Chesepeake Bay was once known as "Great Shellfish Bay". In the 70's, they were harvesting almost 20 Million bushels of oysters a year. In 2004, they harvested just 26,000 bushels. (They shouldn't have harvested ANY by then.)
An oyster can filter 50 gallons of water in a day. Imagine what 20 Million bushels of them can do for the water quality in a bay. Now imagine what losing 20 Million bushels of them in a single year did to hurt the water quality in Chesapeake Bay.
Yes... oysters are prolific. But the population can crash just the same. We've seen it in our lifetimes in Chesapeake Bay, yet we still ignore it here. When the oyster population declines, water quality declines with it. When water quality declines, the oyster population declines, AND the ones that are left begin to succumb to diseases. It's a vicious cycle. One of the early signs is that there is a thin layer of living reef on top of flat, dead substrate (caused by constant dredging). We have that in our bays now, and if you don't believe it I can take you and show you.
It's not a question of whether some oysters will be around after humans are gone. It's about the health of the bays in between now and then. A thriving oyster population is vital to the overall health of the bays, and therefore everything that swims or crawls in them. A crash will do damage that will take more than our lifetimes to recover from. And I don't think we are too terribly far from that.
Certain people like to point to the "rebound" in Chesapeake Bay oysters, and the fact that they are now harvesting commercial quantities there once again. What they don't like to mention is that scientists are growing "triploid" oysters, and seeding Chesapeake Bay with them. Triploid means that they are genetically modified to have an extra set of chromosomes. It makes them more hardy and disease resistant. It also makes them sterile. So the rebound in oysters is really dependent on seeding the Bay with gazillions of little Frankenstein oysters every year, to give fishermen something to dredge up.
I've been watching the oyster boats struggle this year. They are going after that thin layer, and in places I have never seen them dredge before. They used to congregate, and spend a week or more in a single location. This year they are spread out, and I have watched them spend an hour or so in a location and then move on. You can spin it any way you want to, but it's a bad sign. The massive amounts of fresh water we had this past year are part of it, but it should tell anyone that we need to give some time for new, healthy reef to establish.
And just for the record - the oyster shells that are dredged up are NOT all thrown back to provide a future base for spat. Mountains of them are sold for driveways and other commercial uses. And the resulting amount of calcium carbonate that is lost is another detriment to the growth of new oysters. The loss of buffer leads to swings in pH, which is another problem. If you mean that they throw back small oysters, that just returns what was already there. You know that the harvested oysters aren't shucked on the water. They are shucked on land, and very little of the shell is returned to the water. They have started programs for it, partly because a few of us have screamed for decades about the loss of calcium carbonate.
I know what happens after I write this - the same thing that always happens. But the things I said are truth, and scientifically sound. We don't need for SOME oysters to survive until after we are gone. We need a large, thriving population and deep live beds, to regulate water quality and create new habitat in our lifetimes and our children's lifetimes. A thin layer growing on pilings means nothing.
