No signs, fences or entreaties can keep these vandals away from the sprawling waterfront park at the foot of the Brooklyn Bridge.

They relentlessly attack the timber pilings that hold up the pristine lawns, basketball and handball courts, soccer and lacrosse fields, and roller skating rink, and threaten the future of an 85-acre park that has become a showcase for New York’s waterfront redevelopment.

They are marine borers — so named because they leave behind wood riddled with holes.

Along with oysters and other marine life, these pests have come roaring back to New York Harbor, threatening almost anything in the water made of wood.

They are the beneficiaries of more than four decades of federally mandated efforts to clean up the industrial pollutants and raw sewage that had turned the harbor into a marine wasteland.