Prevention effect of LED blue light irradiation on the settlement of cyprids

We applied blue LEDs to the prevention of the settlement of cyprids. The relatively strong intensity of the irradiation of ca. 500 (W m
^-2
) could prevent the settlement of cyprids on the area of the bottom of a tub, above which the light source was adjusted. On the other hand, cyprids settled on the area on which the relatively weak intensity of the irradiation, <; 100 (W m
^-2
), was reached. In the field experiments, however, the number of cyprids settled on the adhesion plate, on which the relatively weak irradiation of blue light was reached from the relatively strong light source located 40 cm far from the adhesion plate, was reduced. Moreover, the surface of the transparent acrylic plate used for the LEDs cover was prevented from biofouling in the field. These results indicate that the relatively strong intensity of irradiation of blue light is actually useful for the prevention of biofouling on a ship's bottom.