"On the surface of the water, there are shrimp fry everywhere, flocks of shrimp fry, jumping around..." Recently, at the Yingxiang Village Aquaculture Farm in Maqiao Town, Jingjiang City, Taizhou, Jiangsu Province, Zhao Yuanxin, the director of the farm, is leading the villagers to catch the last batch of green shrimp fry this year and sell them to neighboring farms.
Yingxiang Village Aquaculture Farm covers an area of more than 200 mu, and is one of the demonstration bases for the promotion of Modern Agriculture (Green Shrimp) Industrial Technology System in Taizhou in Jiangsu Province. Under the guidance of taizhou Academy of Agricultural Sciences, the aquaculture farm has taken the lead in experimenting with the new technology of "ectopic artificial breeding of zooplankton" green shrimp seedlings in Proud and Jiangsu Province since last year, producing about 90 kg of shrimp fry per mu, increasing the yield by about 30%, and increasing the benefit by about 2500 yuan per mu. At present, the Taizhou Academy of Agricultural Sciences has declared the new technology of green shrimp seedlings for the national invention patent.
Nursery is an important part of the shrimp farming industry. The farmed species in Taizhou City are mainly "Taihu No. 2" green shrimp, which were generally transferred from other places in the past, while shrimp fry have high oxygen demand, are not tolerant of long-distance transportation, and have a low survival rate. Yingxiang Village Aquaculture Farm adopts the self-propagating method to cultivate shrimp fry, in addition to supplying the village farm, at the same time supplying seedlings to surrounding farmers, to solve the problem of insufficient supply of local shrimp fry in Taizhou.
The shrimp fry breeding base of Yingxiang Village Aquaculture Farm has 7 ponds, a total of more than 60 acres. Among them, The area of No. 7 Pond Mouth is the smallest, only about 1 acre. This pond mouth is different from the nursery pond, which does not contain shrimp fry, but is specifically used for the cultivation of zooplankton, called zooplankton breeding pond, which is the core part of the nursery technology.
Shrimp fry grow from arthropods to the larvae of bran shrimp are mainly suspended in the upper layer of the water body, and 8 to 9 molting needs to be carried out, and the need for water nutrition at this stage is more urgent, especially the need for calcium. Zhao Yuanxin said that shrimp fry are mainly based on zooplankton, if there is a shortage of natural zooplankton at the mouth of the pond, they will go to the zooplankton breeding pond to catch zooplankton and other zooplankton, as shrimp fry bait fed to the pond mouth, improve the survival rate and growth rate of bran shrimp larvae.
Ectopic artificial breeding, that is, to re-select the breeding pond, not to cultivate zooplankton at the mouth of the original farmed shrimp fry pond, although the breeding area is increased, but the breeding efficiency is improved. Yang Zhijing, assistant researcher of the Characteristic Aquatic Products Research Office of Taizhou Academy of Agricultural Sciences, conducted research at the scene to check the growth of shrimp fry. Yang Zhijing said that 1 mu of nursery pond only needs to be equipped with about 5 square meters of zooplankton breeding pond, and the increase in breeding area is less than 1%. In addition, with this new technology, 1 kg of egg-hugging shrimp can produce 100,000 to 120,000 shrimp fry, an increase of 20 to 30%, and the size is larger.
"Organic fertilizers are indispensable for the cultivation of zooplankton, and the oxygen consumption of this process is large, which can easily lead to the increase of ammonia nitrogen and nitrite in water." Yang Zhijing said that through ectopic artificial cultivation, there is less interference with the aquaculture water body, and the farmers can easily control the water quality of the aquaculture water body. If there is a surplus of zooplankton, it will consume a large number of phytoplankton, resulting in an imbalance in the algal phase, and even the need to control the number of zooplankton with insecticides and affect water quality. Ectopic artificial cultivation is more similar to feeding bait and is easy to control and manage.
At present, Taizhou City has promoted the new technology of "ectopic artificial breeding of zooplankton" green shrimp seedlings in Xinghua, Jiangyan, Jingjiang and other places, with a seedling area of 1,000 mu. Due to the good quality of the seedlings, local and Yangzhou, Yancheng and other surrounding areas of the farmers have come to buy shrimp fry, the application and promotion area accumulated more than 10,000 acres.