Any plats of lands for the cultivation of oysters, clams or mussels held by citizens of this state, if distinctly marked out by means which do not obstruct navigation, and not exceeding the extent allowed by regulations, shall be deemed and protected as private property. Such plats, however, shall not restrict the rights of the public to the use of the waters of this state in a normal and customary manner. [Formerly 509.455; 1997 c.375 § 8]