Saturday, September 12, 2009

Oyster Cloister

Oysters like to live in dense, complex, and silent comunities. Who knew?

Oysters have virtually vanished from the eastern seaboard, and numerous attempts at restoration and reintroduction have come to naught. The Chesapeake Bay, among many others, was once carpeted with reefs of oysters, cleaning the water and supplying abundant food to Native Americans and later to European settlers and townspeople. Technology allowed increasingly intensive removal, culminating in "power dredging", which strips the bay bed clean of ... pretty much everything.

Who would have suspected that oysters might not like to be dredged across time and time again, until nothing was left on the bottom to hang on to, but a slurry of silt and muck? Who would have guessed that "conditioning" the bay bottom by repeated dredging might not make it so great for the object of all that dredging ... the oyster?

The short-sightedness of man knows no bounds, especially when motivated by hunger and greed, and when the damage takes decades or even centuries to fully play out. But here we are, with species after species of bay and sea life fished out and stocks even in the supposedly limitless open ocean declining precipitously, or responding to fishing pressure by demographic collapse and selection for smaller adult sizes, among other issues. Whole ecosystems are being deranged. But the sea is the ultimate locus out-of-sight, out-of-mind. A ground-breaking paper some years ago outlined the full historical horror of what has happened to ecosystems that we so casually call "fisheries" (please contact me for the full paper if interested).

Getting back to oysters, a more recent paper demonstrates that oyster reefs can be brought back to vibrant and healthy condition within three years by the simple expedients of not dredging or killing them and of giving them a shoal-like bed of shells to live on. Here we are in the new millenium, having put a man on the moon, espied the smallest substituents of the atom and the farthest reaches of the cosmos and time, and it takes a major academic effort, published in the highest-profile journal in the world, to tell us that oysters thrive if they are given half a chance in a decent habitat? The paper proudly trumpets its success in its title: "Unprecedented restoration of a native oyster metapopulation". They even film their "happy" oysters blowing smoke rings!


Forgive my scoffing attitude, but while it certainly is good to hear about this triumph of oyster restoration (185 million oysters growing over 35 hectares = 86 acres, or 0.14 sq mile, equivalent to ~50 oysters per square foot), it also shows how blinkered and timid the fisheries-associated academy has become. (Here in collaboration with the Army Corps of Engineers.) Previous attempts at restoration apparently only used the naked bay floor as previously "conditioned" by the oyster dredgers, on which researchers seeded juvenile oysters, (called sprats), only to watch them succumb to disease and siltation/suffocation.

Here on the West coast, we have similar problems, including a decided lack of oysters. Our salmon runs are defunct or in freefall, after many decades of overexploitation, damming, and water diversion. California's central valley has been sucked dry and turned into a cesspool that will shortly be reversing flow and getting saline floodwater from the San Francisco Bay and ocean, due to our endless need for water, diking, dredging, as well as climate change-related draught. If we are to overpopulate the world, we should at least do so with a little consideration and foresight.

So, spare a thought for the lesser beings and the wild beauty of our world. Don't eat seafood.

1 comment:

  1. Sorry, I can't help myself... I finished reading your post, and all I can think of is the NOFX song "Clams Have Feelings Too" :-)

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