Louisiana oysters spared a threat from an Asian cousin

 

 

 

It is rare but gratifying to report unequivocally good news on an important coastal issue. First, some background.

Can you think of a species of animal that fits the following description: lives in brackish coastal waters from Nova Scotia to Brazil; swims for about three weeks as an infant but never (willingly) moves again, during a lifetime that could last decades; filters and clarifies the water it lives in; can reduce benthic hypoxia; can change its sex from year to year; builds massive reefs that make ideal fishing habitat and bolster shorelines against erosion; can stay alive out of water for days or weeks; is highly tasty and nutritious to snails, flatworms, crabs, rays, bony fish, birds and mammals (including humans willing to pay perhaps $100/lb uncooked*); and contributes at least $25 million/yr directly to Louisiana growers? 

I just described the American or Eastern oyster, Crassostrea virginica.

After graduating from the University of Maryland in June 1963** with a BS degree in zoology I began a colorful coastal career. Thanks to a nice letter from the one professor who believed in me*** I became a research assistant at the Chesapeake Biological Laboratory at Solomons Island, south of Annapolis at the junction between the Patuxent River and Chesapeake Bay. For three years I worked on research projects aimed at restoring the oysters for which the Chesapeake Bay was formerly known around the world. 

Chesapeake Bay oysters (the same species that thrives in Louisiana) were in deep trouble when I was studying them but they have declined dramatically since I left Maryland in 1966.  Chesapeake oysters were overfished throughout the twentieth century, plagued since the 1960′s by diseases and stressed by sediments and other pollutants as the Chesapeake Bay watershed turned suburban from Philadelphia to Richmond. Today, odds are very high that a dozen raw oysters eaten in a Baltimore restaurant grew up in Louisiana waters.  

The last governor of Maryland, conservative Robert Ehrlich, came from a pro-business political background and during his tenure he became a supporter of the idea of restoring the commercial oyster fishery by importing a species of exotic Asian oyster (Crassostrea ariakensis) that is resistant to the oyster pathogens plaguing the native Chesapeake bivalves.

Ironically, this was the same governor under whose direction the Maryland State Police investigated Louisiana coastal hero Mike Tidwell (author, Bayou Farewell) as a possible terrorist because of his political opposition to climate change. The science community (including oyster scientists and growers in Louisiana) united against importing a cousin of the native oysters but $17 million and five years were squandered seriously studying the idea.

The 2008 takeover by Ehrlich’s successor, Governor Martin O’Malley, apparently tilted the politics back in a more pro-science direction, hence the good news that I mentioned above.  LaCoastPost librarian Frank Truesdale called my attention to a Washington Post article by David Fahranthold reporting that the standoff between business and science has been settled on the side of science. The Asian cousin of the American oyster will not be grown commercially in the Chesapeake Bay.

Why is this important to Louisiana?  Remember that I described our oyster as inhabiting a gigantic range all the way from Nova Scotia to Brazil.  An exotic cousin of our oyster, once established in the Chesapeake Bay, would not stay stay there.  

 

If any state has learned the hard way not to import exotic species for commercial reasons it should be Louisiana.  Even casual observers have heard about the massive damage to our coastal forests and marshes by nutria, unfortunately imported from Argentina during the 1920′s.  The extent of this damage is still being documented by researchers such as Gary Shaffer at Southeastern Louisiana University.  One further irony: the nutria has spread from Louisiana to Maryland, where it also does extensive damage to coastal marshes.

Len Bahr

*Based on, let’s say, $30/dozen at a harbor-view raw bar in Baltimore.

**Commencement speaker, Vice President Lyndon B. Johnson, who would become president in three months!

***A notable member of the emerging field of ecology from the Univ. of Wisconsin named Raymond Stross.