Abstracts: Acorn barnacles are common marine invertebrates with pelagic and benthic stages in their lives. The barnacle Amphibalanus reticulatus is usually a key species in the fouling communities of tropical and subtropical waters and plays an important role in marine ecosystems. Further exploration of the relationship between its larval settlement and different physicochemical factors is of importantly theoretical and practical significance. In this study, egg lamellae obtained by dissecting field-collected adults of A. reticulatus were placed in filtered seawater. The hatched nauplii were reared at 30 ℃ in darkness with the alga, Platymonas subcordiformis, at a concentration of 2.5—3.0 ?105 cells/mL. Plenty of cyprids were present after 5 days. They were collected and stored at 4 ℃ for the following tests. The effects of five organic compounds (dose of 10 μg/cm2), including diuron, zineb, triclosan, 3-sulfopropyl methacrylate potassium salt (SPMA) and sulfobetaine methacrylate (SBMA), on the cyprids were studied. Then cyprid settlement on 5 different substrata — glass, paraffin wax, agar gel, polystyrene plastic and stainless steel was observed. All experiments lasted for 120 hours and both surviving and settled individuals were counted at intervals every 24 hours during the study period. And the shear attachment strength of barnacles on the stainless steel panels immersed in the sea for 3 months was measured and analysed. The results indicated that after 120 hours the larval settlement rates in the diuron, zineb and triclosan treatment groups were 27.8%, 32.6% and 49.8%, respectively, and significantly less than the control group (74.8%) (P<0.05). However, in the monomeric SPMA and SBMA groups, the settlement rates were 70.9% and 72.2%, respectively, and there were no significant differences compared with the control (P>0.05). As for the larval survival rates, there were no significant differences among the 5 organic compounds and control groups (P>0.05). Concerning the impact of substrata, there were no significant differences in the settlement rates on glass, paraffin wax, polystyrene plastic, and stainless steel. However, the settlement on agar gel was 11.0% and 32.1% at the 24 hours and 48 hours, significantly less than the other 4 groups (P<0.05). After 72 hours, more larvae settled on the agar gel and no difference, compared with the other groups, occurred during the subsequent period. Regarding the adhesion of barnacles on the stainless steel panels, data on the shear stress were within the range of 0.18 MPa to 0.38 Mpa, with the average value being 0.31 Mpa. Although the shear force required to peel off barnacles became greater with growth (i.e. the baseplate area expanding), the increase in shear attachment stress was not significant. In conclusion, at the dosage of 10 μg/cm2, diuron, zineb and triclosan could inhibit the larval settlement of A. reticulatus, but not affect cyprid survival. Less larvae settled on the agar gel within the initial 48 hours, and then the difference in larval settlement rates no longer existed among the 5 substrata mentioned above through time. The shear adhesion stress of the barnacle Balanus reticulatus colonizing stainless steel panels did not change significantly with growth presenting a relatively stable state. The study can provide a scientific basis for the development of research on marine antifouling strategies and ecological environmental protection.