This is called the public trust doctrine. Also see Illinois Central Railroad Co. v. Illinois. Its the same here in Connecticut and I take advantage of it.

http://www.ct.gov/deep/cwp/view.asp?A=2705&Q=323792

Connecticut's shore belongs to the people--not just in terms of our environmental and cultural heritage, but in a specific legal sense as well. Under the common law public trust doctrine, a body of law dating back to Roman times, all coastal states as sovereigns hold the submerged lands and waters waterward of the mean high water line in trust for the public. The general public may freely use these lands and waters, whether they are beach, rocky shore, or open water, for traditional public trust uses such as fishing, shellfishing, boating, sunbathing, or simply walking along the beach. In Connecticut, a line of state Supreme Court cases dating back to the earliest days of the republic confirm that private ownership ends at mean high water line, and that the state holds title to the lands waterward of mean high water, subject to the private rights of littoral or riparian access.

The public trust area comprises submerged lands and waters waterward of the mean high water line in tidal coastal, or navigable waters of the state of Connecticut. On the ground, the public trust area extends from the water up to a prominent wrack line, debris line, or water mark. In general, if an area is regularly wet by the tides, you are probably safe to assume that it is in the public trust. The public trust area is also sometimes referred to as tidelands, and is defined as "public beach" by the Connecticut Coastal Management Act, C.G.S. 22a-93(6).

"Public rights include fishing, boating, hunting, bathing, taking shellfish, gathering seaweed, cutting sedge, and of passing and repassing. . ." Orange v. Resnick, 94 Conn. 573 (1920).

"It is settled in Connecticut that the public has the right to boat, hunt, and fish on the navigable waters of the state." State v. Brennan, 3 Conn. Cir. 413 (1965). The public has the right to fish and shellfish over submerged private lands, Peck v. Lockwood, 5 Day 22 (1811).

The public has the right to pass and repass in navigable rivers, Adams v. Pease 2 Conn. 481 (1818) .

The public may gather seaweed between ordinary high water and low water, Chapman v. Kimball 9 Day 38 (1831).

In almost every case, private property ends, and public trust property begins, at the mean high water line (often referred to as "high water mark" in court decisions). Mean high water is the average of high tides over a defined period, and its elevation can be obtained from standard references, including the U.S. Army Corps of Engineers Tidal Flood Profile charts.

The public owns up to "high water mark," Simons v. French, 25 Conn. 346 (1856).

Title of riparian proprietor terminates at ordinary high water mark, Mather v. Chapman, 40 Conn. 382 (1873).

"High water mark" = "mean high water mark" = "ordinary high water mark." Private ownership of submerged lands is possible, only when basins are dredged from upland, or from inland, non-navigable waters. Michalczo v. Woodmont, 175 Conn. 535 (1978).

The adjacent landowner has the exclusive riparian or littoral right of access to navigable water. This does not mean that the owner can exclude others from the adjacent waters, but that only the owner may get to the water from his or her upland, as by constructing a dock or other structures where appropriate and appropriately authorized. In terms of access, navigable waters are equivalent to a public road, and a dock serves the same purpose as a private driveway. A littoral landowner may not exclude the public from lawful uses of the public trust area, just as an upland owner cannot exclude the public from driving or walking on the street in front of his or her house. Of course, nuisance behavior in the public trust, such as littering, intoxication, etc. would constitute a breach of the peace, just as if done by neighbors on adjacent upland property.