Such resources are now considered on a case by case basis. Activists have long pushed for a more comprehensive approach.
"It's a monumental step forward for ocean conservation and stewardship," said environmentalist Priscilla Brooks of the Conservation Law Foundation. "This will provide a blueprint to enable the state to balance commercial use, personal recreation and the protection of underwater ocean habitats and wildlife."
A 17-member Ocean Advisory Commission will help the state environmental secretary develop the plan over the next 18 months. The panel will be assisted by an ocean science advisory council, consisting of nine scientists.
"This law will help protect our vital natural resources and balance traditional uses with new ones, such as renewable energy," Patrick said during a bill-signing ceremony, with Boston Harbor as a backdrop.
The management plan will cover everything from cruise ships and recreational sailing to commercial activities like liquefied natural gas terminals, wind turbines and the sand and gravel industry -- even the cod, a fish so central to the state's early development that a carving of the "sacred cod" still hangs in the Massachusetts House chambers.
The state's miles of coastal waters -- from the fishing port of New Bedford to the beaches of Cape Cod and the vacation hotspots of Nantucket and Martha's Vineyard -- are increasingly under pressure from development.
One of the most contentious projects is a proposal by Cape Wind Associates to build 130 windmills across 25 miles of federal waters in Nantucket Sound. The cables bringing the power to land would run through state waters. There's nothing in the new law to block the project.
A second offshore wind farm has been proposed near Buzzards Bay and a company pushing for a liquefied natural gas terminal near Fall River is floating the idea of building an offshore berth that would allow tankers to unload the liquefied natural gas into a four-mile pipeline.
The law specifically allows for "appropriate scale" offshore renewable energy facilities in state waters, except for the waters off the Cape Cod National Seashore.
Other states, like California, have laws in place to create marine conservation areas, but Massachusetts' law is more comprehensive.
"This is really looking at opportunities for renewable energy, opportunities to better manage coastal habitats," said Tom McCann of the Ocean Conservancy. "It's going to provide a road map for the rest of New England and the country."