Press Release

May 28, 2012

Incorporated Administrative Agency, Fisheries Research Agency

Continuous and closed-circulating rotifer culture system developed!
Achieving zero environmental impact and reduced costs

  • Wastewater from rotifer culture can be reduced from 20-120 thousand liters per 30 days to zero

Rotifers (Brachionus plicatilis sp. complex) are indispensable in the production of fish seeds as they are used to feed early-stage fry. Conventional mass production methods of rotifers produce a large amount of wastewater, which contains organic matter such as excrement and the remains of rotifers, and requires additional costs for building and running wastewater treatment facilities.

The Japan Sea National Fisheries Institute of the Fisheries Research Agency has designed a continuous and closed-circulating system for culturing rotifers. The system is installed with a device for filtering and recirculating waste culture water and can stably produce high-quality rotifers over a long time. The structure of the filter tank was especially improved to increase the wastewater processing.

The Institute produced about 4 billion rotifers (enough to feed 400 thousand flounders) stably and continuously by using the system over a period of 30 days without adding any seawater. The system can produce a large number of rotifers at reduced cost in an environment-friendly manner, reducing the wastewater from 20-120 thousand liters to zero.

Cultures of rotifers are being further tested to investigate appropriate culture conditions, control methods, and rotifer species aiming to further improve and spread the system to actual fields of fish seed production.