[1] Ancient Roman law set aside res communes omnium (things held in common by all) as not subject to ownership.
The juristic Digest specified things which "by natural law are the common property of all" as air, flowing water, the sea, and the seashore.
Ownership by the Roman people is expressed by publicum and includes human constructs such as marketplaces, harbors, and theatres as well as public lands.
[8] The seashore, defined by the reach of the highest winter tide, was held in common and could not be owned.
At the insistence of English nobles, fishing weirs which obstructed free navigation were to be removed from rivers.
Massachusetts and Maine (which share a common legal heritage) recognize private property ownership to the mean low tide line—but allow public access to the seashore between the low and high tide lines for "fishing, fowling and navigation," traditional rights going back to the Colonial Ordinance of 1647.
In California the situation is more complicated: private landowners often try to block traditional public beach access, which can result in protracted litigation.
The doctrine has been employed to assert public interest in oil resources discovered on tidally influenced lands (Mississippi, California) and has also been used to prevent the private ownership of fish stocks and crustacean beds.
the public trust doctrine has been applied to provide environmental protection to natural resources in order to uphold human rights.