Investing in oysters can help restore the environment and economy

11-03-2011 // Bob Serata

If all the oyster reefs are gone, where are all of those oysters-on-the-half-shell coming from?

An estimated 95 percent of oysters served for slurping come from oyster farms. Wild oysters have been fished out, developed out and smothered by river sediment. The nearly 5 million barrels of oil BP let loose in the Gulf of Mexico didn’t help either. But BP, or more accurately, BP’s money can help restore wild oyster reefs (and a whole lot more). The U.S. Senate and House of Representatives have introduced separate bills that would direct at least 80 percent of the Clean Water Act penalties levied on BP to Louisiana, Mississippi, Alabama, Florida and Texas to invest in the long term health of the environment and local economies.

Of course, “investing in local economies” covers a lot of ground, not necessarily in, on or adjacent to the Gulf of Mexico.

Restoring wild oyster reefs is a perfect microcosm of large-scale Gulf restoration

First, oyster restoration is do-able.Though the Gulf of Mexico has been neglected by research funding agencies, there’s some science trickling down from decades of studies of the Chesapeake Bay and Atlantic coast oyster fisheries. There’s new science, too, that takes a distinctly “applied” approach.

Dr. David Kimbro of Florida State University’s Coastal Marine Lab has been leading a multi-institutional study that could lead to a kind of best practices guide to oyster restoration along the eastern Gulf coast and southern U.S. Atlantic coast. He and his associates have been building and monitoring oyster reefs in 12 estuaries spanning 1,000 miles of Atlantic and Gulf of Mexico shoreline to learn under what conditions oysters flourish.

“I just started looking at the data and it looks like we are going to see differences among regions,” said Kimbro. It appears that Eastern Oysters (Crassostrea virginica), the primary harvest species in Gulf and mid-to-southern Atlantic coastal waters thrive in different conditions in different locations.

Separately, Dr. Joel Fodrie, of the University of North Carolina’s Institute of Marine Sciences, noted that intertidal oysters living on reefs built in the 1990s also are picky about their habitat. “In North Carolina, in really salty water, the reefs that were built out on the broad mud flats have done tremendously well, whereas the reefs that were built next to salt marsh or sea grass haven’t done nearly as well,” said Fodrie. “The explanations for why those differences occurred largely revolve around flow. For the reefs next to salt marsh, there may be a problem with food delivery or larval delivery because the water is kind of stagnant; or it may be because of the presence of little nibblers that can come out of the marsh or sea grass and chomp every single little settling oyster,” he added.

Fodrie and other researchers mapped the reefs in three dimensions. “The difference between success and failure in this system is about 10 centimeters,” said Fodrie. “If a reef was built at about 65 centimeters (25.6 inches) below mean water or deeper, ultimately that reef went nowhere. But if the reef was built above that at 55 centimeters (21.7 inches), just a 10 centimeter (3.9 inch) difference, the reef has done wonderfully,” he explained.

“The challenge is to find that sweet spot,” said Fodrie. “You can’t just throw the shell out and expect it to take off. Depending on what your tidal regime is at the reef’s location there’s probably a 10 to 20 to 30 centimeter range that you should be targeting. If it’s too deep, the reef doesn’t go anywhere, and if it’s too shallow you’ve eliminated so much potential for vertical growth that you do not maximize your resource,” he said.

Investing in oysters to restore the environment and economy

Which brings us to the next piece of the oyster microcosm puzzle: because oysters are good for their habitats, they provide what scientists call ecosystem services. Oysters are filter feeders. They remove some phytoplankton and a lot of nitrogen from their home water – good news for cleaning up fertilizer runoff from agriculture, golf courses and lawns.

Oyster reefs also provide nursery and foraging habitat for dozens of reef and game fish species. Once the reef grows tall enough, it begins to grow laterally, creating a protective barrier to shoreline marshes and shallows.

Finally, oysters are good for the economy. Thousands of people are employed in the Gulf oyster industry growing, harvesting, packing, selling, transporting, opening and serving oysters. Even jewelry makers create fashion accessories from oyster shells.

There are tourists who watch sunsets while eating oysters; shippers who send them to far off lands (like Washington, DC, and New York City); asphalt companies that mix ground up shells into road surfaces.

And there’s a new industry arising: companies that make oyster reef modules, transport them to restoration sites and place them in the water.

The Gulf oyster industry’s economic impact is far reaching. A paper published in July 2010 by the Virginia Institute of Marine Science at William & Mary College, said that the Gulf oil disaster generated “a total negative economic impact [i.e., the money didn’t come into the state] from ‘water to table’ of approximately $30.1 million statewide.” That’s just in Virginia, and that’s apart from the Chesapeake oyster industry’s economic and environmental woes.

As with any restoration project, whether it’s a historic home or a microcosm of a life-giving body of water, money is the great enabler. That’s why NWF helped launch an oyster reef restoration project in Mobile Bay, Ala. with a $50,000 contribution. But in this case, the money is going to be there without one penny coming from tax payers, permit holders or concerned citizens. The money will be there if our elected officials just raise their hands and say “Aye,” to support legislation that will send the fines levied on BP back to the Gulf for restoration.

Joel Fodrie said, “Restoration is inherently a local issue.” Raise your hand if you agree.


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