At present, the aquaculture industry faces various challenges, and the environment, disease, quality and safety all warn the farmers.2015The new "Environmental Protection Law", which was implemented in the year, strictly restricted the cultivation and sewage discharge. The Ministry of Agriculture and Rural Affairs (formerly the Ministry of Agriculture) pointed out that the direction of China's fisheries development is to reduce the amount of income, or to indicate that the aquaculture industry is time to transform. in2018At the annual fish and shrimp polyculture technology exchange meeting, Dr. Zhu Changbo from the South China Sea Fisheries Research Institute proposed that ecological farming is the way out for the aquaculture industry.
Zhu Changbo said that although low-salt shrimp farming has become the mainstream of shrimp farming in China, it still faces many difficulties, such as frequent diseases, risks and benefits are not proportional, and the breeding environment is deteriorating. After discussing solutions to these problems, "Positioning" is the best answer. He introduced several polyculture models of shrimp fish in low-salt ponds for farmers' reference.
Vannamei-Tilapia ecologically efficient polyculture model
Why do you want to mix tilapia in the shrimp pond? That is because tilapia has the advantages of miscellaneous feeding, rough feeding, fast growth, good meat quality, etc. It is the perfect partner for South American white shrimp. At present, there are two modes of mainstream prawn-tilapia polyculture: one is mainly shrimp, which feeds shrimp, and the tilapia is less than 50/mu, mainly to reduce shrimp disease, but the problem is to increase fishing. Process, economic efficiency is not obvious. The second is based on tilapia, feeding fish, low-density shrimp, round-trapping, tilapia, and shrimp as pure income. The effect is obvious. The problem is that the basis of the preservation is tilapia, but In recent years, tilapia diseases have been more serious and the market has been sluggish. This farming model has also been questioned.
In this regard, Zhu Changbo proposed a model of tilapia in the shrimp pond cage. This type of shrimp is suitable for placing seedlings with a density of 50,000/mu, and shrimps are placed in the pool for at least 15 days after the large-scale tilapia fry 10-15 cm. If the cage is around the pond, the stocking density of tilapia is suitable for 30-60/square; if the cage is in the middle of the pond, the stocking density of tilapia is suitable for 5-10/square. The culture process does not change water, and the water quality is regulated according to weather and water quality. This farming mode can make full use of the pond space, reduce the risk, easy to catch and fish, and separate the fish and shrimp to avoid tilapia to eat shrimp, if you do not feed the tilapia, it will also filter the particulate matter to regulate water quality. However, this farming mode should also reasonably control the mode of feeding and the size of the cage. Excessive amounts will increase the eutrophication of the water body. Insufficient tilapia output has limited effect on income.
Shrimp pond set fish cage schematic
Of course, Zhu Changbo also proposed shrimp-Tilapia direct polyculture mode. This model has certain optimizations for the traditional model, and the shrimp density is suitable.5Wanwei/Mu, shrimps into the pool at least15After the day, the target tilapia is placed. If the fish only have tilapia, the density is recommended100-200tail/Mu; if a small amount of squid and squid are mixed, the density of tilapia is recommended20-30tail/mu. This model of tilapia can be used to eat sick and dead shrimp, cut off the path of shrimp infection, can also effectively inhibit the occurrence of cyanobacteria, can also improve feed utilization, improve water quality, increase the bottom dissolved oxygen, inhibit Vibrio. However, this model still needs to pay attention to the reasonable control of tilapia density. After all, tilapia will compete for shrimp materials, and net catching is also difficult.
Vannamei-Grass carp multi-polyculture mode
This mode of farming is explored by practitioners of shrimp farmers in the low salinity areas of the estuary such as the Pearl River Delta. In the shrimp pond, a small amount of grass carp is mixed, and the incidence of prawn is small, and the survival rate is high. However, there is no systematic technical solution for stocking structure, water quality control and feeding methods. In the past two years, the grass carp market has recovered, and the optimization of this farming mode is very necessary.
This model stocks 50,000 tails per mu of shrimp, 30-40 per mu of grass carp, a small amount of filter-eating squid and squid, and 20-50 per mu of omnivorous squid. If you don't raise squid, you can change it to 20-30/mu of Egyptian leather beard. The fry are placed in the pond at least 15 days after entering the pond. The culture process does not change the water, and the micro-ecological preparations are regularly placed according to the weather and water quality to regulate the water environment. After the first shrimp is cultivated, if the water temperature is suitable, the shrimp seedlings should be directly placed in the second pond for breeding, and the polyculture fish should be kept in the pond, but the grass fish size should be controlled within 2kg, or the fry should be supplemented according to the ratio of the first one. In addition to water transfer and oxygenation in the breeding process, the grass carp needs to be fed twice a day to feed the puffed feed for domestication. The underwater part of the fence is opened after at least 30 days of domestication.
This model grass carp prey on diseased shrimp, control pathogens; inhibit Vibrio, prevent shrimp disease; increase fish production by more than 400 kg / mu; water quality is better than single-nutrition, reduce medication; in polyculture mode, shrimp income accounts for 60%, fish The income is 40%, and the risk of breeding is low.
Shrimp pond seine separated multi-composite culture
For example, the white shrimp and the scorpion net are separated and mixed. The density of the shrimp is suitable for 50,000/mu, the carp is 100-150/mu, and a small amount of Egyptian leather beard. A large fence is built in the central area of Tuchi, accounting for 1/4~1/3 of the pond area. The aperture of the fence is based on the escape of the carp fry. After the fertilizer is used, the carp species are stocked in the fence and the fish are fed in the fence before the breeding. Feed, no bait in the middle and late stages; if the water temperature is suitable after the first shrimp cultivation, the shrimp ponds will be directly put into the pond, and the fish will be kept in the pond or the fry will be supplemented according to the first ratio. The culture process does not change the water, and the micro-ecological preparations are regularly placed according to the weather and water quality to regulate the water environment. This model is low in cost and easy to handle, and is suitable for omnivorous or filter-feeding varieties such as tilapia, milkfish, and squid.
Shrimp pond seine separated multi-composite breeding map
Zhu Changbo introduced its advantages: in the central area of the pond, the seine does not feed the catfish, does not increase the environmental load of the pond, significantly improves the feed utilization rate, reduces the feed coefficient of the shrimp, improves the pond output efficiency, and reduces the waste. emission.
Rice and shrimp co-production for ecological shrimp farming
Zhu Changbo introduced that this is a new model of shrimp culture. Planting rice in ponds can reduce nitrogen and phosphorus, promote sediment oxidation, lower water temperature in summer, provide concealed areas to improve survival rate, and can be used as farmland base fertilizer after rice straw is crushed. No secondary pollution.
The rice with water-resistant and salt-tolerant varieties was planted in shrimp ponds, and the effects of water stabilization, emission reduction, energy saving and income increase were achieved through the mutual benefit of shrimp and sea rice, Macrobrachium rosenbergii and conventional rice. Zhu Changbo said that the rice ponds are excellent in environment, and the survival rate of shrimps is high and the vitality is strong!
In recent years, vigorously demolition, control, and ban prevention operations have been carried out throughout the country. It is imperative to make changes to the traditional shrimp farming model. The above several farming models have made control on reducing waste emissions. Zhu Changbo suggested that some areas may not have started to rectify now, but changing the traditional farming mode, ecological farming is the trend of the times, and preparing farmers early is the key to ensuring their own interests.