It shall be unlawful, except as provided herein, for any person to trespass upon or attach a boat or other device to any privately owned dock erected along the shores of any public or private waters within this State. Provided, however, that no person shall be convicted under this chapter unless the owner of such dock has posted a notice in a conspicuous place thereon stating that "Trespassing on this Dock is Prohibited by Law." Any person violating the provisions of this chapter shall be deemed guilty of a misdemeanor and upon conviction shall be fined not less than twenty-five dollars nor more than one hundred dollars.