海産付着珪藻Nitzschia sp.の増殖に対する酸化マグネシウム混合ポリエチレン被覆鋼線の影響

カキ養殖筏には多くの生物が付着し，中でもろ過摂食者は餌の摂取という点でカキと競合関係にあるため，カキの成長を阻害する要因の1つである。そこで，この研究では，カキ養殖に使われる針金について，生物付着の少ない素材を開発することを目的とし，従来の亜鉛メッキ鋼線に加え，アイオノマー・レジン（ポリエチレン）被覆鋼線，酸化マグネシウム（HUSR）混合ポリエチレン被膜鋼線（HUS混合率3％および5％）を用い，沿岸域に一般的な付着珪藻種Nitzschia sp.の増殖に対する影響を実験的に測定した。その結果，（1）ポリエチレン自体はNitzschia sp.の増殖を阻害しないが，亜鉛メッキ鋼線およびHUS混合ポリエチレン被覆鋼線はNitzschia sp.の増殖を阻害する，また（2）HUSR混合ポリエチレン被膜鋼線では，HUS混合率が高いほどNitzschia sp.の増殖阻害程度は強い，ということが明らかとなった。

Many organisms attached on suspended oyster culture rafts, particularly filter-feeding animals can prevent growth of culturing oyster, because they are competing feeds with oyster in the same niche. In the present study, effects of steel wires coated with various materials on growth of the ubiquitous attached diatom Nitzschia sp. were experimentally examined to develop a better steel wire in terms of less attached organisms. The wire used were a normal zinc-galvanized steel wire, a polyethylene (ionomer resin)-coated steel wire, and magnesium oxide (HUS®)-added (3% and 5%) polyethylene coated steel wires. Following results were obtained, (1) all wires coated with different materials except the ionomer resin itself (as coating material) suppressed the growth of Nitzschia sp., and (2) 5% HUS®-added polyethylene-coated steel wire suppressed the growth of Nitzschia sp. greater than 3% added one did.