08/15/2002

Oysters Vital to Alabama's Gulf Coast

AUBURN, Ala. – Oysters may seem to be passive creatures, but when it comes to the economy and ecology of Alabama’s Gulf Coast, they’re dynamic, vital players. Research underway through Auburn University’s Peaks of Excellence Program is helping ensure that oysters can continue to do their important work.

According to Rick Wallace, professor of fisheries and allied aquacultures at Auburn, oysters have always been important to Alabamians. The Southeast’s Paleo Indians used oysters for food, tools, jewelry and currency thousands of years before the first Europeans arrived. Early European settlers in America also used oysters for food and tools and even as construction material for buildings and roads.

Oysters developed into a cash crop and today Alabama’s oyster fishery contributes an estimated $3.4 million to the coastal economy annually. However, oysters populations are declining.

Low oxygen events (such as the Mobile Bay “jubilee” phenomenon), high sedimentation, a limited supply of newly hatched oysters (larvae) and limited oyster shell substrate for larvae to attach to are also suspected contributors to the decline of these once productive oyster reefs.

To answer questions about the declines and fluctuations in oyster populations and to increase oyster yield and quality for the food market, AU has been studying a wide range of oyster management programs for many years. David Rouse, now chair of the AU Department of Fisheries and Allied Aquacultures, and Wallace have spent more than 20 years exploring oyster issues.

In one Peaks project, AU researchers assessed Fish River Reef, which once covered about 70 acres along the Eastern Shore of Mobile Bay. This area contains several historically productive oyster reefs that are not producing commercial quantities of oysters despite the fact that these beds have not been fished commercially in many years.

According to Wallace, initial reef assessment studies in 1998 revealed low oyster density (less than 0.1 oyster per square yard) and a lack of shell substrate for larval oysters to settle on. Hatchery-produced oysters planted on the oyster shell plots at the reef grew well for more than a year and young oysters were found in the area.

In the second year of the study, low oxygen events (levels near zero) occurred in bottom water at the study site. In addition, sediment accumulated on the shell pads at rates greater than at productive reefs and killed all the young that summer.

Results of this study indicate that oyster larvae are present and they can attach and survive when adequate substrate is available. However, periodic low oxygen concentrations and possibly high sedimentation rates are contributing to the failure of some oyster reefs. Some of this problem may simply be where the oysters are located in the water profile.

Last year oyster shells were added to the areas to raise the oyster beds up off the bottom of the Bay and improve the survivability of the oysters by changing their location in the water stream.

“We’re monitoring that situation now,” Wallace said, “and this information is being used to formulate new strategies for oyster reef restoration projects in Mobile Bay.”

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Office of Ag Communications & Marketing

Auburn University College of Agriculture
Alabama Agricultural Experiment Station
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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