When a fish sanctuary is established it continues as a fish sanctuary until it is directed to be closed by the owner of the land in the case of private property or in the case of public property by a majority of the legislative delegation of the county in which it is located and there may be no fishing or trespassing upon any waters established as a sanctuary. The department may post signs within the sanctuary to identify it as a sanctuary and may prosecute a person fishing or trespassing on the sanctuary.