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Oso Bay: A Project to Assess the Oyster Waters Use

A current assessment project to determine whether indicator bacteria levels in Oso Bay are high enough to affect oyster beds in Corpus Christi Bay.
photo of Oso Bay
Satellite photo of Oso Bay
Courtesy of the Center for Coastal Studies

County: Nueces
Parameter: Bacteria
Coastal Basins: Bays and Estuaries, Nueces–Rio Grande Coastal Basin
Segment: 2485

Background and Goals

Oso Bay is an enclosed, shallow body of water situated along the southern shore of Corpus Christi Bay, with a surface area of approximately seven square miles. The bay exchanges saltwater with Corpus Christi Bay and receives fresh water from Oso Creek.Most of the flow in Oso Creek is discharged water from permitted facilities. Ecologically, Oso Bay provides habitat for many plants and animals, and plays an influential role in water purification and storm protection.

To protect consumers, the Texas Department of State Health Services designates, monitors, and classifies shellfish harvesting areas along the Texas coast. DSHS has identified Oso Bay, Segment 2485OW, as an oyster harvesting area and classified it as restricted. Although there are no oyster beds in Oso Bay, because it empties into Corpus Christi bay, it is considered part of the larger bay’s harvesting area.

The use of coastal waters for harvesting shellfish —called the “oyster waters use” in the state’s standards for surface water quality—is the most commonly impaired use among Texas coastal waters. Microorganisms from human and animal waste may contaminate oysters and other shellfish, making them unsafe to eat, especially since some shellfish are eaten raw. However, DSHS restrictions are based on their estimated risk of bacterial contamination rather than on actual measurements of bacteria in oysters or oyster waters.

In response to the oyster waters restriction, the TCEQ's Total Maximum Daily Load Program is gathering additional indicator bacteria data to assess water quality in the bay. The goal of the project is to determine whether the bacteria concentrations in Oso Bay exceed the criteria for oyster harvesting.

The TCEQ and area stakeholders are also working on a TMDL for bacteria in Oso Creek and have completed a TMDL for bacteria affecting recreational uses of Oso Bay.

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Get Involved

In all its TMDL projects, the TCEQ works with people who represent government, permitted facilities, agriculture, business, environmental, and community and private interests in the watershed. Notice of public meetings will be posted on this website and in print and electronic media.

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For More Information

Please send an e-mail to, and mention the Oso Bay Oyster Waters project in the subject line. Or call us at 512-239-6682.

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