calit thehe dead zone, and this c be upo 4040% of the volume of t b bay n the summe s so thiss s a vere assau to thsystem.. >>>> thehe oters are removing thaat algae, carining up thehe water thatetets sunligight penetrate deeper to sea grasses and other bottom dwelling plants so that they can photosynthesize, the more oysters you remove from the system, the less filtration popower you have.. >> so, when we're restoring oysters to the bay, oyster reefs, oyster bars, oysters in numbers approaching what they might have once been, you are replacing that filter. >> restoration is almost the wrong word to use, i'd say, because it assumes we're going back to some time in the past. there's no getting back to the way things were. we don't have the water quality we had, but we have, you know, millions of people living in the chesapeake bay watershed, and so it's not feasible to go back. the way to look at it is, where do we want to go from here under the conditions that we have now. we want to restore oysters in our sanctuaries to particular densities. we're looking at a density of 50 oysters per meter