Recently, the shape of fish reef is constructed to create the favorite environmentfor the nekton. Fish reef has the large influence on the flow around it. In this study, weinvestigated the flow pattern around vertical walls which are usually used to constructfish reef.
Separated vortex is generated near the top of vertical wall under the conditionwhere K. C. number is in the range of 0.68 to 2.01. In the case where the interval ofvertical walls is narrower than the diameter of separated vortex and Strouhal number isless than 1.5, significant interaction of the flow between them took place.

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In case of boats mooring in line in marinas and fishing ports, the wind loads against the boats are not equal. It is because the leeward boats are shielded by the windward boats. However, theshielding coefficient of the windward boats and the drag coefficient of boats have never beenstudied befor. Therefore, these coefficients are given by the model tests using the wind tunnel. As a result, the wind load mooring one side of the main pier is larger than the wind loadmooring both sides. And, it became clear that the drag coefficient of these boats isapproximately 0.9 at the side face.

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These days, SFT will be discussed about marine development in several countriesespecially Japan and Norway. In this paper, we researched for the unsteady fluid lift force on SFT caused by vortices and developed flip-flop type actuator for reduction of this unsteadyfluid lift force estimated by measurement of unsteady fluid force and movement of separatingpoints on the surface of SFT used by parameters: St. rotating angle, rotating frequency, andoscillation frequency.

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Recently we have to spread traffic system in the background of expansion ofcommunity to local area. It is useful to develop S. F. T from a view of effectiveusing of ocean space.In this paper, we suggest air spouting type actuator toreduce the unsteady fluid force of S. F. T subjected cross flow.
We researched for unsteady characteristic fluid force of S. F. T and the effectof this actuator by using parameters, void rate, oscillation rate, St. number, oscillaition frequency.

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In this paper, the fluid dynamic stability of the submerged floating tunnel with eliptical crosssectionwas investigated. It was found from fluid dynamic analysis using the discrete vortex methodthat the Strouhal number of this model under the post-supercritical region of Reynolds number is 0.24approximately, and the lift and moment coefficient have a positive gradient. We found from the freevibration analysis that the minimum natural frequency of the structural models is about 7 times ashigh as the vortex shedding frequency. The numerical analysis indicated that the structural modelsare stable for the fluid dynamic vibration.

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The influences of the establishment of coastal structures on local ecology were studied by catching or collecting algae, periphytic creatures, epiphyllous and interfoliaceous biota, and fish in the vicinity of breakwaters and, ascontrol, in sea areas free from influences of such structures.
Biota in areas free from influences of coastal structures were compared with those from in front of breakwaters.Results showed that biota were more diverse among the latter group, with appearance of larger numbers observed ofboth population and species of fish and shellfish, which inhabit algae zones or rocks and conduct feeding andspawning migrations.
Also, the results of comparison between the front and back sides of sloping breakwaters showed that the appearanceof a greater diversity of fish and shellfish was observed at the back sides. Appearance of fry bom from pelagicor periphytic eggs was only observed in the latter case.
From these results, it was confirmed that the coastal structures function as places for fish together. More over, the back side of a permeable sloping breakwater can serve as a place for fish to spawn and fry to grow, due toattenuated wave conditions.

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This Paper introduces, as a case study, the breakwater to be constructed at YOBITO Fishery Harbor in Hokkaido.
The west breakwater is constructed by “Pile Supported Reef”, taking into accountenvironmental condition of habitat conservation, soft ground and tranquility of waterway.

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The authors had tried to apply satellite remote sensing techniques to investigatethe sea water exchange of the Omura and Sasebo Bay. Maximum likelihood method wasused to classify and confirm the exchange condition of sea water bodies. They arenow developing a numerical simulation system which have a three element-controlfunction, and also trying to simulate a tidal current of the Omura Bay by developedsystem. The results of satellite remote sensing are compared with the outcome ofnumerical simulation.

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