present invention, as marine antifouling agents, as compared to dexmedetomidine, relatively more of the multimers Rebomedetomijin, or the use of medetomidine containing salt or solvate thereof. Furthermore, the present invention provides a surface coating composition comprising such medetomidine, surface coated with such a medetomidine, and a method of preventing marine biofouling using such medetomidineFIELD 2