Tilapia is commonly known as: African crucian carp, non-crucian carp, Vietnamese fish, Nanyang crucian carp and so on. It used to refer to the non-crucian carp species in Mozambique as the origin of the model: the non-crucian carp in Mozambique is now the collective name of several cichlids such as non-crucian carp and non-crucian carp in mouth; English collectively refers to tilapia. At present, it is the focus of freshwater aquaculture in the world, and it is considered as one of the main sources of animal protein in the future. Below, I will provide you with the artificial breeding techniques and methods of African crucian carp, hoping to help you!

Artificial culture technology of African crucian carp and spring breeding technology

The suitable water temperature for tilapia culture is 22 ~ 23℃, and it usually lays eggs naturally after mid-May. In order to seize the season, make full use of light, heat and bait resources, and improve the output of aquaculture, it is necessary to adopt artificial warming, strengthen cultivation and advance spring breeding, so that tilapia can lay eggs and hatch fry in mid-April. Specific measures are as follows.

Selection and cultivation of parent fish

Select parent fish with good maturity, and put them into spawning pond to strengthen cultivation in mid-March. The spawning pond can choose wintering pond. Generally, every square meter spawning pond is stocked with 6 parent fish, with the male-female ratio of 2∶ 1 or 3∶ 1, and the water is changed regularly.

2. Heating and feeding management

The water temperature in the pond should be controlled above 23℃, and the water quality should be fat, lively and cool. The feeding amount can be determined according to the water temperature, water quality and fish growth. Generally, the daily feeding amount in static pond is 2% of the fish's weight, and that in moving pond is 3%. At the same time, we should always observe the activity of fish and the degree of gonad development, and make records.

lay eggs

There are obvious differences in body color between male and female tilapia. Male fish in estrus swim around the pool, looking for a place to nest. The nest is pot-shaped, with a diameter of 30 ~ 40 cm and a depth of about 10 cm. After the nest is built, the male fish will tease the female fish from time to time and stop the female fish from pairing in the nest. When the water temperature reaches 22 ~ 23℃, the female fish can lay eggs. When laying eggs, the abdomen of the female fish clings to the bottom of the nest, and the male fish guards the nest. After laying eggs, the female fish immediately sucks the eggs into her mouth, and the mandibular protrusion is cystic. The male fish immediately enters the nest to excrete semen, and the female fish sucks the semen into her mouth with water. The egg is fertilized in the mouth.

Hatched seedlings

The fertilized eggs of tilapia hatch in the mouth of the female fish and rotate with the breath of the female fish, which not only has the protection of the mother, but also has a good incubation environment. When the water temperature is about 30℃, the fry will hatch in about 4 ~ 5 days. It takes about 7 days at 25℃.

Among many tilapia seedlings, it is generally believed that the seedlings bred by interspecific hybridization of tilapia have the characteristics of fast growth, large size, good cold tolerance and high male rate, which is widely recognized by farmers. Its commodity names mainly include: Oni, Oza, Wu Guoyu, Androgyny, etc. However, the quality of fry produced by different fry production units varies greatly. Farmers should select a seedling with the fastest growth rate and the highest male plant rate from many varieties through breeding.

The parthenocarpy tilapia produced in China objectively did not reach the male rate of 100%. In the breeding production, there are more or less inferior offspring, which increases the breeding density, consumes a lot of feed, and even fails to meet the commodity specifications (its value is only about 20% of the normal product, so it is called cat fish), which seriously affects the output and benefit of tilapia breeding production. In order to solve this problem, there are the following measures:

1. Breeding producers should be equipped with enough standard thick ponds for secondary fry. The standard thickness of primary fry is about 20-50g, and that of secondary fry is about 200-400g. Then, the males are sorted and put into the ponds to develop commercial fish. Can this solve the problem of breeding? Catfish? Too many problems can avoid the waste of water surface in the early stage of aquaculture.

2. Manually remove inferior offspring on a regular basis. According to the characteristics of tilapia seedlings swimming in groups, in its breeding season, inferior seedlings are collected and removed from the pond every 2 ~ 3 days.

3. Moderate stocking of carnivorous fish. After the tilapia fry are stocked, some ferocious carnivorous fish such as Silurus meridionalis, barracuda and spotted snakehead (the stocking specifications are based on the tilapia that cannot be stocked) are appropriately stocked to prey on the offspring of tilapia culture. Farmers in Gaozhou usually mix 20 catfish per mu, and if the pond is not cleaned, mix 20 spotted snakeheads per mu.

4. Breeding in batches, and cleaning the pond after harvest. Except the small reservoir in the mountain pond, it is really impossible to clean the pond with dry water. In general, the traditional way of catching and releasing is changed, and batch farming is carried out, and the pond is cleaned after harvest.

Key points of aquaculture technology

Many places actively implement the strategy of base production of tilapia, vigorously promote the main cultivation of tilapia in large waters, and apply the technology and management mode of high-yield and high-efficiency cultivation of tilapia in ponds to the deep development of large waters, completely changing the production situation of extensive and extensive cultivation, low yield and low efficiency in large waters, and greatly improving the production potential. Farming tilapia mainly in large water surface can obtain remarkable economic benefits, and the water body is stable and the rent is low. As long as it is not used as drinking water source and other purposes, scientific development can get better harvest. Several technical points of tilapia culture on large water surface are briefly described as follows:

1.

This work is very important, but it is often ignored by farmers. Its function is to sterilize, eliminate enemy harm, improve the breeding environment, effectively prevent the damage of large and fierce fish to breeding varieties, and reduce the competition between wild miscellaneous fish and free-range fish for feed and water space. Drain the water as far as possible to the large water surface with good water source and easy drainage, and the dry pond cleaning effect is the best. Adding 50-75 kg/mu of quicklime to make slurry, sprinkling it all over the pond while it is hot, exposing it to the sun for a while, and then injecting water; The large water surface with poor water source and difficult drainage can be used to clean the pond. When the water level is as low as possible, when the water depth is 1.0m, 40 ~ 50 kg/mu of tea cake is applied to the whole pond, and the effect of cleaning the pond is also very good. In practice, it is necessary to fish out dead fish in time and bury them far away, so as not to affect the water quality.

2. Cultivate water quality

Comprises two stages of aquaculture water quality in the early stage and aquaculture water quality in the late stage. In the early stage of aquaculture, the average tail weight of the main fish species was before 0.25kg, and the palatability of basic bait organisms was increased by fertilizing water, thus reducing the cost of aquaculture. In the past, farmers underestimated the investment in large-scale farming, and simply fed fish, and they could cope at first. However, with the growth of fish and the increase of fish intake, it is difficult to meet the feeding needs of normal growth of fish due to insufficient funds, and the products can not meet the specifications, resulting in losses; In recent years, in order to cope with the ups and downs of aquatic products market, we have vigorously promoted the fish farming model combining fertilizer with feed, ensuring the steady development of fishery production. The capital turnover of fish farming on large water surface is large, and fish farming with fertilizer and water can not only reduce costs, but also resist risks.

It is worth noting that all kinds of manure, including livestock manure, green manure, sugar mill filters and so on. Before being applied to water, it should be disinfected, sterilized and treated harmlessly. In particular, livestock manure must be fermented and decomposed, then disinfected with 1% ~ 2% quicklime water, and controlled at the source of livestock feed, drugs and additives to prevent harmful substances from affecting water quality through manure; The filter mud of sugar factory is a new fertilizer source for fishing, which contains a lot of organic debris, which can not only fertilize water but also be eaten directly by fish, with good effect. The aquaculture water quality in the later period of aquaculture means that no organic fertilizer can be applied for 3 months before fish are caught. The large water surface with good water source can be replaced with fresh water by injecting more water, and the large water surface with inconvenient water source can be used to remove organic pollutants in aquaculture water, reduce harmful substances such as ammonia nitrogen, hydrogen sulfide and nitrite, stabilize the pH value of water body, inhibit the growth and reproduction of pathogenic microorganisms, increase dissolved oxygen in water body, and maintain the freshness and vitality of water body. At the same time, funds can be concentrated to strengthen late feeding and promote the rapid growth of fish.

3. Choose improved varieties

After many years of production practice, Nile tilapia has become the largest fish culture species in Gaozhou with its advantages of cold tolerance, fast growth and high male fish rate. Nile tilapia has high technology content, so it is difficult to produce fry with good body shape and high sex rate. If the male fish rate of Nile tilapia is not high, a large number of larvae will breed by themselves after four months of stocking, and the breeding density will increase rapidly, and a large number of larvae will consume oxygen and materials to seize space, which will lead to breeding difficulties. Therefore, it is an important link to cultivate high-quality Nile tilapia with high sex ratio. In order to ensure the quality of tilapia fry, farmers should go to tilapia breeding units that have obtained aquatic seedling production licenses and the public generally reflect that the trial breeding effect is good. In actual production, it is unrealistic to make Nile tilapia fry all male. The solution is to raise some carnivorous fish for killing, such as 100 ~ 300 freshwater pomfrets per mu, which can achieve certain results.

4. Reasonable stocking

Aquatic products require high quality and good price. When I say high quality, I mean that the products should meet the specifications and grades. In recent years, the purchase and sale of tilapia are mainly divided into four specifications and grades, namely, the average tail weight is below 0.5kg, 0.5 ~ 0.8 kg, 0.8 ~1.1. 1kg, and there are four corresponding product prices, and the price difference of each adjacent commodity is about 65430. As far as the production situation is concerned, the cost of simply feeding feed to produce products with average tail weight less than 0.5kg is about 1 yuan /kg. Therefore, aquaculture production is in urgent need of reasonable stocking and greatly improving product specifications. Our recommended stocking density is 1000 ~ 1500/mu, freshwater pomfret 100 ~ 300/mu, silver carp/bighead carp 50 ~ 80/mu and bighead carp 30 ~ 50. If the breeding conditions are poor, the main tilapia shall not exceed 1000/mu. The actual production shows that the yield of sparse planting is not lower than that of dense planting. After sparse planting, the yield per mu of many large water surfaces has reached more than 2t, and the product specifications and breeding profits have been improved simultaneously. The average profit per mu is more than 2,000 yuan, and the highest profit per mu is more than 4,000 yuan.

5. Scientific achievements

Fishing and harvesting are very important in large-scale aquaculture. A few years ago, there was a reservoir with an area of several hundred mu, and its main species, Nile tilapia, reached the commodity specifications as a whole. Because the intermittent fishing time is too long, the income from production has to be used for the feed input of fish in the pond, and the fish in the pond ate the listed fish, which eventually caused serious losses. Practice has proved that when fishing 1 day, fish do not eat for 3 days, and the food intake is abnormal within 1 week. Even if the fish is eaten, the consumption of materials will not increase. Moreover, long-term trawling is easy to cause fish body damage or even death, and the fish body gradually becomes thinner and devalues.

Therefore, catching fish quickly when the time is ripe can ensure the breeding income. In order to do this, we must pay attention to the following problems: first, the specifications of stocked fish should be as consistent as possible and fed evenly to ensure that most individuals reach the ideal commodity specifications at the same time; Second, choose the right fishing spot, and set the place where the feed is fed in a place where it is easy to catch fish, so as to ensure the density of fish in the fishing area and shorten the fishing period; The third is to pay attention to market information and strive for timely harvest in good times.

6. Continuous support mode

Two-season tilapia continuous culture mode: large-scale tilapia fry are graded, and a certain number of filter-feeding silver carp, bighead carp, herbivorous grass carp and carnivorous herring are mixed in the adult fish culture pond and fed together. When tilapia meets the market specifications, it will be caught and sold. Whether it is sold or not depends on the size of the cultured fish.

The second batch of large-scale tilapia species will be stocked in the dry pond immediately, and the dry pond will be carried out after the tilapia reaches the market specifications for sale. The above two-season tilapia continuous culture technology is a kind of culture mode based on the successful experience of tilapia farmers in Gaozhou City, Maoming. After tilapia is cultured for two seasons, the pond will be cleaned.

This kind of culture mode makes full use of pond culture space, saves culture time, returns funds quickly, and the products meet the export healthy culture standards. It can also improve the economic benefits of mixed culture of silver carp and bighead carp, relatively reduce the rental cost of tilapia breeding ponds and increase the yield of tilapia per unit area. It is the first choice for tilapia farmers in Gaozhou, Maoming, with local characteristics. Generally, tilapia can overwinter naturally, and professional fishing teams and other conditions can make use of this farming model to produce good economic benefits.

Running water overwintering

Fish stocking

In tilapia culture, firstly, the pond was cleaned and disinfected with bleaching powder to make the concentration of pond water reach 2ppm. After dosing, the water inlet should be blocked so that the liquid medicine can be soaked in the pool for more than 24 hours. When stocking, open the water inlet and let the running water dilute the concentration of the liquid medicine in the pond. Fish species can only be stocked after pond water exchange 1 time. Before putting the fingerlings into the inflow pond, soak them in 2% salt solution for 5 ~ 10 minutes, or in malachite green solution with a concentration of 8 ~ 10 ppm for 10 ~ 15 minutes.

The suitable stocking specification is 25 ~100g per tail, and the fish with different specifications should be stocked separately for feeding management. The stocking density depends on the supply of warm water and the planned output, which can be calculated according to the formula: W=(A 1-A2)? Q)/(R？ v？ C) Testing. W is the fish quantity released per cubic meter of water (kg/ cubic meter); A 1 is dissolved oxygen in injected water (g/m3); A2 is to maintain the minimum oxygen consumption (g/m3) of tilapia, and q is the water injection (m3/hr); R is the oxygen consumption of fish (g/kg/hour); V is the volume of running water pool (cubic meters); C is a multiple of the planned growth. The minimum oxygen consumption A2 of tilapia is 1. 1.2g/m3, and r is 0.256 ~ 0.4g/kg body weight/hour.

Current management

Do a good job in cold prevention, feeding and water quality regulation. When the water temperature is kept at about 18 ~ 20℃ and below 18℃, fish are easy to get frostbite, move slowly and eat less, which is not conducive to wintering; When the water temperature is higher than 22℃, tilapia is active and its food intake increases. Excessive temperature will increase management troubles and is not conducive to wintering. During the wintering period, energy is mainly supplemented by artificial bait. When tilapia first entered the running pool, it ate very little because it didn't adapt to the environment. After 3-4 days, the food intake began to increase. At this time, the feeding amount should be increased in time, and each feeding should be induced by sound, and feeding should be started after the fish are concentrated.

In order to observe the feeding situation of tilapia and reduce the waste of bait, bait tables can be set up in the running pool, and the number of bait tables depends on the size of the running pool. Generally, every 15 square meter is provided with 1 0.5 square meter bait table, and the bait table is 35 ~ 40 cm away from the water surface. The feeding amount during the wintering period is mainly controlled according to the changes of water temperature, weather and fish species specifications. When the weather is clear and the water temperature is above 16℃, feeding should be started.

Feed the fish twice a day for 30 minutes. In addition, feed green feed (duckweed, ryegrass, etc.) properly. ) every day, and the green feed should be controlled at about 0.3 ~ 0.5% of the weight of fish in the pond. It is best to use granular bait as bait, and the thickness depends on the specifications of the fish; The raw materials must be fresh, and the storage time of bait should not exceed 15 days. Every 3 ~ 4 days, the sewage bottom valve in the running water pool should be opened to completely discharge the sewage.

The general practice is to drain the pool water to 80% dry, and concentrate the sewage at the sewage outlet through the activities of fish and the scouring of water flow. It is best to choose sunny days for sewage discharge, and try to avoid hurting fish. Combined with sewage discharge, we can observe the utilization of bait and the growth of fish. At the same time, the growth of fish (every half month 1 time) was measured, and the feeding amount in the second half month was calculated according to the growth of fish. Insist on patrolling the pond in the morning, middle and evening, and measure and record the changes of water temperature in the morning, middle and evening; Observe the activities of fish; Check whether the fish fence is damaged and remove the dead fish.

Artificial culture mode of African crucian carp pond culture mode

1. Pond conditions

The farm should be located in a sheltered, sunny, abundant water, fresh water, pollution-free, quiet and convenient place. The pond area is 3-5 mu, the water depth is 1.5-2 m, and the thickness of pond sediments is 20-30 cm. Each pond is equipped with 1 impeller aerator with power of 1.5 kW.

2. Clean the pond and fertilize it

Clean and disinfect the pond before releasing fish. Generally, in the first half of April, the pond is cleaned with 75 ~ 100 kg of quicklime per mu, and water is added to the depth of 1 m after 7 days, and then 300 ~ 400 kg of decomposed manure is applied per mu, and a small amount of green duckweed or red duckweed can be added.

3. Fish stocking

Every spring, when the water temperature rises and stabilizes above 15℃, winter seedlings are stocked. Generally, ponds are stocked with 1500 ~ 3000 kinds of fish, and 40 ~ 70 kinds of silver carp and bighead carp are mixed to control water quality. When mixed with other fish, 200 ~ 500 fish can be raised per mu.

Step 4 feed the bait

Tilapia can be fed 2-3 days after entering the aquaculture water surface. Tilapia has a wide range of food habits. In the case of artificial feeding, it can be fed with various feeds, such as wheat, corn and cake, which are all high-quality feeds. The content of protein in feed should be 32% ~ 35% at first, and the daily feeding amount should be 3% ~ 5% of the total weight of fish. When the individual size is about 200g, the feeding amount can be adjusted to 2% of the total weight of the fish, and the protein content in the feed can be ensured to be 27% ~ 29%. When the individual reaches about 300g, the tilapia enters the fastest growth period, the daily feeding amount is kept at 65438+ 0% ~ 2% of the fish weight, and the protein content in the feed is above 35%. Feed twice a day, at 8-9 am and 3-4 pm respectively.

5. Daily management

(1) Measure the water temperature and air temperature every morning, noon and evening, measure the pH value 1 time every week, and measure the transparency twice. Patrol the pond in the morning and evening 1 time.

(2) After the fishes enter the pond, the pond water should be kept dark brown with a transparency of 25-30cm. Generally, fertilization 1 time per week, and livestock manure 150 ~ 200 kg per mu each time. When the weather is clear and the water transparency is more than 30 cm, the amount of fertilization can be appropriately increased; When the water quality is too fat, we should reduce or stop fertilization and inject new water. In hot season, water is generally changed 1 ~ 2 times a week, and 20% ~ 30% of the pool water is changed each time.

(3) Adhere to healthy farming, standardize operations and prevent fish diseases. When the fry enter tang qian, soak the fish 10 ~ 15 minutes with 5% salt solution or 0. 1 mg potassium permanganate solution per liter. Every 65,438+00 ~ 65,438+05 days, 65,438+05 ~ 20kg of quicklime water is sprayed on each mu of the whole pond to adjust the pH value of the pond water to be slightly alkaline, and biological agents are used to improve the microbial structure of the pond and improve the water quality. When the dissolved oxygen is low and the fish has a slight floating head, turn on the aerator.

Paddy field culture mode

Land of fish and rice, can double harvest. Attention should be paid to scientific feeding in interplanting tilapia in rice fields.

1. Stocking preparation

After the completion of the paddy field project, two weeks before stocking, 75 ~ 100 kg of quicklime water per mu was sprayed in the fish ditch and ridge for disinfection, and the bottom of the ditch and ridge was raked 1 time the next day, so that lime slurry and silt were fully mixed. Before seedling release 1 week, fertilizer water from fermented animal manure was applied, with the dosage of 200 kg per mu, for cultivating natural bait in water.

2. Lead time

Generally, about 5 days after transplanting rice seedlings, the seedlings will be released when they turn green. In some places, in order to increase the growth period of fish, it is also an effective and good way to put fish in the fish ditch in mid-May and put them in the ground after the seedlings turn green.

3. Stocking method

Fish species should be selected with strong physique, strong activity, no damage and neat specifications. The stocking density should be reasonable. Generally, 200 ~ 300 tilapia fingerlings with specifications of 5 ~ 6 cm can be released per mu, and grass carp, carp and other fingerlings can be mixed 150 ~ 200. The specific stocking amount can be flexibly mastered according to paddy field conditions, water quality environment, irrigation and drainage conditions and management level.

4. Inventory operation

Fish should be disinfected before entering the pond. Generally, fish should be soaked in 3% ~ 5% salt water for 5 ~ 10 minute. Fish should be released in sunny morning or evening, but not in rainy day or sunny noon.

5. Feeding and fertilization

Generally speaking, Luo Fei, which is cultivated in rice fields, does not eat, and grows entirely by eating natural bait. However, the natural bait in rice field is limited, so it is suitable to feed some bait to accelerate its growth and improve its yield. Feed bait twice a day, and the feeding amount can be controlled within 2 hours after eating bait. There is no special requirement for applying base fertilizer and farmyard manure to fish-farming rice fields. Such as urea, ammonium sulfate, etc. They are all used as topdressing, and should be applied in small amounts several times, one and a half fields at a time. It is forbidden to apply fertilizer directly in the fish ditch.

Cage culture mode

Tilapia can be raised singly, mainly or together in cages. The species of fish should be large-sized, and the size of the fish in the box is generally 10 ~ 50g. When the dissolved oxygen is greater than 3 mg/L, the stocking density is 3 ~ 20 kg/m3.

Running water culture mode

Is tilapia cultured in high-density flowing water or not? Factorization? One of the main purposes of reproduction. The culture pond should not be too large, generally it is advisable to raise fish in 30 ~ 50 square meters, and keep the dissolved oxygen in the pond above 3 mg per liter. Intensive farming needs to be fed with compound feed with comprehensive nutrition, and the protein content of the feed should be about 30%. Feed it 5 ~ 6 times a day, and the feeding amount is 2.5% ~ 3% of the fish weight.

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