Abstract: A method for preventing fouling of an aquatic apparatus by an aquatic organism which comprises affixing a biologically active chemical to a surface intended for use in contact with an aquatic environment containing the organism, wherein the chemical is an enzyme, repellant, chelating agent, enzyme inhibitor, or non-metallic toxicant capable of hindering the attachment of the organism to the surface while affixed to the surface, is disclosed along with improved apparatuses which are produced using the method.

Abstract: Certain furan compounds are disclosed as being useful as marine or fresh water antifoulant compounds to be used in protective carrier compositions such as film forming polymer to protect fish nets, boats, pilings, and piers.

Abstract: Certain gamma lactones are disclosed as being useful as marine or fresh water antifoulant compounds to be used in protective carrier compositions such as film forming polymer to protect fish nets, boats, pilings, and piers.

Abstract: A tissue extract containing a low molecular weight, non-proteinaceous compound selected from the group consisting of (A) methanol-soluble compounds obtainable from Leptogorgia virgulata with R.sub.f values in reverse-phase, thin layer, silica gel chromatography of (1) 0.42, 0.54, and 0.62; (2) 0.35, 0.50, and 0.58; (3) 0.37, 0.47, and 0.58; or (4) 0.31, 0.43, and 0.54, respectively, in 1:1:1 methanol:ethyl acetate:water, 2:1:1 methanol:ethyl acetate:water, and 1:2:1 methanol:ethyl acetate:water, or (B) methanol-soluble compounds obtainable from Renilla reinformis with R.sub.f values in thin layer, silica gel chromatography of (1) 0:44, 0.37, and 0.53; (2) 0.52, 0.42, and 0.60; (3) 0.56, 0.43, and 0.63; or (4) 0.32, 0.26, and 0.37, respectively, in 9:1 chloroform:acetonitrile, 9:1 methylene chloride:acetonitrile, and 4:1 methylene chloride:acetonitrile and compositions containing the same, which is useful as antifouling compositions, is disclosed.