STUDY ON THE CONDITIONS OF MAKING HABITATS OF SEEDING

Abstract

This study examined the conditions in order to make most suitable habitats for hatchery-reared Japanese flounder. Flounder's critical velocity of bottom-clinging was estimated almost the same the swimming velocity under steady flow, which was about the four or six times of its total body length (TL). The value of the coefficient of flow tolerance took from 0.2 to 03, and the coefficient of mass force did about 1.0. On the basis of that result, the relationship between the thrust (Ft: dyn) and TL was closely resembled as Ft=15.2×TL2.73, and the wave conditions (Hmax: a maximum allowance wave Height) allowed to be suited for making habitats of flounder, a wave period (T: second), and the depth of liberation area (h: m) was described as Hmax=23.02T-1.36TL0.97h based on the theory of micro amplitude. Further more, the maximum burrowing depth observed the tendency of gradual decrease with its body length's increase. In this experiment, no population was observed washed away in spite of the hard drift sand conditions.