Institute improves survival rate of young croakers
The West Sea Fisheries Institute of the Academy of Fisheries under the Ministry of Fisheries has put a lot of efforts into developing a technology to artificially propagate croaker, a well-known fish in the West Sea of Korea.
The institute has already succeeded in collecting and hatching tens of thousands of fertilized croaker eggs by discovering a new egg removal technology while artificially quickening the sexual maturity of mother croakers.
“On this basis, we are concentrating on increasing the survival rate of young croakers,” said Choe Ho Yong, director of the institute.
What is important here is the nourishment of young croakers in the period of growing from fry to young fish and from young fish to 12-day ones, he said. If it fails, their survival rate falls.
It is necessary to feed them early attachment food in the stage of fry and enriched food in the period of young fish. To this end, the institute also directs efforts to multiplying unicellular algae and rotifers and providing adequate nutrition.
It also made an assorted feed with high digestibility by rationally mixing various vegetable and animal feeds and all kinds of vitamins.
At the same time, it pays attention to the provision of favourable living environment for the fries.
The researchers have found out the optimum ecological conditions suitable for the growth of young croakers including water temperature, pH and dissolved oxygen and are changing the water of and sterilizing the fish breeding ponds and feeding scientifically.
As a result, the survival rate of young croakers has risen up to over 98 percent.
“Croaker is a sea fish that migrates to the seas of our country in midsummer. We have now undertaken a research project for croaker farming in freshwater to provide people with the rare fish of croaker in winter,” said Choe.
THE PYONGYANG TIMES