Nippon Suisan Gakkaishi 75 (6), 1051-1060 (2009)

Suitable substrate for thalli attachment of the agar alga Gelidium elegans (Gelidiales, Rhodophyta)

MIHO TSUCHIYA,1 KENJI TAKIO,2 KAZOTO ANDO,2a
KATSUTOSHI KAWABE,2b ICHIRO KOMAZAWA2a AND HISAYUKI ARAKAWA1*

1Department of Ocean Sciences, Tokyo University of Marine Science and Technology, Minato, Tokyo 108-8477, 2Oshima Branch, Tokyo Metropolitan Islands Area Research and Development Center of Agriculture, Forestry and Fisheries, Oshima, Tokyo 100-0212, Japan

After the volcanic eruption in 2000, the quantity of agar alga Gelidium elegans remarkably decreased in Miyakeshima Island, and so efforts to increase the production are necessary. We identified a suitable substrate to enhance thalli attachment of agar alga and examined its properties.

   (1) We set artificial reefs with substrates of mortar blocks, steel fence, stainless steel bolts, and stainless steel bolts covered with chemical fiber fabric on the bottom of the fishing port of Oshima and observed the attachment, adhesion, and growth of thalli of G. elegans on each substrate. Many thalli of G. elegans attached rapidly to the perpendicular substrate of stainless steel bolts with the chemical fiber fabric. After one year this substrate was mainly covered with G. elegans. (2) In the laboratory we examined the change of density of attached thalli on the above four kinds of substrate and also tested five kinds of chemical fiber. Density of attachment and residual ratio of the thalli were the highest on the substrate with chemical fiber fabric. (3) It is considered that the attachment of the thalli is related to the number and curve ratio of prominent fibers in the chemical fiber string.


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