Flow fields around the artificial fish reef models for three kinds of shapes of a cube, a triangular prism and a quadrangular pyramid have been examined by water- and wind-tunnel testing. Each model shape also has three open area ratios respectively. It is found that there exist the difference in terms of the magnitude and the effective region of the mean velocity deficit due to the variation in the shape of each model. The tendency for the diffussion process of the hydraulic shadow tends to be small for the center plane of z/h = 0, while to be fairly large for the horizontal plane of y/h = 0.5, as the open area ratio of each artificial fish reef model becomes small. Furthermore, the area of the hydraulic shadow is extremely large for the cube and the triangular prism models having small open area ratio, compared with other models with various open area ratios.

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Observation of galvanizing construction of several different hot-dip galvanized steel wires of chain link wire netting being used for floating cage was conducted, and corrosion resistance of galvanizing in these wire nettings under water was investigated mainly using floating cage of wire netting in which culturing yellow tail (Seriola quinqueradiata). As to galvanizing construction on steel wires, in it's up to galvanized with 400g/m² was that the thickness decreasmg rate of Fe-Zn alloy layer in accordance with increasing galvanizing amount was less and the structure was very stable. On the other hand, in steel wires galvanized with over 500 g/m², the alloy layer was extremely thin and the structure was coarse, also proportion of galvanizing thickness on wire surface was shown irregularity. The galvanization corrosion rate of wire netting under water generally observed the greater value than natural corrosion rate in the sea. Steel wires in up to galvanized with 400g/m² proved that when there was more galvanizing amount, galvanization service life more longer. However, this life of steel wire netting in galvanized with over 500g/m² was shorter than that 400g/m². Wire netting superior in corrosion resistance was steel wire's netting of even galvanizing thickness and thin Fe- Zn alloy layer. The galvanizing amount on steel wire for netting to satisfy these conditions was confirmed to be 350 to 400g/m².

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