The Associated Press reports that volunteers from across the country are rebuilding oyster reefs along the Gulf of Mexico''s delicate shoreline, hoping to revive oyster beds under assault for decades from overharvesting, coastal development, pollution, and most recently the BP oil spill. The waters harbor much of the world''s last remaining productive natural oyster beds, but BP PLC''s April 20 oil well blowout dumped millions of gallons of crude into the Gulf and dealt yet another blow to the once bountiful habitat. Last weekend, volunteers descended on Mobile Bay with 23,000 bags of oyster shells aimed at eventually creating 100 miles of new oyster reefs near the shoreline. The goal is to help replenish oyster reefs that promote new growth, help protect delicate salt marshes and sea grasses, and act like coral in the tropics to provide habitat for numerous marine species. It''s one of the first coastal restoration projects since the oil spill sent thick crude washing into estuaries and onto beaches.