HRI Researcher Provides Data on Local Oyster Reefs to Inform Conservation, Management Decisions

CORPUS CHRISTI, Texas – A new Gulf Coast oyster reef conservation study has its roots in concerns expressed by anglers who are worried about oyster reef habitat losses and the cascading effects such losses would have on other marine organisms.

Near the Aransas National Wildlife Refuge are oyster reefs in the Mesquite, Carlos, and Ayres bays; while reefs in these bays make up a small portion of the total area of reefs in Texas, experts say these reefs have experienced high harvest pressure due to closures of historically productive areas across the coast. While reduced oyster densities and overall degradation of reef habitat has been caused in part by changes in freshwater and sediment inputs from droughts and storms, ongoing commercial harvest activities such as dredging have adverse impact on the reefs as well.     

To assess reef degradation caused by high harvest pressure as well as environmental factors, a research team with the Harte Research Institute for Gulf of Mexico Studies (HRI) at Texas A&M University-Corpus Christi (TAMU-CC) has started collecting data and conducting research on oyster reefs in Mesquite, Ayres, and Carlos bays – collectively referred to among team members as the Mesquite Bay Reefs – to support future conservation and restoration actions.  

The Coastal Bend Bays and Estuaries Program (CBBEP) provided $60,000 for the study.

“Understanding the Mesquite Bay Reefs through review of historical data and imagery is a critical step in developing effective solutions for their conservation and restoration, and the Coastal Bend Bays & Estuaries Program is excited to be supporting this effort,” said Rosario Martinez, CBBEP Senior Project Manager.

The team is led by Dr. Jennifer Pollack, TAMU-CC Associate Professor of Marine Biology and HRI Chair for Coastal Conservation and Restoration, and includes Dr. Terry Palmer, HRI Assistant Research Scientist; Dr. Mark Besonen, HRI Associate Research Scientist; and Natasha Breaux, HRI Research Specialist.

The team is completing field surveys to determine the size and abundance of oysters; it will also determine changes in relative oyster abundance and size using Fisheries-Independent Monitoring Program data collected by the Texas Parks and Wildlife Department (TPWD). Finally, the study will evaluate changes in physical reef structure using historical aerial imagery. 

“In the past few months, TPWD has temporarily prohibited commercial oyster harvests for many areas of the coast based on small numbers and low proportions of legal-sized oysters,” Pollack said. “The data and samples that we collect can provide a baseline of current conditions on oyster reefs in Mesquite Bay and can be compared against past and future data to understand what factors promote increases (or lead to declines) in habitat. These data are particularly important and timely given the potential for permanent closure of these harvest areas and the need to understand oyster population recovery when harvest activities are discontinued.”

At a Texas Parks and Wildlife Commission work session on Jan. 26, TPWD Coastal Fisheries staff requested permission to publish a proposal in the Texas Register, the journal of state agency rulemaking for Texas, for permanent closure of reefs in Ayres, Mesquite, and Carlos Bays to commercial oyster harvesting.

“If the Commission grants the Coastal Fisheries department permission to publish the proposed amendment in the Texas Register, a public comment period would then follow where TPWD staff would gather public comments. The proposal would then be considered for final adoption by the TPWD Commission at the next regular meeting in March,” Pollack said.

For this study, the HRI team is working with David Newstead from the CBBEP’s Coastal Bird Program to evaluate trends in bird usage of the reefs, and also with Dr. Edward Buskey, Interim Director of The University of Texas Marine Science Institute (UTMSI), to assess trends and changes in bivalve (oyster) larvae in historical zooplankton samples that have been collected in Mesquite Bay since 2007. Additional project partners include the Texas chapter of the nonprofit marine conservation organization Coastal Conservation Association, and the Fulton, Texas-based angler organization FlatsWorthy, which was instrumental in drawing attention to the need for science to address ongoing concerns for reef condition in the area. 

“This unique partnership brings together a diversity of perspectives and expertise to solve a problem and is a model for bringing science to solutions, which ultimately supports the HRI mission,” Pollack said.

Final data analysis will occur in June-July, and a report will be submitted to CBBEP in August 2022. 

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