センスイ カンサツ ニヨル ジンコウ ギョショウ ノ ジッタイ ニツイテ XVI : サツマハントウ カイモンチョウ オキアイ カイイキ ノ バアイ

During the periods from the 27th of September in 1984 to August in the same year, and on the 23rd of July in 1985, diving observations were carried out on the artificial concrete block reefs submerged at the off sea of Kaimon Town situated at the southern end of Kagoshima Prefecture, with the following informations obtained. (1) Concerning the reef-group submerged at the sea-front lying East of Kaimon mountain, it was ascertained that the depth at which the group was set-in showing 35~60m, the shape being two-headed-hill type. The setting-in was made quite well, making full use of the topography of the sea-bottom, which gave good fish gathering effect on to the group ; and the reef-group gathered a lot of useful fish, such as Sea pike Sphyraena schlegeli Saurel Trachurus japonicus Striped sea perch Lutjanus vitta and Thick lip bream Plectorhynchus pictus. And the reef-group was noted to be playing a part as a sort of fish-leading reef added to the fishing ground of the Set Net. (2) On the other hand, in case of the reef-group submerged at the sea-front lying West of the Kaimon mountain, the reefs were set in a scattering condition, separated by a wide distance between the individual reefs. Adding to this, the reefs near the seashore were to be influenced by the waves, and were apt to be buried with sand and mud ; as a matter of fact not a small number of them were wholly buried. To prevent them from being buried some of the reefs were set-in over the sea bottom covered with the preliminarily submerged small stones. However, the widely scattered reefs were incapable of getting a good fish-gathering effect.昭和59年9月27日より10月1日にかけ,また昭和60年7月23日,鹿児島県薩摩半島南端の開聞町沖合海域に設置されている6個所の人工魚礁について潜水観察を実施し,下記のような知見を得た。(1) 開聞岳の東方海域の魚礁群は,設置水深が35~60mと深く,また形態は2山型をなしている。海底地形を巧みに利用しているため,カマス,マアジ,ヨコスジフエダイ,コロダイ等の有用魚を多く集めており,定置漁場の誘導魚礁的役割を果たしている。(2) 開聞岳の西方海域の魚礁群は,個体間隔の広い分散型に設置されている。沿岸に近い魚礁は,波浪の影響を強く受けるので,埋没し易く,魚礁の中にはほとんど埋没したものも多く認められた。埋没を防止するため,海底に敷きつめた丸石群の上にコンクリートブロックを設置した魚礁もあるが,広範囲に分散しているためか蝟集魚は貧相であった