The Environmental Analysis Logic Method was used to evaluate the inhabitable condition for Haliotis
(Nordotis) disctts hamai at the longshore area in the north part of Miyagi prefecture, Japan.
The suitable conditions were as follows. There is no Dilophus okamurai, and the area is offshore, and the
distance from a sandy bed is more than 10 m, and the stone on a bed is not mobile. The unsuitable conditions
were as follows. There is Dilophus okamurai or the area is inshore, or a sandy bed exists, or the distance from it
is less than 10 m.
In order to improve the unsuitable conditions in some areas, the techniques were proposed such as immobilization of sand or small stone, the removal of Dilophus okamurai, and planting their favorite seaweeds.
It was also indicated that the Environmental Analysis Logic Method was more useful than the multi variate
analysis in that the bioIogical and physical information was taken into account for the evaluation.
The intemal wave is induced in a stratified bay with shallow mouth by tidal waves. If the intemal wave is
considerably amplified, the vertical mixing processes such as the wave breaking on bottom slope, the eddy diffusion
due to intemal shear flow and the sucking out of bottom water to the extemal sea are occurred. In the
present study, hydraulic experiments on intemal wave excitation by a steady surface tide in a simple bay model
were carried out. The generation of intemal waves and the miximg among the lower layer water, the upper layer
water and the extemal water are measured in detail. Modeling the mechanism of the phenomean, three layer
box model is applied.
Five marine ranches which have acoustic sound for red sea bream have been made in the Oita prefectural
sea area since 1986. The four of them are located in the northern part of the Bungo-suido, Usuki and Tsukumi
bay. In this report, We have tried to simulate future management for them with emphasis on the economic effects,
using twelve types of management factors, in term of seed liberation, size regulation, fishing days and their
As a result of this, the net profits for natural and liberated fish in regards to the three types of management
factors were connected mostly with size regulation. The seed liberation factor does not provide enough profit in
itself. To provide economic gains size regulation should be added as a management factor. And, in order to
achieve the manegement aim, a period of five years is necessary after the management system is started.