The effect of the low apparent solid surface energy of a specially engineered substrate on the settlement of barnacles was studied. To obtain an aluminum (Al) plate with low apparent solid surface energy, a plate was roughened by sandblasting and electrolytic chemical etching, and then coated with a chemically adsorbed monolayer (CAM) containing a fluorocarbon group. The plate was characterized by means of fluid contact angle measurements and a barnacle settlement test. The water contact angle (WCA) was 152°, and the oil contact angle of n-hexadecane (OCA) was 121°. The surface of the plate thus displayed super-hydrophobicity and high-oleophobicity. In addition, the wettability of this surface was evaluated, in terms of calculated apparent total solid surface energy, as approximately 1.6 mN/m. In laboratory experiments, barnacles did not settle on the plate when exposed for 7 days. In comparison to controls using a variety of untreated and partially treated plates, this indicates that the surface treated to have low apparent solid surface energy can have an anti-biofouling effect, which may be explained by a combination of effects of relief and material.

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Some topics were reviewed from recent advances in the biology of alien ascidians, with special reference to the taxonomy, phylogeography and embryology (in terms of the artificial crossing and the time of natural spawning) of Ciona intestinalis species complex Sp. A to D, and the taxonomy of C. savignyi, including a short historical retrospect on the discovery of the latter species' taxonomic identity. Brief references were also made to the recent invasion of Ascidiella aspersa to the Japanese waters, the taxonomy and ecology of the notorious “D-vex”, Didemnum vexillum (once misidentified as D. pardum in Japan), the phylogeography of Styela plicata as so far unsuccessful trials to reveal its native range of geographical distribution, and that of S. clava.

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