Oyster Research Project Spawns Post-Ivan Reef Restoration

An Auburn University research project designed to pump up the state’s oyster industry by breeding an oyster that can tolerate stressful periods of low or no oxygen has had an unforeseen benefit in the aftermath of Hurricane Ivan: It has helped replenish the Alabama Gulf Coast’s largest commercial oyster reef.

Earlier this month, a crew of marine biologists from the AU Shellfish Laboratory on Dauphin Island, in cooperation with the Alabama Department of Conservation and Natural Resources’ Marine Resources Division, dropped some 55,000 fingernail-size oysters that were being raised as part of the lab’s low-oxygen-tolerant-oyster project into Mobile Bay around Cedar Point Reef, in a move to help put the Ivan-ravaged reef on the road to recovery. Ivan destroyed an estimated 80 percent of the oysters on that reef as the major Category 3 hurricane stormed Alabama’s Gulf Coast Sept. 16.

The 55,000 juvenile oysters that the lab planted were “extras,” surplus oysters from the low-oxygen experiment, said Rick Wallace, director of the AU Marine Extension and Research Center, of which the lab is a part.

"Our original plan had been to put these oysters on a reef that’s closed to public harvesting and to monitor them for growth and other data, but Ivan caused us to rethink that plan,” Wallace said.

The donation does not jeopardize the study, Wallace said, noting that the lab kept 15,000 juveniles to continue that research effort.

Low dissolved oxygen levels are a problem in shallow estuaries such as Mobile Bay, where reefs are no more than four to six feet beneath the water’s surface. Periods of low oxygen in the water can last anywhere from two hours to several days. The brief drops don’t pose problems, but extended low-oxygen conditions can stress animals and take a heavy toll on the population. No oxygen for more than five days will wipe out a reef.

The low-oxygen study began after Wallace and his team observed that some reefs along Alabama’s Gulf Coast are located in environments that have naturally occurring cycles of low oxygen, and that apparently the oysters in those environments have evolved over time to survive the low-level periods.

"That suggests that there may be a genetic basis for tolerance,” Wallace said. “Our theory is that oysters can be selected and bred for tolerance to low oxygen in the same manner that oysters have been selectively bred for disease resistance.

"If so, our findings will help restore failing oyster reefs and expand existing ones.”

For Wallace, donating the young oysters was rewarding professionally and personally.

"Auburn University strongly supports Alabama’s oyster industry and is committed to helping establish healthy, viable oyster reefs,” Wallace said. “But most important, oystering is the economic lifeblood of some of these smaller towns, like Bayou La Batre. With the value of landings expected to drop significantly this year, that’s going to be painful, both to individual oystermen and to their communities.”

Wallace said it will be 12 to 18 months before the fingernail-size oysters he and his crews deposited on Cedar Point Reef reach the minimum harvest size of three inches, and he acknowledged that AU’s 55,000 oysters are only a fraction of the oysters needed to restore the hundreds of thousands swept away or buried by Ivan. He did note, however, that most of the donated oysters will be mature enough to start spawning in the spring and that they are highly prolific reproducers, with one female releasing as many as 70 million eggs in a spawning season.

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Auburn, AL 36849
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Contact Jamie Creamer, 334-844-2783 or jcreamer@auburn.edu

10/14/04

For immediate release