08/30/2002

Restoring Oyster Reefs in Mobile Bay

AUBURN, Ala. –Oyster reefs are a source of significant economic and ecological value in estuaries such as Mobile Bay, Alabama. And restoring oyster reefs and oyster populations is one of several Auburn University Peaks of Excellence projects.

According to Rick Wallace, professor in the Peaks of Excellence Research Initiative in the Department of Fisheries and Allied Aquacultures at Auburn, oysters impact not only the seafood market but the environment as well.

“Oyster reefs provide food and shelter to a host of organisms that, in turn, nourish some 300 species of fish and shellfish, many of which are economically important,” said Wallace, who also is a marine specialist with the Alabama Cooperative Extension System. “And oysters improve water quality in the Mobile Bay estuary by filtering tremendous quantities of algae and some suspended organic matter.”

In short, oysters are important for lots of reasons. However, despite the fact that they have sustained life and cleaned our waters for centuries, oysters are facing some challenges in the modern world.

Oyster bed productivity has been declining through the years and oyster yields are erratic. Wallace said that Alabama has harvested an average of one million pounds per year since the 1880s. However, large fluctuations occur on a year-to-year basis. For example, 1.5 million pounds of oysters were harvested in 1982 while only 336,000 pounds were harvested in 1983.

Wallace explained that oysters’ immobile lifestyles may partially explain the declines. Because oysters remain in one location once their larvae settle on a substrate, they are at the mercy of the water brought to them by currents and tides. If the water is too fresh or too salty, they can die. They also can be smothered by sand and silt from dredging operations or extremely heavy storms. Thus, any environmental changes – be they caused by Mother Nature or human activity – can severely affect oysters.

The Marine Resources Division (MRD) of the Alabama Department of Conservation and Natural Resources conserves oysters by requiring licenses, enforcing a harvest size limit of three inches and allowing only hand or oyster tong harvest on public reefs. The MRD also has worked to rejuvenate declining oyster reefs by augmenting them with additional oyster shells and planting hatchery-grown oysters on the sites.

Several oyster studies and outreach activities also are underway in Mobile Bay, including an oyster gardening project that enlists local residents to grow young oysters in bags or cages off their docks. These oysters are nurtured all summer in the containers and then transferred to natural waters. This project, which is co-sponsored by the Mobile Bay National Estuary Program and the Mississippi-Alabama Sea Grant Consortium, is in its second year and 36 residents are participating. Last year volunteers grew some 40,000 oysters that were used at three existing reefs to supplement oyster populations.

This year, all the gardened oysters will be placed at one site. “We hope to put up to 80,000 oysters in an area that will be protected from harvest and may serve as a breeding population,” Wallace said.

“We plan to do more research on all aspects of oyster production in the future,” continued Wallace. “The result could be cleaner water and an improved oyster fishery for Alabama.”

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News from:

Office of Ag Communications & Marketing

Auburn University College of Agriculture
Alabama Agricultural Experiment Station
3 Comer Hall, Auburn University
Auburn, AL 36849
334-844-4877 (PHONE) 334-844-5892 (FAX)

Contact Jamie Creamer, 334-844-2783 or jcreamer@auburn.edu
Contact Katie Jackson, 334-844-5887 or smithcl@auburn.edu

August 2002