Analysis of Causes of Death of First- and Last-in-age Grass Carp
1. One-year-old grass carp has gluttony. Snatching food, eating large amounts, and growing fast can easily lead to the formation of a “bubblehead†advantage, but at the same time it is in conflict with its ability to digest and absorb. Therefore, overfeeding often results in dyspepsia and death from morbidity.
2. The water temperature is high and the breeding environment is deteriorating. The first-year grass carp is during the summer season, and the water temperature is usually above 30°C. At this time, the water body is not only high in fatness, but also has low dissolved oxygen in the “fertilizer waterâ€. Moreover, the feeding of feed is highly susceptible to deterioration, which deteriorates the aquaculture environment and causes the breeding of fish diseases. .
3, feeding and management to relax, improper measures. First, excessive watering of grasses, lack of or improper use of high-quality natural feeds such as alfalfa, duckweed, leeches, etc., resulting in malnutrition, weak constitution, reduced immunity and anti-disease ability of fish, and secondly, there is no attention to frequent changes. Water and timely ponds, the density of fish species is too high, the water body is aging, and the water quality is not improved.
Second, key measures to improve the survival rate of first-year grass carp
1, pond clearing. Excavate excess silt (remaining 10-15 cm), thoroughly clear the pond with quick lime, the amount of 75 ~ 100 kg / acre.
2, reasonable stocking. The first is to choose the water body Cladocera breeding peak to release grass carp summer flowers. Generally, the amount of fertilizer is 200-300 kg/mu. 7 to 10 days of culm horns reach the peak; the second is a small amount of squid summer flowers, which mainly serve as feeding baits, detrimental benthic organisms, and limiting food intake. Usually 1,000 grass carp summer flowers are raised 200 to 300 fish.
3, to ensure the supply of high-quality natural food. The bait is mainly based on Cladocera, Euphorbia, duckweed, etc., and fine materials should be used properly.
4, change the feeding method to avoid the formation of "bubble". One is to appropriately increase the number of bait stations and require that at least one of the 5,000 fish species should be set up; second, the feeding should be uniform to avoid undue delay; and third, fish diseases must be properly restricted during the season.
5, to ensure fresh water. One is to flush water in a timely manner, each time 5 to 10 centimeters, especially in the hot season 1 to 2 days to flush once; the second is to promptly remove dead fish and uneaten residual grass and debris.
6, timely pull the net, the "bubble" screen out, pool or adult fish pond farming.
7, pay attention to fish disease prevention and treatment. First, the use of grass pulp hemorrhagic tissue pulp Inactivated Vaccine soaked or injected; Second, every 10 to 15 days of fish disease season with 20-30 kg per acre of limestone Quanchiposa; Third, every half a month with garlic head Rotten fish fed with 100 grams of garlic with 1000 grams of mixed bait, each feeding 3 to 4 days, respectively, to control the grass carp bleeding, rotten carp and enteritis disease.
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