Section 13. There are hereby established the following ocean sanctuaries:

(a) The Cape Cod Ocean Sanctuary is described as follows: Beginning at a point three miles west of the mean low-water line along the Bay Closing Line between Brant Rock in the town of Marshfield and Race Point in Provincetown as established on the Marine Boundary Map of the Commonwealth (prepared by the Department of Public Works, Division of Waterways, December, 1971, pursuant to Chapter 810 of the Acts of 1970 and Chapter 1035 of the Acts of 1971); thence swinging in a clockwise arc along a line three miles offshore and parallel to the mean low-water line of the northerly extremity of Cape Cod to the point of intersection with the Exterior Line of the Commonwealth as established on the aforementioned Marine Boundary Map; thence in a generally easterly and then southerly direction along said Exterior Line to the intersection with a line running due east (50 Degrees True) from a point three miles due south (180 Degrees True) of the mean low-water line at the southernmost point of Monomoy Point in the town of Chatham; thence westerly on said line to the point three miles due south (180 Degrees True) of the mean low-water line of the southernmost point of Monomoy Point; thence running due north (0 Degrees True) to the mean low-water line at Monomoy Point; thence along the mean low-water line of the eastern side of Monomoy Island and thence by the shortest distance to the seaward boundary of the Cape Cod National Seashore, as established by Act of Congress (1961, P.L. 87–126); thence easterly, northerly, westerly, and finally southwesterly along the seaward boundary of said Cape Cod National Seashore to the point of intersection with the aforementioned closing line, then westerly along said closing line to the point of beginning; and meaning and intending to include Town Cove and Nauset Harbor and portions of the Atlantic Ocean.

(b) The Cape Cod Bay Ocean Sanctuary is bounded and described as follows: That body of water known as Cape Cod Bay and lying southerly of the Bay Closing Line between Brant Rock in the Town of Marshfield and Race Point in the town of Provincetown as established on the aforementioned Marine Boundary Map of the Commonwealth, and lying seaward of the mean low-water line; meaning and intending to include: all of that water area and seabed lying in a southerly direction from the aforementioned closing line; all of Provincetown Harbor including portions which may be easterly or northerly of the aforementioned closing line, Wellfleet, Plymouth, and Barnstable Harbors; Plymouth, Kingston, and Duxbury Bays; and the Cape Cod Canal Northerly of the Bourne–Sandwich town boundary, and excluding the water area and seabed of the Cape Cod National Seashore as established by Act on Congress (1961, P.L. 87–126).

(c) The Cape and Islands Ocean Sanctuary is bounded and described as follows: Beginning at a point on the mean low-water line at the southernmost point of Monomoy Point; thence due south to a point in the Atlantic Ocean three miles due south (180 Degrees True) of the mean low-water line at the southernmost point of Monomoy Point; thence due east (90 Degrees True) to the Exterior Line of the Boundary of the Commonwealth as established on the aforementioned Marine Boundary Map; thence in a generally southerly and then westerly direction along said Exterior Line to the point of intersection with the extension of the lateral boundary of Rhode Island and Massachusetts; thence northerly along said lateral boundary to the mean low-water line near Quicksand Point; thence following the mean low-water line around Buzzards Bay, the Cape Cod Canal to the Bourne-Sandwich town boundary, and the southern portion of Cape Cod to the point of intersection in Pleasant Bay with the western boundary of the Cape Cod National Seashore; thence southerly along said boundary; thence by the shortest distance to the mean low-water line of Monomoy Island; thence to the point beginning by following the mean low-water line of the western side of Monomoy Island; and meaning and intending to include the area seaward of the mean low-water lines of Nantucket, Martha's Vineyard, Elizabeth and other islands; and meaning and intending to include the following bodies of water: Nantucket Sound, Vineyard Sound, Buzzards Bay, the Cape Cod Canal, Pleasant Bay, and portions of the Atlantic Ocean.

(d) The North Shore Ocean Sanctuary is bounded and described as follows: Beginning at the mean low-water line at the southeasternmost point of Pickworth Point in the town of Manchester-by-the-Sea; thence by a line bearing (150 Degrees True) (South-southeasterly) seaward to a distance of three miles to a point (42 Degrees 31.13&sprime; north, 70 Degrees 43.87&sprime; west); thence due east (90 Degrees True) to the point of intersection (42 Degrees 31.13&sprime; north, 70 Degrees 36.70&sprime; west) with the Exterior Line of the Marine Boundary of the Commonwealth as established on the aforementioned Marine Boundary Map; thence northerly, northeasterly, northwesterly, westerly, southwesterly, and northerly along said Exterior Line to the point of intersection with the extension of the lateral boundary of New Hampshire and Massachusetts; thence westerly along said lateral boundary to the line of mean low-water; thence southerly, northeasterly, southeasterly, southerly, and southwesterly, along the line of mean low-water to the point of place of beginning; and meaning and intending to include Gloucester Harbor; Ipswich and Essex Bays; Plum Island Sound; the Merrimack River Estuary; and portions of the Atlantic Ocean.

(e) The South Essex Ocean Sanctuary is bounded and described as follows: Beginning at the mean low-water line at the southeasternmost point of Pickworth Point in the town of Manchester-by-the-Sea; thence by a line bearing (150 Degrees True) (South-southeasterly) seaward to a distance of three miles to a point (42 Degrees 31.13&sprime; north, 70 Degrees 43.87&sprime; west) thence due east (90 Degrees True) to the point of intersection (42 Degrees 31.13&sprime; north, 70 Degrees 36.70&sprime; west) with the Exterior Line of the Boundary of the Commonwealth as established on the aforementioned Marine Boundary Map; thence southerly along said Exterior Line to a point (42 Degrees 26.10&sprime; north, 70 Degrees 38.42&sprime; west) thence due west (270 Degrees True) along a line a point (42 Degrees 26.10&sprime; north, 70 Degrees 52.02&sprime; west) which is three miles from the mean low-water line on a line which is the extension of the boundary line between the city of Lynn and the town of Swampscott thence northwesterly along said boundary extension to the mean low-water line; thence easterly, northeasterly, northwesterly, southwesterly, northeasterly, northwesterly, and northeasterly along the line of line of mean low-water of the commonwealth to the point or place of beginning; and meaning and intending to include Marblehead Harbor, Salem Harbor, Beverly Harbor, Salem Sound, Manchester Bay, and parts of Massachusetts Bay.

''Miles'', as used in this section, means nautical miles. ''Mean low-water line'' shall mean the arithmetic mean of the low-water heights observed over a specific 19–year Metonic cycle (the National Tidal Datum Epoch) and shall be determined using the nautical charts, harbors charts series (1:50,000 and larger) prepared by the National Ocean Survey, U.S. Department of Commerce. For those coastal areas not covered by such published harbor charts, the mean low-water line shall be determined using hydrographic survey data obtainable from the National Ocean Survey. Save for the degree bearings given herein, the compass directions provided in this act are general approximations of the directions of the boundaries of the sanctuaries; in all cases the mean low-water line shall follow the mean low-water line as determined from said charts or data, however it may wend or meander. Such Ocean Sanctuaries shall include all islands lying within the aforedescribed boundaries seaward of the mean low-water lines of each such island.

Notwithstanding the foregoing, the landward boundary of each ocean sanctuary shall be seaward of the mean low-water line in all rivers, bays, harbors, and coves at the point where the distance between the mean low water lines on either side is two hundred yards or less. The department shall have the regulatory authority to change from time to time the landward boundary of an ocean sanctuary to extend inward in rivers, bays, harbors, or coves to include environmentally sensitive areas. Such changes shall be reflected on the official ocean sanctuaries map.