Supporting Conservation of Mesquite Bay Reefs

Coastal habitats are recognized for providing ecological benefits and supporting coastal resiliency. However, the Texas coast is vulnerable to pressures from natural disasters and human activities. Crassostrea virginica oyster reefs rank highest among degraded marine systems, with an estimated 50-85% loss throughout the Gulf of Mexico. Loss of reef habitat translates into loss of biodiversity and associated ecosystem services, including viable fisheries habitat provision, and water filtration.

Conservation and restoration of oyster reefs can help communities become more resilient by providing natural buffers against storms, improving water quality, supplying critical habitat, and supporting coastal recreation and tourism. In the Texas Coastal Bend, Second Chain of Islands, Ayres Reef, Third Chain of Islands, Cedar Reef, and Carlos Reef (hereafter referred to collectively as ‘Mesquite Bay Reefs’) are historically productive oyster reefs that support colonial waterbird populations and attenuate waves from passing vessels passing between the Mission-Aransas and Guadalupe Estuaries. However, in recent years, reduced oyster densities and overall degradation of reef habitat have been observed, likely due to the effects of Hurricane Harvey and ongoing commercial harvest activities (i.e. dredging). Second Chain of Islands, Third Chain of Islands, and Carlos Reef appear to have experienced the greatest declines, thus there is strong interest in protecting, conserving, and restoring the remaining Mesquite Bay Reef habitat. The purpose of this study is to assess historical data and collect new data to support future conservation and restoration of Mesquite Bay Reefs, which may include: (1) obtaining TGLO surface leases to conduct oyster reef restoration activities, (2) working with TPWD to target oyster cultch placement efforts to these reefs, and (3) bringing a request to the TPWD Commission for closure of these reefs to limit commercial harvest and allow oyster population recovery.


1. Determine densities and size distribution of oysters on Mesquite Bay Reefs during spring and fall recruitment periods.

2. Evaluate trends in oyster relative abundance and size using TPWD Fisheries Independent Monitoring Program data.

3. Investigate potential changes in physical reef structure using historical aerial imagery.

4. Assess colonial waterbird use of the reefs using CBBEP Coastal Bird Program data.

5. Examine trends in larval supply using UTMSI/NERR monitoring data.