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2 非会員 宇部工業高等専門学校 物質工学科(〒755-8555 山口県宇部市常盤台2-14-1) 3 正会員 復建調査設計株式会社(〒732-0052 広島市東区光町ニ丁目10-11) 4 正会員 放送大学(〒261-8586 千葉市美浜区若葉2-11) 本研究は，岩礁性藻場に隣接して創出した岩礁性藻場生育基盤に着生した海藻の種類や量，生息する動 物の量の違いについて長期的なモニタリングをすることで，創出を隣接させることや創出規模の効果につ いて検証することを目的とした．第1期，第3期及び第4期への海藻着生量はそれぞれ創出後40ヶ月，19ヶ 月及び16ヶ月程度まで増加した．周辺天然藻場に着生した海藻との類似度指数が概ね0.70を超えたのが， 第1期，第3期及び第4期ではそれぞれ73ヶ月，38ヶ月及び22ヶ月と隣接して藻場生育基盤を創出するたび に，周辺天然藻場の海藻種に近づく期間が短くなった．岩礁性藻場生育基盤の創出後の経過時間及び創出 規模と付着生物量及び魚類出現密度との間に関係は確認できなかった．岩礁性藻場生育基盤の創出を隣接 させ，創出規模が大きくなるたびに海藻の種類数や着生量が増える期間や周辺天然藻場に類似度が近づく 期間が短くなった．

To clarify capability of small scale artificial tidal flat (SAT) in urban area, we focused on manila clam production and investigated some SATs in Tokyo Bay. Manila clam production rate on a main SAT was comparable or higher than natural tidal flat in Tokyo Bay. But, manila clam was damaged by hypoxia seriously in late summer to autumn in one SAT which was main research area. Another one SAT, manila clam wasn't damaged hypoxia, because of the shallow area was widely than main SAT. Further, benthic microalgae was main food source of Manila clam in all SATs, and manila clam populations related to benthic microalgae abundance. It suggested manila clam production was affected directly benthic microalgae production, and benthic microalgae production on SAT was changed by design or maintenance condition of each SAT.

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The objective of this study is evaluate algal bed substratum by steel-making slag. We carried out construction of algal bed substratum by steel-making slag that of particle size finer than natural rock. When algal bed substratum was constructed, the value of the turbidity and pH was almost the same as the surrounding sea area. It could not be confirmed increase in pH when steel-making slag was submerged into the sea. The steel-making slag had been maintained as algal bed substratum after one year. The algal species and amount of the constructed bed by steelmaking slag has been similar that of natural bed and constructed by natural rock.