Abstract
Seawater exchange and mixing between the inner and outer side of a bay are important factors controlling
its marine environment and productivity. Studies on the hydraulics of stratified culture grounds are very few, and
many things still remain unknown.
A study on seawater exchange due to intemal tide and intrusion of density front has been carried out on the
basis of observed oceanographical conditions from yellowtail culture grounds in Nomi Bay and the scallop culture
farm at Lake Saroma in the season when stratification occurs. Moreover, a density current ditch method that can
promote the seawater exchange of fishing ground utilizing density current has been proposed. Its effectiveness
was examined using a hydraulic model experiment.
