DEVELOPMENT OF PARTICLE TRACKING SIMULATION AND ITS APPLICATION TO COILIA NASUS IN CHIKUGO RIVER ESTUARY

Abstract

 To understand the transport characteristics of particulate biological spices in the estuary environment, a particle tracking module was developed and combined with 3-D hydrodynamic simulator. This methodology was applied to the transport of eggs of Coilia nasus during from spawning to hatch in the Chikugo River Estuary. The egg was modeled to reproduce the effect of buoyancy against ambient water and the tracking path was corrected to avoid trapping by step-like bottom represented by z-coordinate. The effect of buoyancy on the transport distance was investigated by comparing the movements of the modeled particles with those of neutral particles. We found the buoyancy plays an important role in keeping the eggs in the suitable environment for the hatch. The survival rate of the eggs was also estimated in terms of the distance from the river mouth using accumulated salinity value. It was found that predicted location of high survival rate is reasonably corresponding to the location which is pointed out as the spawning location in previous surveys.