A Caution Against Interpreting and Quantifying Oyster Habitat Loss from Historical Surveys

Abstract

Comparisons of historical surveys and fishery data have led to the popular belief that during the past century, more than 90% of oyster habitat has been lost through overfishing, disease, storms, and alterations to water quality and natural flow in the state of Georgia. Using handheld GPS computers, we conducted an on-the-ground inventory of living intertidal oyster reefs at four separate locations, and have concluded that previous surveys were not comprehensive or accurate enough to facilitate a reliable quantitative assessment of habitat loss. Alternatively, we have shown that intertidal oyster reefs are remarkably resilient and may occur in greater abundance today than when first documented in 1891. Rather than a collapse of oyster stocks, declining trends in fishery landings reflect the social and economic challenges associated with an unsustainable canning industry during the early 20th century. In addition, we challenge the axiom that the condition of existing intertidal reef habitat has deteriorated. Areas of shell deposits attributed to exhausted beds in historical assessments may in fact represent naturally occurring coastal features. Nonetheless, enhancement and conservation efforts are worthy efforts, because intertidal oyster habitat increases the health and resiliency of coastal Georgia by providing essential fish habitat, flood control, erosion abatement, and pollution reduction services. We propose that detailed GIS inventories like the ones conducted in this study can establish accurate baseline data to document reliably future changes in distribution, abundance, and condition, particularly with respect to the growing threats from development, sea level rise, and ocean acidification.