Research

My research is broadly focused on oyster ecology, conservation, and restoration.  Below is a sampling of some current and ongoing projects.

Oyster reef restoration – do restored reefs function like natural reefs?
We are conducting several ongoing oyster reef restoration projects to ask the overarching question: “Do restored reefs function like natural reefs?” These projects include a 4-acre subtidal reef complex in Copano Bay, TX, and a 2-acre subtidal reef complex in Aransas Bay. Both projects have used reclaimed oyster shells from coastal bend restaurants and seafood wholesalers as substrate. The reefs were constructed with higher vertical relief, similar to un-dredged reef structures in order to support higher oyster densities and larger populations of fish while reducing potential issues with sedimentation and hypoxia. These restoration projects are expected to result in increased oyster and sportfish abundance. Structural and functional characteristics of the reef complex are being monitored to determine short- and long-term success.
Characterizing the oyster reef community of Sabine Lake Estuary
Sabine Lake Estuary is located on the Texas-Louisiana border. The Estuary contains an extensive oyster reef complex that is likely the largest in the U.S. to remain in its natural, un-fished state. Due in part to substantial oyster mortalities as a result of the Macondo oil spill and subsequent freshwater releases, Louisiana has considered opening their side of the reef to commercial oyster harvest. This project seeks to characterize the oyster, finfish, and macroinvertebrate assemblage of this natural reef complex, and to determine the relative importance of natural oyster reef as habitat in comparison to nearby non-vegetated and marsh edge habitats. This work will provide insight into the community structure of a naturally functioning oyster reef system and the potential effects of habitat loss.
Suitability of alternative substrates as habitat for oyster reef restoration
Throughout Texas, because of a lack of oyster shells, many different substrates are being used to restore reefs, including crushed concrete, porcelain, limestone, and river rock. We are conducting field and laboratory experiments to determine the effectiveness of each substrate for attachment and growth of oysters, and also their relative suitability as habitat for fish and macroinvertebrates.
Spatial and temporal distribution of Perkinsus marinus in the Mission-Aransas Estuary
In partnership with Dr. Sammy Ray (Texas A&M University-Galveston), we conduct quarterly oyster sampling along a salinity gradient throughout Copano and Aransas Bays. The oysters are examined for the presence of Perkinsus marinus, a protozoan parasite that causes severe mortalities in Gulf of Mexico oyster populations. Disease prevalence is strongly linked to high salinities and temperatures. A section of mantle tissue is incubated in thioglycollate medium and then stained and examined under the microscope. We calculate both the percentage of oysters infected by P. marinus, and rank the infection intensity from uninfected to heavily infected.
A restoration suitability index model for the Mission-Aransas Estuary
For successful and sustainable oyster reef restoration efforts, it is necessary to choose sites that support long-term growth and survival of oysters. Selection of suitable sites is critically important as it can greatly influence mortality factors and may largely determine the ultimate success of the restoration project. This project uses a Geographic Information Systems (GIS) approach for identifying suitable sites for oyster reef restoration. The aim of this study is to develop a restoration suitability index model and reef quality index model to characterize locations based on their potential for successful reef restoration within the Mission-Aransas Estuary, Texas. The end product will be a practical decision-support tool that can be used by coastal resource managers to improve oyster restoration efforts.
Oyster shell recycling – “Sink Your Shucks”
Larval oysters need hard structures such as oyster reef for attachment and growth. However, in Texas, no mechanism exists for harvested oyster shells to be returned to bay waters. Rather, once the oysters have been eaten, large quantities of shells are typically discarded. Upland disposal of oyster shell disrupts the natural process of oyster reef growth and regeneration by depriving reefs of their most fundamental building blocks. What’s more, oyster reef restoration efforts are often limited by a shortage of available shell material. This project reclaims oyster shells from local restaurants and seafood wholesalers and stockpiles them for use in restoring degraded reefs. Associated activities include an economic assessment of oyster shell recycling and numerous community-based oyster restoration events.