Abstract: The Weitou Bay, with wide mouth open to the Taiwan Strait, is located in the middle of Fujian Province.From March 2004 to February 2005, the netting test panels, which were made of blacknetting of PA210D/26×3-60 fixed on rigid frame of 50 cm, were laid down in the open ocean cageaquaculture area of the Weitou Bay in order to examine the set tlement and stat us of fouling organisms.154 species were recorded with the dominants of Ceramium tennuissmun, Tubularia mesembry anthemum, Caprella equilibra in spring and Balanusreti culates in summer.The monthly average biomass of fouling organisms was 449.42 g/m² in the depth of 1 m and 580.25 g/m² in 4.5 m, and the highest amount appeared in April and March respectively.The seasonal average biomass was 3 142.30 g/m² in the depth of 1 m and 6 030.97 g/m² in 4.5m, and the highest amount occurred in spr ing and summer respectively.The fouling organisms in open ocean cagearea occurr ed throug hout the year but is much different from the inner bay, where the biomass of Ceramium tennuissmun, Tubularia mesembry anthemum, Caprella equilibra and Balanus were much smaller than that in the open ocean cage culture area.