Development a system for counting marine species in ballast water

Ballast water is used essentially to maintain stability and safety of ships during no shipping. Ballast water is pumped-in to maintain safe operating conditions throughout a voyage. This practice reduces stress on the hull, provides transverse stability, improves propulsion and maneuverability, and compensates for weight lost due to fuel and water consumption. Since all ships are designed for a certain weight range, ballast is used to compensate for unloaded cargo. International Maritime Organization (IMO) estimates that each year about 10 billion tons of ballast water are transported and exchanged around the world during maritime shipping. In this study, we developed a monitoring system to detect living marine species in ballast water. The monitoring system consists of two sub-systems; one is for 10~50 μm species and the other for >50 μm ones, which was designed to be used in situ on ships. The fluorescence due to the chlorophyll and the dyes is used for detecting the 10~50 μm species while the movement of organisms is used for detecting the >50 μm species. The results of this study showed that the developed system to assess the working performance of the ballast water treatment system will be useful in the international commercial ships.