1, pond cleaning and disinfestation The function of pond cleaning and disinfestation is to sterilize, eliminate enemy damage, improve the culture environment, effectively prevent the damage of large fierce fish to tilapia, and reduce the competition for feed and water space between wild, miscellaneous fish and fish farming.
2. By cultivating fish with high water quality and large capital turnover, supplemented by fish farming with fat water, the cost can be reduced and risks can be resisted. Before the average body weight of tilapia reaches 0.25 kg, the palatability of basic food organisms can be increased through fertilizer and water, and the breeding cost can be reduced. It is worth noting that all kinds of manure, including livestock manure, green manure and so on. Before being applied to water, it should be disinfected 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. Water quality cultivation in the later stage of aquaculture means that no organic fertilizer can be applied within 3 months before fish are caught, fresh water can be replaced by more water injection in the big water with good water source, and compound microbial agents can be used in the big water with inconvenient water source to remove organic pollutants in aquaculture water, reduce harmful substances such as ammonia nitrogen, hydrogen sulfide and nitrite, stabilize the pH 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. It is best to choose puffed material as feed. Because of the deep water surface, it is difficult for tilapia to eat pellet feed normally if it sinks to the bottom. In order to ensure that the feed is not wasted and easy to observe and manage, it is suggested to choose puffed feed.
3. Breeding high-quality tilapia with high sex ratio is an important link in large-scale aquaculture. If the male rate of tilapia fingerlings is not high, after 4 months of stocking, a large number of tilapia larvae will breed by themselves, and the breeding density will increase rapidly, and a large number of larvae will consume oxygen and substances and seize space. Because it is difficult to dry sugar on the big water, it is usually caught in turn. In actual production, some carnivorous fish (such as raw fish, giant salamander, freshwater pomfret, etc. ) can be released and killed, which can well control the excessive reproduction of the second generation tilapia seedlings. If 100 ~ 300 freshwater pomfrets are stocked, a certain effect can be achieved.
4. Reasonable stocking density should not be too high. Due to the large surface area and difficulty in fishing, it is difficult to completely match the aerobic equipment. Generally, it is not recommended to raise the density too high, and the density should not be higher than 1500/mu. It is an urgent need for aquaculture production to carry out reasonable stocking and greatly improve product specifications. The stocking density of tilapia is 65,438+0,000 ~ 65,438+0,500 fish/mu, freshwater pomfret is 65,438+0,000 ~ 300 fish/mu, silver carp and bighead carp are 50 ~ 80 fish/mu, and grass carp. 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 2 tons, and the product specifications and breeding profits have been improved simultaneously, with an average profit per mu of more than 2,000 yuan.
5. It is very important to harvest scientifically the harvest of large-scale farming. Practice has proved that fish do not eat for 3 days after fishing 1 day, and the food intake is abnormal 1 week. Even if the fish is eaten, the consumption of materials will not increase. Moreover, fishing with nets for a long time is easy to cause fish body damage or even death, and the fish body gradually becomes thinner and devalues. Therefore, it is necessary to catch fish quickly when the time is ripe to 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; The second is to choose a suitable fishing spot, and the place to feed the feed should be set in a place where it is easy to catch fish, so as to ensure that the fish in the fishing area are relatively dense. Shortening Wednesday is to pay attention to market information and strive to harvest in time during the period when the price is better.
The content of this article comes from: The History of Science and Technology Development of Agriculture and Animal Husbandry in Tibet by China Agricultural Publishing House.