oxygen or infficient ogen to suprt highelife, we cl it t deadone, and is can beup to t by e summer, sthis ia severe assaulto the stem. so t oystersre removin that algae, clearg up the water that ls sunlight 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 power 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. >>estorations 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 squared, a