YORKTOWN , Virginia ( CNN ) -- It 's daybreak on Sara Creek , a sleepy backwater that sits near Yorktown , Virginia , and empties into the Chesapeake . The early morning fog slowly lifts to reveal the ripples of water , the boats swaying , and a picturesque harbor . Tommy Leggett works to reduce polluted waters in Chesapeake Bay by growing oysters . Local watermen have been fishing around this area for generations . It 's beginning to rain , and Tommy Leggett , a very proud and reserved waterman , combs over his white beard with his rough hands and prepares his boat , `` Chesapeake Gold , '' for what looks like a day of fishing out in the bay . `` I 've been a waterman for over 20 years , '' he says . The difference now is Leggett does n't fish anymore . He 's an eco-conscious farmer and advocate who works on his sustainable oyster farm in the James River . He uses the term `` aquaculture '' to describe what he 's doing here . `` It refers to the husbandry , or farming , of aquatic species . '' Leggett sells the oysters he harvests to local restaurants , growing about 100,000 a year as a part-time business . He makes sure he always has a product to replace the ones that he sells . He shares his expertise with other watermen , educating them about oyster aquaculture and the importance of sustainability . Watch Leggett 's efforts to save the bay » . Leggett also sells his fresh products to the area market . `` Customers want to know if the oysters they are buying are local , which means they 're fresher and taste better . '' Waterman : Many foods rely on oysters . The Chesapeake Bay , which is the United States ' largest estuary , covering more than 64,000 square miles and spanning across several states , has seen its fish , crab and oyster stocks dwindle , in part , because of pollution over the past several decades . `` It was once said that the oyster stock in the Chesapeake Bay could have filtered the entire volume of the bay , in a single day , '' says Leggett , who has been farming shellfish in the watershed since 1995 . `` Most people do n't think of oysters having come from farms , and historically they have n't . They 've been harvested from the wild fishery , which is supplied by Mother Nature . '' That wild fishery , which still exists today , has seen its share of setbacks . From disease to overharvesting , Leggett knows what 's at stake , and he 's trying to get the message out . `` Oysters filter the water , and they provide habitat for other species . There are so many food webs that depend and rely on oysters . '' Not only does Leggett farm , he also works for the Chesapeake Bay Foundation ( CBF ) as the Virginia oyster and fishery scientist . He is trying to do his part to reverse the trends of depleting oyster stocks . `` If we do n't restore oysters , we 're not going to restore the Bay , '' he says . He wants to make sure people understand what just one single oyster can do . `` One oyster out here in one of our bags can filter as much as 50 gallons of water a day . '' By filtering the water , this important shellfish can take away deadly pollutants that eventually could deplete the crab and fish stocks , which in turn can leave fishermen without work . Millions of oyster 'moms and dads ' The CBF helps to grow millions of oysters that will eventually make their way to sanctuary reefs and will not be harvested . The oysters will reproduce , and make a home for thousands of sea critters that will eventually become food for larger animals . `` Its all a giant food chain , '' Leggett explains . Leggett works alongside Jackie Harmon as the CBF 's sole employees at a worksite near the Institute of Marine Science in Hayes , Virginia . iReport.com : Show us the environment near you . `` Our goal is to replenish oyster stocks , '' Harmon says , `` and by doing so , the oysters can not only help filter water , but also help with shoreline erosion . '' `` It 's a sustainable way for watermen of the Chesapeake to continue their livelihood as fishermen , in a more eco-friendly way . '' Harmon also maintains an oyster farm on the weekend and hopes to one day sell her oysters at local farmers ' markets . Leggett puts it this way : `` All we 're doing here is making moms and dads to help jump-start reefs throughout the Chesapeake . '' Leggett and Harmon are optimistic . They believe current federal and state administrations are doing great things for the environment . They believe the CBF 's message is being heard . However , a lot more needs to be done , Harmon says . `` People are becoming more aware and want to take care of their environment , and they want to make it a better place for future generations , '' she says . So as the land-based movement makes it apparent that buying local is the healthy way to live , seafood should be known in that same light . Leggett believes the Chesapeake Bay can produce the amount of seafood needed for the entire region and he thinks with careful oversight , the watersheds can be an abundant source for that local seafood industry again , just like it was decades ago .
NEW : Watch CNN.com Live Earth Day coverage at 4 p.m. , 7 p.m. , 9 p.m . ET . Pollution in United States ' largest estuary has reduced fish , crabs and oysters . Chesapeake Bay project aims to grow millions of oyster `` moms and dads '' Oysters can help crabs and fish flourish by filtering poisons from the water .