A coating composition comprising a) seawater-hydrolyzable groups covalently linked to a polymer backbone, which seawater-hydrolyzable groups are capable of undergoing hydrolysis or ion-exchange when exposed to seawater, rendering the polymer partially soluble or dispersible in seawater, and b) zwitterionic groups covalently linked to a polymer backbone wherein the polymer backbones to which the sea-water-hydrolyzable groups and the zwitterionic groups are attached serve as a film-forming binder in the coating composition and is an acrylic polymer, and wherein the molar ratio of the seawater-hydrolyzable groups a) to the zwitterionic groups b) is 0.1 or higher, wherein the seawater hydrolyzable groups are selected from: the group consisting of non-metal salt groups, metal salt groups, silyl ester groups, and mixtures thereof, wherein the non-metal salt groups covalently linked to the acrylic polymer are obtainable by: using cationic, non-metal salt group containing monomers selected from the group consisting of quaternary and acid salts of dialkylaminoalkyl(meth)acrylates, quaternary and acid salts of dialkylaminoalkyl(meth)acrylamides, N,N-diallyldialkyl ammonium halide, (3-methacryloylamido)propyl trimethylammonium halide salt; (3-acryloylamido)propyl trimethylammonium halide salt; (3-methacryloylamido)propyl trimethylammonium sulfonate salt, (3-acryloylamido)propyl trimethylammonium sulfonate salt, (3-methacryloyl)propyl trimethylammonium sulfonate salt, (3-acryloyl)propyl trimethylammonium sulfonate salt; or by using anionic, non-metal salt group containing monomers selected from the group consisting of amine and phosphine salts of polymerizable unsaturated carboxylic and sulphonic acids wherein the silyl ester groups covalently linked to the acrylic polymer are obtainable by using silyl ester group containing monomers selected from the group consisting of triisopropylsilyl (meth)acrylate, triisobutylsilyl (meth)acrylate, triphenylsilyl (meth)acrylate, and t-butyldiphenylsilyl (meth)acrylate. a) seawater-hydrolyzable groups covalently linked to a polymer backbone, which seawater-hydrolyzable groups are capable of undergoing hydrolysis or ion-exchange when exposed to seawater, rendering the polymer partially soluble or dispersible in seawater, and b) zwitterionic groups covalently linked to a polymer backbone the group consisting of non-metal salt groups, metal salt groups, silyl ester groups, and mixtures thereof, wherein the non-metal salt groups covalently linked to the acrylic polymer are obtainable by: using cationic, non-metal salt group containing monomers selected from the group consisting of quaternary and acid salts of dialkylaminoalkyl(meth)acrylates, quaternary and acid salts of dialkylaminoalkyl(meth)acrylamides, N,N-diallyldialkyl ammonium halide, (3-methacryloylamido)propyl trimethylammonium halide salt; (3-acryloylamido)propyl trimethylammonium halide salt; (3-methacryloylamido)propyl trimethylammonium sulfonate salt, (3-acryloylamido)propyl trimethylammonium sulfonate salt, (3-methacryloyl)propyl trimethylammonium sulfonate salt, (3-acryloyl)propyl trimethylammonium sulfonate salt; or by using anionic, non-metal salt group containing monomers selected from the group consisting of amine and phosphine salts of polymerizable unsaturated carboxylic and sulphonic acids wherein the silyl ester groups covalently linked to the acrylic polymer are obtainable by using silyl ester group containing monomers selected from the group consisting of triisopropylsilyl (meth)acrylate, triisobutylsilyl (meth)acrylate, triphenylsilyl (meth)acrylate, and t-butyldiphenylsilyl (meth)acrylate. using cationic, non-metal salt group containing monomers selected from the group consisting of quaternary and acid salts of dialkylaminoalkyl(meth)acrylates, quaternary and acid salts of dialkylaminoalkyl(meth)acrylamides, N,N-diallyldialkyl ammonium halide, (3-methacryloylamido)propyl trimethylammonium halide salt; (3-acryloylamido)propyl trimethylammonium halide salt; (3-methacryloylamido)propyl trimethylammonium sulfonate salt, (3-acryloylamido)propyl trimethylammonium sulfonate salt, (3-methacryloyl)propyl trimethylammonium sulfonate salt, (3-acryloyl)propyl trimethylammonium sulfonate salt; or by using anionic, non-metal salt group containing monomers selected from the group consisting of amine and phosphine salts of polymerizable unsaturated carboxylic and sulphonic acids wherein the silyl ester groups covalently linked to the acrylic polymer are obtainable by using silyl ester group containing monomers selected from the group consisting of triisopropylsilyl (meth)acrylate, triisobutylsilyl (meth)acrylate, triphenylsilyl (meth)acrylate, and t-butyldiphenylsilyl (meth)acrylate.