A Method for Overwintering Micropterus salmonides under Ice

Abstract

The present invention provides a method for overwintering Micropterus salmonides under ice, which includes: selecting a pond with a water depth of more than 2.5 meters, and during the frozen winter, the water depth under the ice in the pond should always reach more than 1.5 meters; arranging microporous aeration and oxygenation equipment in the pond to oxygenate the water body and at the same time adjust the water temperature of the water body; when the water temperature of the water body is 7 - 10°C, oxygenate the water body when the air temperature is higher than the water temperature, and at the same time increase the water temperature of the water body and feed compound feed; stop feeding when the water temperature of the water body is below 7°C, and oxygenate the water body when the air temperature is lower than the water temperature; control the water temperature of the water body above 1°C; after the ice is sealed, the water temperature of the water body can be controlled at 1.3 - 2°C. An under-ice overwintering experiment was carried out in a certain place in Jilin Province, and the overwintering survival rate was more than 95%.

Description

Technical Field

[0001] The present invention belongs to the field of aquaculture, and particularly relates to a method for overwintering Micropterus salmoides under ice. Background Art

[0002] Micropterus salmoides, also known as California bass or black bass, belongs to the order Perciformes, suborder Percoidei, family Centrarchidae, genus Micropterus, and species Micropterus salmoides.

[0003] The mature individuals of Micropterus salmoides generally have a body length between 25 and 35 cm, and can reach up to 50 cm at most. The body is spindle-shaped, laterally compressed, with slightly thicker dorsal meat, and the cross-section is oval. The mouth slit is large, obliquely split, and the jaw can stretch. The teeth are fine velvet-like teeth and are relatively sharp. In nature, it likes to inhabit the shallow waters of lakes and ponds with sandy or sandy-muddy bottoms, low turbidity, relatively warm water temperatures, and clear water quality. After artificial breeding and domestication, it has been able to adapt to slightly fertile water quality. In ponds, it generally moves in the middle and lower water layers and often hides in the plants.

[0004] Micropterus salmoides can survive within the water temperature range of 1 - 36°C. Currently, the publicly available information shows that Micropterus salmoides starts to feed above 10°C. Micropterus salmoides is ferocious by nature and feeds on fish, shrimps, crabs, and other invertebrates in natural waters, and is a typical carnivorous fish. The initial feeding baits for newly hatched fry are rotifers and nauplii. Juvenile fish mainly feed on cladocerans, and young fish mainly feed on copepods. Juvenile fish with a length of 3.5 cm start to feed on small fish. When food is scarce, cannibalism often occurs. After patient domestication, it can feed on pellet feeds. It is suitable for farming in lakes, reservoirs, and freshwater ponds.

[0005] Micropterus salmoides was first introduced and developed in Guangdong Province. It also likes relatively warm water bodies in the natural environment, and the farming effect has always been good in Guangdong Province. When Micropterus salmoides was gradually introduced from south to north, it was found that the longer the freezing period is towards the north, the worse the overwintering effect is. When introduced north of the Yellow River, it was found that the survival rate of overwintering became worse and worse. Especially when introduced to Liaoning Province, there were no successful cases of overwintering. Therefore, currently, the academic community generally believes that Micropterus salmoides prefers high temperatures and cannot adapt to the water temperature of the under-ice water bodies in the northern regions (generally below 4°C). To enable Micropterus salmoides to overwinter safely in the northern regions, it is necessary to find ways to increase the temperature of the overwintering water body.

[0006] The overwintering period in the area north of the Great Wall is very long. In Jilin Province, it is as high as more than 130 days, and the water surface is covered with a thick ice layer, with the ice layer thickness generally being 50 - 80 cm. It is impossible to raise Micropterus salmoides on a large scale.

[0007] Currently, the common practice in the northern regions is to move the Micropterus salmonides indoors for overwintering with heating, or in greenhouses, using groundwater to replenish water and raise the temperature, so as to increase the water temperature, prevent the water surface from freezing, and supplement oxygen at the same time, thus avoiding the use of aerators for oxygenation because oxygenation by aerators will reduce the water temperature.

[0008] In Tianjin area, the common methods for the overwintering of Micropterus salmonides are overwintering in greenhouses, using groundwater to replenish water and raise the temperature, and overwintering in open water; the survival rate of Micropterus salmonides overwintering is about 80%.

[0009] In Liaozhong area, the experience of Tianjin (raising in greenhouses, using groundwater to replenish water and raise the temperature, and overwintering in open water) was adopted. After many trial cultures, no success was achieved. Currently, there are no successful cases north of the Great Wall. Summary of the Invention

[0010] The purpose of the present invention is to provide a method for the under-ice overwintering of Micropterus salmonides to solve the problem that Micropterus salmonides cannot overwinter under ice.

[0011] A method for the under-ice overwintering of Micropterus salmonides includes:

[0012] 1) Pond conditions: The water depth of the pond reaches more than 2.5 meters. During the frozen winter, the water depth under the ice in the pond should always reach more than 1.5 meters; Micro-pore aeration equipment and water temperature sensors are arranged in the pond, and a temperature control switch is installed on the micro-pore aerator.

[0013] 2) Release Micropterus salmonides in spring and overwinter in the original pond.

[0014] 3) Management before ice sealing:

[0015] a. When the water temperature of the water body is 7 - 10 °C and the air temperature is higher than the water temperature, oxygenate; feed compound feed.

[0016] b. When the water temperature of the water body is below 7 °C, stop feeding, and oxygenate when the air temperature is lower than the water temperature.

[0017] 4) Management after ice sealing:

[0018] a. In the early winter period, oxygenate when the air temperature is below 0 °C.

[0019] b. In the severe winter period, when the water temperature of the water body is close to 1 °C, stop oxygenating; control the water temperature of the water body above 1 °C.

[0020] In the extremely cold period, oxygenate at the highest air temperature of the day, generally from 1 to 4 p.m., to ensure the oxygen concentration.

[0021] 5) Management after the ice surface thaws:

[0022] a. Before the water temperature of the water body reaches 7 °C, oxygenate when the air temperature is lower than the water temperature.

[0023] b. When the water temperature of the water body reaches 7°C, start feeding compound feed; when the air temperature is higher than the water temperature, increase the oxygen content;

[0024] 6) Keep the dissolved oxygen in the water body always above 5 mg / L;

[0025] The water temperature of the water body described in step 4) is not lower than 1.3°C;

[0026] The water temperature of the water body described in step 4) is 1.3 - 2°C;

[0027] The overwintering density per mu is 1000 kg / mu;

[0028] The compound feed is based on conventional compound feed, with multiple vitamins doubled, and polysaccharides and Chinese herbal medicines for protecting the liver added additionally.

[0029] The present invention provides a method for overwintering Micropterus salmonides under ice, which includes: selecting a pond with a water depth of more than 2.5 meters, and during the frozen winter, the water depth under the ice in the pond should always reach more than 1.5 meters; arranging a microporous aeration oxygenation device in the pond to oxygenate the water body, and at the same time adjusting the water temperature; when the water temperature of the water body is 7 - 10°C, oxygenate when the air temperature is higher than the water temperature, and at the same time increase the water temperature and feed compound feed; stop feeding when the water temperature of the water body is below 7°C, and oxygenate when the air temperature is lower than the water temperature; control the water temperature above 1°C; after the ice is sealed, the water temperature of the water body can be controlled at 1.3 - 2°C. The inventor conducted experiments in a certain place in Jilin Province, and the overwintering survival rate was more than 95%. Brief Description of the Drawings

[0030] Figure 1 Photos of a large number of dead Micropterus salmonides after overwintering under ice in a certain place in Northeast China. Detailed Embodiments

[0031] Through years of research and experiments, the inventor found that Micropterus salmonides start to feed on live food when the temperature is above 10°C, start to feed on compound feed at 7°C, and can normally feed on compound feed at 8°C. During normal life, the dissolved oxygen in the water is required to be above 4 mg / L, and fry will show floating heads when the dissolved oxygen is lower than 2 mg / L. Micropterus salmonides has a wide adaptability to salinity and can live not only in fresh water but also in brackish water with a salt content of less than 10%. The age of sexual maturity is generally 1 year old, but the reproductive effect of individuals at 2 or 3 years old is better.

[0032] Example 1 A Method for Overwintering Micropterus salmonides under Ice

[0033] A method for overwintering Micropterus salmonides under ice, which includes:

[0034] 1) Pond conditions: The water depth of the pond reaches more than 2.5 meters. During the frozen winter, the water depth under the ice in the pond should always reach more than 1.5 meters; arrange a microporous aeration oxygenation device and a water temperature sensor in the pond, and install a temperature control switch on the microporous aerator;

[0035] 2) Release Micropterus salmonides in spring and overwinter in the original pond. Micropterus salmonides are fierce by nature and are extremely vulnerable to injury when being netted, which will affect the survival rate during overwintering.

[0036] 3) Management before ice sealing:

[0037] a. When the water temperature of the water body is below 10°C, gradually reduce the feeding amount of compound feed; aerate during the period with the highest temperature of the day; control the dissolved oxygen in the water body at the maximum concentration; reduce the rate of water temperature drop.

[0038] b. Stop feeding when the water temperature of the water body is below 7°C. Aerate with an under-ice microporous aerator during the period with the lowest temperature at night (early morning, temperature below 7°C). The purpose is to quickly reduce the water temperature of the water body and keep the water temperature at a low level; control the dissolved oxygen in the water body at the maximum concentration.

[0039] 4) Management after ice sealing: Aerate with an under-ice microporous aerator. Stop aerating when the water temperature of the water body is close to 1°C; start aerating with the aerator when the water temperature reaches 2°C; control the water temperature of the water body at >1°C and ≤2°C; when the water temperature of the water body is 2°C, the microporous aerator works, and when the water temperature of the water body drops to close to 1°C, the aerator stops working.

[0040] 5) Management after the ice surface thaws: After the ice surface thaws, aerate during the period with the lowest temperature at night to keep the dissolved oxygen in the water body always above 5 mg / L; before the water temperature of the water body reaches 7°C, try to control the water temperature of the water body at a relatively low level.

[0041] 6) Start feeding compound feed when the water temperature of the water body is 7°C; aerate during the period with the highest temperature in the afternoon every day, and control the dissolved oxygen in the water body at the maximum concentration.

[0042] When the water temperature of the water body is 7°C, quickly increase the water temperature.

[0043] The water temperature of the water body described in step 4) is not lower than 1.3°C.

[0044] The overwintering density per mu is 1000 kg / mu.

[0045] After the overwintering pond is sealed with ice, clear the snow in time, and the area of the transparent ice exposed on the ice surface accounts for more than 60% of the total frozen area of the pond.

[0046] The compound feed mentioned above, on the basis of feeding conventional compound feed, doubles a variety of vitamins and additionally adds polysaccharides and Chinese herbal medicines for protecting the liver.

[0047] Example 2 Example of overwintering culture of Micropterus salmonides

[0048] In 2021, we conducted an overwintering experiment on Micropterus salmoides in a 5,000-square-meter pond at the experimental base of the Aquatic Product Quality and Safety Testing Center in Changchun City. The average water depth of the overwintering pond was 3.0 meters, and the pond was lined with an anti-seepage membrane, with basically no water seepage or leakage. The water depth under the ice could always reach more than 1.5 meters.

[0049] The aquaculture pond was equipped with a 1.5-kilowatt microporous aerator, which could be turned on at any time to oxygenate the pond and discharge toxic gases.

[0050] 3. Source of fish

[0051] The Micropterus salmoides were fish cultured in the original pond; because Micropterus salmoides are ferocious by nature, they are extremely easy to get injured when being netted, which will affect the overwintering survival rate.

[0052] 4. Method

[0053] 1) Management before ice sealing

[0054] Scientific feeding: Keep feeding until the fish no longer feed (below 7°C) before the overwintering of Micropterus salmoides. Store enough energy for the overwintering fish; regularly add liver-protecting drugs to the bait to keep the hepatopancreas of Micropterus salmoides basically normal, enhance the immunity of the fish, and ensure safe overwintering;

[0055] Scientific water quality regulation: Observe the water quality changes daily;

[0056] 2) Management after ice sealing

[0057] Responsibility system: The overwintering pond is managed by a dedicated person, and the water temperature and dissolved oxygen of the overwintering pond are measured every day;

[0058] Timely snow sweeping: Sweep the snow in time during snowfall to ensure that the clear ice area exposed on the pond ice surface always accounts for more than 60% of the total frozen area of the pond;

[0059] Water quality monitoring: Take water samples once every seven days to check the water quality, water color, and activities of the fish in the pond;

[0060] According to the method of Example 1, use the aerator to increase or decrease the temperature. Increase the temperature when it is 7°C - 10°C and try to adjust it to the highest. Decrease the temperature when the water temperature is below 7°C and try to lower the water temperature to the lowest; during the severe winter period, the water temperature in the winter pond has been hovering at a very low temperature. During the severe cold period, oxygenate at the highest temperature of the day, generally from 1 to 4 pm; to ensure the oxygen concentration; the water temperature of the water body in the entire severe winter period is 1.3~1.8 degrees Celsius. Ensure that the dissolved oxygen in the water body of the overwintering pond is always above 5 mg / L; Micropterus salmoides have no appetite for food, so they can overwinter safely.

[0061] II. Test results

[0062] An overwintering experiment was conducted in the winter of 2021. In May 2022, after testing, the overwintering survival rate was more than 95%.

Claims

1. A method for overwintering Micropterus salmonides under ice, which includes: 1) Pond conditions: The water depth of the pond reaches more than 2.5 meters. During the ice-bound winter, the water depth under the pond ice should always reach more than 1.5 meters; Install microporous aeration and oxygenation equipment and water temperature sensors in the pond, and install a temperature control switch on the microporous aeration and oxygenation equipment. 2) Release Micropterus salmonides in spring and overwinter in the original pond. 3) Management before ice sealing: a. When the water temperature of the water body is 7 - 10 °C and the air temperature is higher than the water temperature, oxygenate; Feed compound feed. b. Stop feeding when the water temperature of the water body is below 7 °C, and oxygenate when the air temperature is lower than the water temperature. 4) Management after ice sealing: a. In the early winter period, oxygenate when the air temperature is below 0 °C. b. In the severe winter period, stop oxygenating when the water temperature of the water body is close to 1 °C, and control the water temperature of the water body above 1 °C. 5) Management after the ice surface thaws: a. Oxygenate when the air temperature is lower than the water temperature before the water temperature of the water body reaches 7 °C. b. Start feeding compound feed after the water temperature of the water body is 7 °C; Oxygenate when the air temperature is higher than the water temperature. 6) Keep the dissolved oxygen in the water body always above 5 mg / L.

2. The ice-underwintering method for Micropterus salmonides according to claim 1, characterized in that: The water temperature of the water body described in step 4) is not lower than 1.3 °C.

3. The method for overwintering Micropterus salmonides under ice according to claim 2, characterized in that: The water temperature of the water body described in step 4) is 1.3 - 2 °C.

4. The method for overwintering Micropterus salmonides under ice according to claim 3, characterized in that: The overwintering density per mu is 1000 kg / mu.

5. A method for overwintering Micropterus salmonides under ice according to claim 1, 2, 3 or 4, characterized in that: The compound feed is based on the conventional compound feed, with multiple vitamins doubled, and polysaccharides and hepatoprotective Chinese herbal medicines added additionally.

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