Water quality ecological regulation and control method for multi-nutrition-level fish, shrimp and shellfish polyculture seawater pond

Abstract

The invention relates to a water quality ecological regulation and control method for a multi-nutritional-level fish, shrimp and shellfish polyculture seawater pond, and the method belongs to the technical field of pond culture. According to the method, the overall performance of a system is improved by reasonably matching the fish, shrimp and shellfish polyculture specification and density and cooperatively using a carbon source (maintaining the C / N ratio of 10-15: 1) bacillus; a four-dimensional ecological circulation system of fish excretion, shrimp disturbance, shellfish purification and microbial degradation is constructed, perfect ecological balance of the culture system is achieved, no pollutant is discharged in the culture process, and water change can be avoided.

Description

Technical Field

[0001] The invention belongs to the technical field of pond aquaculture, and in particular relates to a water quality ecological control method for a multi-nutrient-level fish, shrimp and shellfish polyculture seawater pond. Background Art

[0002] Seawater pond aquaculture is an important pillar of aquaculture in my country, but long-term high-density aquaculture and monoculture have led to problems such as bottom degradation, deterioration of water quality, frequent diseases and tailwater pollution, which seriously restrict the sustainable development of the industry. There are existing technologies to improve this technical problem by adjusting the aquaculture model, such as by building an ecological circulation system, such as fish-shellfish-algae integrated aquaculture, so that fish feces and leftover bait provide nutrition for algae, and algae photosynthesis produces oxygen for shellfish and fish to breathe, realizing material recycling and reducing pollution. Or, based on the feeding habits and living habits of different aquaculture organisms, mixed aquaculture can be carried out, such as mixed aquaculture of shrimp and filter-feeding shellfish. The leftover shrimp bait and feces are decomposed by microorganisms and then ingested by shellfish, reducing water pollution. However, the selection of mixed aquaculture varieties and the matching ratio is a technical problem. It is difficult to match the mixed system to a perfect ecological balance and achieve almost no pollutant discharge. Summary of the Invention

[0003] The present invention aims to provide a method for ecologically regulating water quality in seawater ponds for the polyculture of fish, shrimp, and shellfish at multiple trophic levels. The method improves the overall performance of the system by studying the specifications and densities of the mixed culture of fish, shrimp, and shellfish, and using Bacillus as a carbon source (maintaining a C / N ratio of 10-15:1). This system constructs a four-dimensional ecological cycle system of "fish excretion - shrimp disturbance - shellfish purification - microbial degradation," achieving a perfect ecological balance in the aquaculture system. No pollutants are discharged during the aquaculture process, and zero water changes are required.

[0004] To achieve the above purpose, the present invention adopts the following technical solutions:

[0005] A method for ecologically regulating water quality in a multi-trophic-level seawater pond for polyculture of fish, shrimp, and shellfish, the method being specifically as follows:

[0006] Step 1: After cleaning the pond, add seawater to the pond and cultivate the water;

[0007] Step 2: On the first day, first release Japanese shrimp, with a size of 1-1.5 cm and a stocking density of 44,000-46,000 shrimp / mu;

[0008] On the second day, add Manila clams and select healthy, undamaged, uniform-sized clams with fresh colors. The size is 135 clams per kilogram, and 70,000 to 75,000 clams per mu.

[0009] On the fourth day, add healthy chrysanthemum yellow pufferfish of uniform size, 6-7 cm in length, at a stocking density of 1,000-1,200 per mu.

[0010] Step 3, (1) Breeding and management: Feed the pufferfish with a complete feed 1-3 times a day; the daily feed amount is 3%-20% of the fish body weight, depending on the water temperature and the size of the fish;

[0011] Shrimp bait: Feed the shrimp with biological bait and compound feed in the pond 2-4 times a day in the early stage, with the amount fed in the morning and evening accounting for 60% of the normal breeding feeding amount;

[0012] There is no need to feed artificial feed to Manila clams;

[0013] (2) Carbon source and Bacillus spores feeding standards: From the start of cultivation to the 40th day, carbon source and Bacillus spores are fed every 15-20 days, every 10-15 days from the 41st to the 80th day, and every 7-10 days from the 81st to the 120th day. The dosage is 300-400 g of carbon source per mu and 100-150 g of Bacillus spores per mu.

[0014] (3) No water changes during the entire breeding period.

[0015] The beneficial effects of the present invention compared with the prior art are as follows:

[0016] First, high-density clam farming can effectively reduce the concentrations of suspended particulate matter, ammonia nitrogen, and nitrite in seawater ponds, reducing the frequency of water changes and the risk of disease. Large-sized clams enhance the system's stability against temperature and salinity fluctuations, preventing large-scale mortality of a single size due to environmental fluctuations.

[0017] Secondly, compared with traditional fish and shrimp farming, mixed farming of fish and shrimp is prone to lead to the accumulation of leftover bait and deterioration of the bottom soil, requiring frequent use of chemical bottom improvers, while mixed farming of clams reduces chemical inputs through biological self-purification.

[0018] The polyculture model of large-scale Manila clams with fish and shrimp leverages the principles of ecological niche complementarity and material circulation to efficiently achieve the synergistic effect of "using water to cultivate clams, using clams to regulate water, and using fish to control diseases." This innovative model not only significantly reduces aquaculture costs and improves economic returns, but also significantly reduces nitrogen and phosphorus emissions, providing solid support for the steady development of the marine aquaculture industry towards sustainable, intensive, and clean development. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Graph showing changes in dissolved oxygen in each enclosure during the culture period;

[0020] Figure 2 pH changes in each enclosure during the culture period;

[0021] Figure 3 Ammonia nitrogen changes in each enclosure during the breeding period;

[0022] Figure 4 Changes in total nitrogen in each enclosure during the breeding period;

[0023] Figure 5 Changes in total phosphorus in each enclosure during the breeding period;

[0024] Figure 6 Growth changes of Japanese shrimp in each enclosure during the culture period;

[0025] Figure 7 Growth changes of Manila clams in each enclosure during the culture period;

[0026] Figure 8 Growth changes of Takifugu chrysantha in each enclosure during the culture period; DETAILED DESCRIPTION

[0027] The technical solution of the present invention is further explained below through examples, but the protection scope of the present invention is not limited in any form by the examples.

[0028] Example 1

[0029] A method for ecologically regulating water quality in a multi-trophic-level fish, shrimp, and shellfish polyculture seawater pond, the method comprising the following specific steps:

[0030] 1) Select a pond with a sandy muddy bottom that is easily accessible for drainage and free of freshwater or sewage. Seal the pond for drying, disinfect it, remove sludge and weeds, repair the pond edges and banks, and unclog the drainage system. Build a 3m x 3m experimental enclosure within the pond. Do not change the water throughout the culture process, and maintain a water depth of 1.3m.

[0031] 15-30kg / hm 2 Sprinkle bleach to kill pests and improve the bottom soil. After aeration for 24 hours, press 15-30kg / hm 2 Use tea dregs for secondary disinfection, which also fertilizes the water and prevents black sea melon seeds. Continuous oxygenation is applied during this period. When the seawater is oily green (including blue-green, yellow-green and bean green) or brown (including yellow-brown, reddish-brown and tea-brown), with moderate transparency between 20 and 30 cm, with obvious daily and monthly changes, the water body contains a high content of plankton and good dissolved oxygen conditions.

[0032] Selection of seedlings: Chrysanthemum yellow pufferfish: Choose overwintering fish species with no injuries on the body, quick reactions, uniform size, good fatness, and no parasites after microscopic examination, with a body length of 6-7cm.

[0033] Japanese shrimp: Choose shrimp fry that are more than 1-1.5cm long, fat, active, transparent, neatly sized, not sticky with dirt, and tested to be free of white spot virus.

[0034] Manila clams: Select healthy, undamaged, uniform seedlings. Stock the seedlings with Japanese shrimp first on the first day, followed by Manila clams on the second day. On the fourth day, after the Manila clams have burrowed into the sand and the Japanese shrimp have regained their vitality, add the chrysanthemum-colored pufferfish. This prevents the chrysanthemum-colored pufferfish from preying on the Japanese shrimp and Manila clams. Two different experimental schemes were designed: Scheme 1 employed a mixed culture system with two sizes of Manila clams of the same density; Scheme 2 employed a mixed culture system with Manila clams of the same size at different densities, with the same size and density. The mixed culture system served as the control group, with three replicates for each treatment.

[0035] Table 1. Composition of different experimental groups

[0036]

[0037] 2) Pufferfish Food: Mainly a complete compound feed, fed 1-3 times daily. Depending on water temperature and fish size, the daily feed rate should be 3%-20% of the fish's body weight. Fresh feed should be placed in a fixed feeding table. Check feeding daily and adjust the amount as needed. Japanese Shrimp Food: Initially feed the pond with biological bait and compound feed three times a day, with morning and evening feedings accounting for 60% of the normal daily feed intake. This is to encourage the Japanese shrimp to feed on the biological bait in the pond. Manila Clam Food: Mainly a basic biological bait cultivated in the pond water prior to stocking.

[0038] 3) Patrol the pond daily, monitoring the growth, feeding, and activity of aquacultured organisms, and checking the water color. Use specialized tools to regularly monitor and record the growth of organisms. Promptly remove any remaining bait, feces, etc. from the pond to maintain a clean environment.

[0039] Water quality monitoring: Observe the water color and use a microscope to check the number and types of plankton to determine if the pond water is enriched. Enriched water is dark green (blue-green, yellow-green, bean green) or brown (yellow-brown, reddish-brown, tea-brown), rich in plankton, and high in dissolved oxygen. Abnormal water colors such as black or red indicate water quality problems, which can lead to oxygen depletion, affect plankton, deteriorate water quality, and endanger the health of aquatic animals.

[0040] Reasons for water quality deterioration: excessive feeding, weather changes, high organic matter content in the pond bottom, and imbalance in the nitrogen-phosphorus ratio affect algae growth, leading to deterioration of water quality.

[0041] Improvement measures: Feed fish properly, control stocking density, disinfect fish properly, use biofloc technology to maintain a stable water environment, and use biological agents such as Bacillus and carbon sources to achieve the effects of water purification and enrichment.

[0042] Carbon source and Bacillus spore dosage standards: The entire aquaculture cycle is 120 days, divided evenly into three periods: early, mid, and late. Each period is 40 days, with carbon source dosage every 15 days in the early, mid, and late periods. The dosage is 300-400g of carbon source (vital carbon, Xiamen Liyang Aquatic Technology Co., Ltd.) per mu, and 100-150g of Bacillus spores (purchased from Xiamen Liyang Aquatic Technology Co., Ltd.) per mu.

[0043] 4) Regularly collect samples and measure water quality indicators: When stocking, use a water sampler to collect surface, middle and bottom water samples of each aquaculture system as initial samples, and then collect samples every 15 to 30 days. Measure water temperature, salinity, dissolved oxygen and pH on site. Take 1000 mL of water sample and filter it through a 0.22 μm microporous membrane. The filtrate is used for ammonia nitrogen (NH 4+ ), total dissolved nitrogen (DTN) and total dissolved phosphorus (DTP) concentrations.

[0044] 5) If Figure 1-8 As shown in the figure, when comparing different sizes, the large size yxb2 group was better than the small size yxb1 group; when comparing different densities, the high density yxb3 group was better than the low density yxb2 group. Both groups were higher than the control group YX (fish and shrimp). The conclusion is that from the perspective of density, the high density group is the best. Therefore, the use of large size and high density Manila clams for mixed culture has the best effect.

[0045] In summary, the present invention reduces nitrogen and phosphorus emissions by 30% by constructing a four-dimensional ecological cycle system of "fish excretion - shrimp disturbance - shellfish purification - microbial degradation". For specific data indicators, please refer to the attached figure.

[0046] In practical applications, those skilled in the art can reasonably select other parameters within the technical solution of the present invention, but they are substantially the same as the technical solution protected by the present invention and still fall within the scope of protection of the present invention.

Claims

1. A method for regulating water quality ecologically in a multi-trophic-level fish, shrimp, and shellfish polyculture seawater pond, characterized in that: The method is specifically as follows: Step 1: After cleaning the pond, add seawater to the pond and cultivate the water; Step 2: On the first day, first release Japanese shrimp, with a size of 1-1.5 cm and a stocking density of 44,000-46,000 shrimp / mu; On the second day, add Manila clams and select healthy, undamaged, uniform-sized clams with fresh colors. The size is 135 clams per kilogram, and 70,000 to 75,000 clams per mu. On the fourth day, add healthy chrysanthemum yellow pufferfish of uniform size, 6-7 cm in length, at a stocking density of 1,000-1,200 per mu. Step 3, (1) breeding management: feed the pufferfish with complete feed, with the daily feeding amount being 3%-20% of the fish body weight; Shrimp bait: In the early stage, feed the biological bait and compound feed in the pond, and the amount fed in the morning and evening accounts for 60% of the normal breeding feeding amount; There is no need to feed artificial feed to Manila clams; (2) Carbon source and Bacillus spores feeding standards: From the start of cultivation to the 40th day, carbon source and Bacillus spores are fed every 15-20 days, every 10-15 days from the 41st to the 80th day, and every 7-10 days from the 81st to the 120th day. The dosage is 300-400 g of carbon source per mu and 100-150 g of Bacillus spores per mu. (3) No water changes during the entire breeding period.

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