A protective layer which prevents marine fouling when attached to a boat hull or other structure intended to be submerged underwater. The protective layer achieves its anti-fouling characteristic by incorporating anti-fouling compounds uniformly dispersed throughout either a plastic film or an adhesive used to bond the film to a surface to be protected which slowly leach into the surrounding marine environment. The film is removably adhered to a boat hull or other structure by a thermally sensitive thermoplastic adhesive. The film may be removed by simply reheating until the adhesive softens to thereby allow the film and any undesired marine organisms attached thereon to be peeled away from the boat hull.