep, and has a bottom area of ​​30m 2 The pond is covered with a light-transmitting roof to ensure that there is sufficient sunlight on the pond. The breeding pond is cleaned and disinfected, and sand-filtered seawater is injected into the pond to a depth of 1.4m. Air stones are arranged around the pond and sunk to the bottom of the pond. The air stones are spaced 1.5 meters apart. A square nylon breeding net is hung in the middle of the pond by ropes or stainless steel pipes to form a breeding cage. The length, width and height of the net are 4m×2.5m×1m, the mesh size is 1cm, and the bottom area is 10m 2 , the bottom of the cage is 0.6m away from the bottom of the pool, and the depth of the bottom of the cage from the water surface cannot exceed 1m, ensuring sufficient sunlight to enter the bottom of the net. The upper side of the cage is 20cm above the water surface to prevent the fish in the breeding pond from jumping into the cage to eat and destroy the seaweed in the cage. Five air stones are evenly arranged in the cage. After the cage is arranged, 4 PVC pipes with a diameter of 2cm are spliced ​​with 90° elbows to make a square frame with the same size as the opening of the net. The PVC pipe square frame is punched with several round holes with a diameter of 0.3cm. The purpose of punching holes is that when the PVC pipe square frame is put into the water, seawater enters the PVC pipe through the round holes, so that the PVC pipe square frame can sink to the bottom of the water.

[0028] (2) Cultivation of large seaweed

[0029] After the cages are arranged, select healthy, strong, disease-free, and intact racemose algae seedlings, use ropes to fix the algae around the square frame, place the racemose algae at a density of 1kg per square meter of the cage area, and sink the square frame tied with algae into the cage. The square frame can not only fix the seaweed, but also press the bottom of the net into the water through gravity, so that the net is fixed and not twisted. The water in the breeding pond is adjusted to micro-flow water, and the amount of gas stone is adjusted to make the dissolved oxygen content of the breeding water ≥5mg / L. After growing seaweed, after 1 week of cultivation, the seaweed grows well and the water quality is stable, and blue fish can be released.

[0030] (3) Selection and release of fish species

[0031] Reasonable selection of fish species can ensure ecological balance during the breeding process and improve breeding efficiency. Choose yellow-spotted blue fish with uniform size, smooth body surface, normal body color, strong vitality and no injuries. The stocking specification is an average weight of 1.73g / tail, an average body length of 4.21cm, and a stocking density of 40 per square meter of water. Before the fry are released, the smaller fish are picked out to prevent the small fish from entering the cage to eat large seaweed. A total of 1,200 blue fish are released.

[0032] (4) Daily management

[0033] ① Feeding management: No feed is given during the first two days after the fry are released. The activity of the blue fish fry is observed. After two days, a small amount of feed is fed. After the water quality stabilizes, the feed amount is appropriately increased according to the feeding situation of the fry. However, the daily feed amount cannot exceed 3% of the total weight of the fish. After three weeks of seaweed cultivation, the seaweed in the cage increases exponentially, and some seaweed will grow through the mesh for the blue fish to eat. At this time, check the growth of seaweed every day and remove some seaweed from the upper layer of the cage to prevent too much seaweed from blocking the sunlight and hindering the growth of seaweed in the middle and lower layers. The removed seaweed is sold in the market or placed outside the cage for the blue fish to eat. The feeding strategy for the day can be formulated according to the amount of seaweed removed. When there is a lot of seaweed for the blue fish, feed can be fed in small amounts or stopped.

[0034] ② Water quality monitoring: Keep the water clean and transparent, regularly test water quality parameters, and ensure that the water temperature is controlled between 22-31℃, salinity is 29-32‰, pH is 7.9-8.3, dissolved oxygen is greater than 5mg / L, and ammonia nitrogen is less than 0.3mg / L during the breeding process. Inspect the breeding pond every day, observe the growth status of blue fish and racemose algae, discover diseases and abnormal conditions in time, and take corresponding emergency measures. When there is a lot of residual bait and excrement accumulated at the bottom of the breeding pond, it is necessary to suck out the sewage in time. After the suction is completed, the water intake should be increased to replenish the pool water back to the original water level as soon as possible to prevent the algae in the cage from emerging from the water and causing death.

[0035] After 4 months of breeding, the experimental fish reached the market size. At this time, the pond was cleaned and a total of 239.4 kg of blue fish were obtained.

[0036] Example 2

[0037] The present embodiment provides a method for co-culturing sea grapes and blue fish, which includes: selecting and preparing a culture pond, cultivating large seaweeds, selecting and placing fish species, and daily management.

[0038] (1) Selection and preparation of breeding ponds

[0039] The breeding pond is square, 6m long, 5m wide, 1.6m deep, and has a bottom area of ​​30m 2 The pond is covered with a light-transmitting roof to ensure that there is sufficient sunlight on the pond. The breeding pond is cleaned and disinfected, and sand-filtered seawater is injected into the pond to a depth of 1.4m. Air stones are arranged around the pond and sunk to the bottom of the pond. The air stones are spaced 1.5 meters apart. A square nylon breeding net is hung in the middle of the pond by ropes or stainless steel pipes to form a breeding cage. The mesh size of the net is 1cm, and the length, width and height are 4m×2.5m×1m respectively, with a bottom area of ​​10m 2, the bottom of the cage is 0.6m away from the bottom of the pool, and the depth of the bottom of the cage from the water surface cannot exceed 1m, ensuring sufficient sunlight to the bottom of the cage, and the upper side of the cage is 20cm above the water surface to prevent the fish in the breeding pond from jumping into the cage, and 5 air stones are evenly arranged in the cage. After the cage is arranged, 4 PVC pipes with a diameter of 2cm are spliced ​​with 90° elbows to make a square frame with the same size as the opening of the net. The PVC pipe square frame is punched with several round holes with a diameter of 0.3cm. The purpose of punching holes is that when the PVC pipe square frame is put into the water, seawater enters the PVC pipe through the round holes, so that the PVC pipe square frame can sink to the bottom of the water.

[0040] (2) Cultivation of large seaweed

[0041] After the cages are arranged, choose healthy, strong, disease-free, and intact sea grape seedlings, use ropes to fix large algae around the square frame, place sea grapes at a density of 1kg per square meter of the cage area, and sink the square frame tied with algae into the net. The square frame can not only fix the seaweed, but also press the bottom of the cage into the water through gravity, so that the cage is fixed and not twisted. The water in the breeding pond is adjusted to micro-flow water, and the amount of gas stone is adjusted to make the dissolved oxygen content of the breeding water ≥5mg / L. After growing seaweed, after 1 week of cultivation, the seaweed grows well and the water quality is stable, and blue fish can be released.

[0042] (3) Selection and release of fish species

[0043] Reasonable selection of fish species can ensure ecological balance during the breeding process and improve breeding efficiency. Choose blue fish with uniform size, smooth body surface, normal body color, strong vitality and no injuries. The stocking specifications are 1.73g / tail with an average body weight of 4.21cm and a stocking density of 40 per square meter of water. Before the fry are released, the smaller fish are picked out to prevent them from entering the cage to eat large seaweed.

[0044] (4) Daily management

[0045] ① Feeding management: No feed is given during the first two days after the fry are released. The activity of the blue fish fry is observed. After two days, a small amount of feed is fed. After the water quality stabilizes, the amount of feed is appropriately increased according to the feeding situation of the fry. However, the daily feed amount cannot exceed 3% of the total weight of the fish. After three weeks of sea grape cultivation, the sea grapes in the cage will grow exponentially. Some sea grapes will grow through the mesh for the blue fish to eat. At this time, check the growth of sea grapes every day and remove some sea grapes from the upper layer of the cage to prevent too many sea grapes from blocking the sunlight and hindering the growth of sea grapes in the middle and lower layers. The removed sea grapes can be sold to the market or put outside the net for the blue fish to eat. The feeding strategy for the day can be formulated according to the amount of algae removed. When there are too many sea grapes for the blue fish, feed can be fed in small amounts or stopped.

[0046] ② Water quality monitoring: Keep the water clean and transparent, regularly test water quality parameters, and ensure that the water temperature is controlled between 22-31℃, salinity is 29-32‰, pH is 7.9-8.3, dissolved oxygen is greater than 5mg / L, and ammonia nitrogen is less than 0.3mg / L during the breeding process. Inspect the breeding pond every day, observe the growth status of blue fish and sea grapes, discover diseases and abnormal conditions in time, and take corresponding emergency measures. When there is a lot of residual bait and excrement accumulated at the bottom of the breeding pond, it is necessary to suck out the sewage in time. After the suction is completed, the water intake should be increased to replenish the pool water to the original water level as soon as possible to prevent the algae in the cage from emerging from the water and causing death.

[0047] After 4 months of breeding, the experimental fish reached the market specifications, and the pond was cleaned to obtain a total of 264.6 kg of blue fish.

[0048] Comparative Example 1

[0049] The present embodiment provides a method for raising bluefin bream alone, comprising: selecting and preparing a breeding pond, selecting and placing fish species, and daily management.

[0050] (1) Selection and preparation of breeding ponds

[0051] The breeding pond is square, 6m long, 5m wide, 1.6m deep, and has a bottom area of ​​30m 2 The pond is covered with a light-transmitting roof to ensure that there is sufficient sunlight to illuminate the pond. The breeding pond is cleaned and disinfected, and sand-filtered seawater is injected into the pond to a depth of 1.4m. Air stones are arranged around the pond, and the air stones sink to the bottom of the pond with an interval of 1.5 meters.

[0052] (2) Selection and release of fish species

[0053] Reasonable selection of fish species can ensure ecological balance during the breeding process and improve breeding efficiency. Choose blue fish with uniform size, smooth body surface, normal body color, strong vitality and no injuries. The stocking specifications are an average weight of 1.73g / tail, an average body length of 4.21cm, and a stocking density of 40 fish per square meter of water.

[0054] (3) Daily management

[0055] ① Feeding management: Do not feed the fry during the first 2 days after they are released. Observe the activity of the blue fish fry more. After 2 days, start feeding a small amount of feed. After the water quality stabilizes, increase the amount of feed appropriately based on the feeding situation of the fry. However, the daily feed amount cannot exceed 3% of the total weight of the fish.

[0056] ② Water quality monitoring: Keep the water clean and transparent, regularly test water quality parameters, and ensure that the water temperature is controlled between 22-31℃, salinity is 29-32‰, pH is 7.9-8.3, dissolved oxygen is greater than 5mg / L, and ammonia nitrogen is less than 0.3mg / L during the breeding process. Inspect the breeding pond every day, observe the growth status of the blue fish, discover diseases and abnormal conditions in time, and take corresponding emergency measures. When there is a lot of residual bait and excrement accumulated at the bottom of the breeding pond, it is necessary to suck the sewage in time, and replenish the pool water to the original water level after the suction is completed.

[0057] After 4 months of breeding, the experiment reached the market specifications, the pond was cleaned and a total of 191.6kg of blue fish was obtained.

[0058] The results of each embodiment and comparative example are shown in Table 1. It can be seen that the mixed culture of sea grapes and blue fish and the mixed culture of racemose ferns and blue fish have obvious advantages over the single culture of blue fish in terms of daily weight gain rate, feed coefficient, water quality and output. According to the cost of 10 yuan per kilogram of feed and 0.5 yuan of electricity per cubic water, the production of each ton of blue fish saves 6915 yuan and 5790 yuan respectively in the mixed culture of sea grapes and blue fish and the mixed culture of racemose ferns and blue fish compared with the single culture of blue fish. In addition, in this breeding experiment, the mixed culture of sea grapes and blue fish and the mixed culture of racemose ferns and blue fish produced 357kg of racemose ferns and 443kg of sea grapes, respectively. The growth of seaweed not only purifies the water quality, but the produced seaweed can also be used as bait to directly feed blue fish, and the seaweed can be sold as raw materials for food and health products, etc., which improves the economic benefits of breeding.

[0059] Table 1 Comparison of polyculture and monoculture effects

[0060]

[0061]

[0062] The above is a further detailed description of the present invention, which should not be regarded as a limitation on the specific implementation of the present invention. For ordinary technicians in the technical field to which the present invention belongs, simple deduction or replacement without departing from the concept of the present invention is within the protection scope of the present invention.

Claims

1. A method for polyculturing large seaweed and blue fish, characterized in that: The following steps are involved: 1) Set up the breeding environment: Set up a breeding pond with a water depth of 1.2 to 1.5 meters, hang a breeding net in the middle of the breeding pond, and fix the breeding cages that are 1 / 4 to 1 / 3 of the area of ​​the breeding pond. The depth of the bottom of the cage from the water surface cannot exceed 1 meter, and the upper side of the cage is 20 to 30 cm above the water surface. 2) Cultivation of large seaweed and stocking of fish: Large seaweed is placed in the aquaculture cages. After 1 to 2 weeks of large seaweed cultivation, blue fish are stocked for aquaculture; 3) Seaweed harvesting and fish catch: Check the growth of seaweed every day, remove some seaweed from the upper layer of the culture cage to prevent it from blocking the sunlight, and catch bluefin mullets weighing more than 100g at the right time.

2. The polyculture method according to claim 1, characterized in that The bottom of the breeding cage is 0.5 to 0.8 m away from the bottom of the breeding pond.

3. The polyculture method according to claim 1, characterized in that The cultivation density of the large seaweed is 0.5-1 kg per square meter.

4. The polyculture method according to claim 1, characterized in that In the step 2), the large seaweed is selected from Pteris racemosus or Botrytis cinerea.

5. The polyculture method according to claim 1, characterized in that In the step 2), the stocking density of blue fish is 40 to 60 per cubic meter of water.

6. The polyculture method according to claim 1, characterized in that In the step 2), the stocking specifications of the blue fish are 1.5-3 g / tail in weight and 3-5 cm in length / tail.

7. The polyculture method according to claim 1, characterized in that The feed feeding amount is: the daily feed feeding amount cannot be higher than 3% of the total weight of the blue fish.

8. The polyculture method according to claim 1, characterized in that The dissolved oxygen in the breeding pond is greater than 5 mg / L, the water temperature is 22-31°C, the salinity is 29-32‰, the pH is 7.9-8.3, the dissolved oxygen is greater than 5 mg / L, and the ammonia nitrogen is less than 0.3 mg / L.

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