Abstract

Eastern oysters (Crassostrea virginica) are the keystone species of the marine ecosystem of the northern Gulf of Mexico coast, vitally important for improving water quality and for building and sustaining shallow reefs. Oyster reefs also serve as habitat for many other economically valuable species and can reduce coastal erosion from wave attack. Fundamental knowledge about the distribution and extent of oyster reefs and sediment types suitable for oyster cultch is nonexistent in all but a few of Louisiana’s shallow water settings. This study employs high-resolution acoustic techniques (side-scan sonar, CHIRP subbottom, and echo sounder bathymetric profiles) to map previously unknown oyster habitat in Vermillion Bay/West Cote Blanche Bay, Louisiana. Shallow subbottom acoustic profiling provides data on stratigraphy of the shallow subsurface and structure of the project area bottom, which is used to interpret substrate conditions as well as habitat data. The combined geophysical datasets provide a framework for understanding the sedimentological and to some extent the biological dynamics of the shallow water environment of the project area, critical for making informed oyster management decisions and the identification of optimal habitat placement. The georeferenced data collected serves as a permanent record of the surface and shallow subsurface location and spatial extent of the oyster reefs for future comparisons, and as a baseline dataset for restoration projects. Over 275 ac of optimum area for oyster cultch placement based on substrate conditions in the project area were identified.