The present invention relates to a barnacle attachment stage larvae that includes light having a wavelength range of 409 to 412 nm and including a part of the wavelength range of 400 to 460 nm from the attachment to the attachment stage larvae. Provided is a method for suppressing the adhesion stage larvae of barnacles from adhering to deposits in water by irradiating them. 本発明は、フジツボ類の付着期幼生に対し、４０９～４１２ｎｍの波長全域を含み、４００～４６０ｎｍの波長域のうち一部の波長を含む光を、前記付着物から前記付着期幼生の方向に向けて照射することにより、フジツボ類の付着期幼生が水中で付着物に付着することを抑制する方法を提供する。
