Foreign or domestic?

Our view : Latest study documents the rewards - and many risks - of Asian oysters, but it's wrong to gamble when the Chesapeake Bay's native species still has a fighting chance

October 10, 2008

It's pleasant to imagine that all that ails Maryland's once-thriving oyster industry could be swept away if a few healthy, disease-resistant Asian oysters could be tossed into the Chesapeake Bay and given a little privacy. Instead of harvesting 80,000 bushels, watermen might return to harvesting a couple of million.

But the reality of what researchers have found these last four years studying the potential impact of introducing Asian oysters is quite different. Their work raises so many questions that it's hard to believe that such a move is worth the risk - or even necessarily would produce the desired results.

Are fast-growing Asian oysters more resistant to MSX and dermo, the diseases that have so plagued the bay's native species of oyster? It appears so, but as a draft environmental impact statement to be released next week concludes, introducing them into the bay could also edge out the native oyster and cause unknown damage to coastal ecologies up and down the eastern seaboard.

Introducing nonnative species of most any kind is a tricky business. Just consider such invaders as marsh-damaging nutria or mute swans that have competed with native waterfowl and gobbled up precious underwater aquatic vegetation.

It's also important to note that even if the Asian oyster were to be introduced, it would take more then a couple of frisky bivalves. Advocates contemplate large-scale hatchery production over many years and hundreds of millions of dollars in investment.

Make no mistake, Maryland would benefit enormously from a robust oyster population. As filter feeders, oysters can remove excess nitrogen from the water. That, in turn, could help the underwater grasses thrive and return dissolved oxygen to what are now dead zones.

But why not make that same kind of large-scale investment in the native species? Already, scientists are trying to breed native oysters for disease resistance. In shallow, less-saline waters, oysters have a much better chance of survival, particularly if they are not destined for commercial harvest. Maryland has invested prudently in oyster cultivation and research in recent years. There have been successes. But we need more oyster farming, more protected oyster sanctuaries and less harvest pressure on the wild stock - something a flourishing shellfish aquaculture industry could provide.

The case for introducing Asian oysters to the Chesapeake is far from a slam dunk. And until the benefits are proved to be worth the risks, better to redouble our efforts to revive the native variety.

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