Robert D. Brumbaugh

Oyster Reefs at Risk and Recommendations for Conservation, Restoration, and Management

Native oyster reefs once dominated many estuaries, ecologically and economically. Centuries of resource extraction exacerbated by coastal degradation have pushed oyster reefs to the brink of functional extinction worldwide. We examined the condition of oyster reefs across 144 bays and 44 ecoregions; our comparisons of past with present abundances indicate that more than 90% of them have been lost in bays (70%) and ecoregions (63%). In many bays, more than 99% of oyster reefs have been lost and are functionally extinct. Overall, we estimate that 85% of oyster reefs have been lost globally. Most of the worlds remaining wild capture of native oysters (> 75%) comes from just five ecoregions in North America, yet the condition of reefs in these ecoregions is poor at best, except in the Gulf of Mexico. We identify many cost-effective solutions for conservation, restoration, and the management of fisheries and nonnative species that could reverse these oyster losses and restore reef ecosystem services.

Economic Valuation of Ecosystem Services Provided by Oyster Reefs

Valuation of ecosystem services can provide evidence of the importance of sustaining and enhancing those resources and the ecosystems that provide them. Long appreciated only as a commercial source of oysters, oyster reefs are now acknowledged for the other services they provide, such as enhancing water quality and stabilizing shorelines. We develop a framework to assess the value of these services. We conservatively estimate that the economic value of oyster reef services, excluding oyster harvesting, is between

Historical ecology with real numbers: past and present extent and biomass of an imperilled estuarine habitat

5500 and

CONTEMPORARY APPROACHES FOR SMALL-SCALE OYSTER REEF RESTORATION TO ADDRESS SUBSTRATE VERSUS RECRUITMENT LIMITATION: A REVIEW AND COMMENTS RELEVANT FOR THE OLYMPIA OYSTER, OSTREA LURIDA CARPENTER 1864

99,000 per hectare per year and that reefs recover their median restoration costs in 2–14 years. In contrast, when oyster reefs are subjected to destructive oyster harvesting, they do not recover the costs of restoration. Shoreline stabilization is the most valuable potential service, although this value varies greatly by reef location. Quantifying the economic values of ecosystem services provides guidance about when oyster reef restoration is a good use of funds.

Integrating societal perspectives and values for improved stewardship of a coastal ecosystem engineer

Historic baselines are important in developing our understanding of ecosystems in the face of rapid global change. While a number of studies have sought to determine changes in extent of exploited habitats over historic timescales, few have quantified such changes prior to late twentieth century baselines. Here, we present, to our knowledge, the first ever large-scale quantitative assessment of the extent and biomass of marine habitat-forming species over a 100-year time frame. We examined records of wild native oyster abundance in the United States from a historic, yet already exploited, baseline between 1878 and 1935 (predominantly 1885–1915), and a current baseline between 1968 and 2010 (predominantly 2000–2010). We quantified the extent of oyster grounds in 39 estuaries historically and 51 estuaries from recent times. Data from 24 estuaries allowed comparison of historic to present extent and biomass. We found evidence for a 64 per cent decline in the spatial extent of oyster habitat and an 88 per cent decline in oyster biomass over time. The difference between these two numbers illustrates that current areal extent measures may be masking significant loss of habitat through degradation.

Ecosystem services related to oyster restoration

ABSTRACT Reefs and beds formed by oysters such as the Eastern oyster, Crassostrea virginica and the Olympia oyster, Ostrea lurida Carpenter 1864† were dominant features in many estuaries throughout their native ranges. Many of these estuaries no longer have healthy, productive reefs because of impacts from destructive fishing, sediment accumulation, pollution, and parasites. Once valued primarily as a fishery resource, increasing attention is being focused today on the array of other ecosystem services that oysters and the reefs they form provide in United States coastal bays and estuaries. Since the early 1990s efforts to restore subtidal and intertidal oyster reefs have increased significantly, with particular interest in small-scale community-based projects initiated most often by nongovernmental organizations (NGOs). To date, such projects have been undertaken in at least 15 US states, for both species of dominant native oysters along the United States coast. Community-based restoration practitioners have used a broad range of nonmutually exclusive approaches, including: (1) oyster gardening of hatchery-produced oysters; (2) deployment of juvenile to adult shellfish (“broodstock”) within designated areas for stock enhancement; and (3) substrate enhancement using natural or recycled man-made materials loose or in “bags” designed to enhance local settlement success. Many of these approaches are inspired by fishery-enhancement efforts of the past, though are implemented with different outcomes in mind (ecological services vs. fishery outcomes). This paper was originally presented at the first West Coast Restoration Workshop in 2006 in San Rafael, California and is intended to summarize potential approaches for small-scale restoration projects, including some emerging methods, and highlight the logistical benefits and limitations of these approaches. Because the majority of the past efforts have been with C. viriginica, we use those examples initially to highlight efforts with the intent of enlightening current west coast United States efforts with Ostrea lurida. We also discuss site-specific characteristics including “recruitment bottlenecks” and “substrate limitation” as criteria for identifying the most appropriate approaches to use for small-scale restoration projects. Many of the included “lessons-learned” from the smaller-scale restoration projects being implemented today can be used to inform not only large-scale estuary wide efforts to restore C. virginica, but also the relatively nascent efforts directed at restoring the United States west coasts native Olympia oyster, Ostrea lurida.

Quantifying the Loss of a Marine Ecosystem Service: Filtration by the Eastern Oyster in US Estuaries

Oyster reefs provide coastal societies with a vast array of ecosystem services, but are also destructively harvested as an economically and culturally important fishery resource, exemplifying a complex social-ecological system (SES). Historically, societal demand for oysters has led to destructive and unsustainable levels of harvest, which coupled with multiple other stressors has placed oyster reefs among the most globally imperiled coastal habitats. However, more recent studies have demonstrated that large-scale restoration is possible and that healthy oyster populations can be sustained with effective governance and stewardship. However, both of these require significant societal support or financial investment. In our study, we explored relationships among how coastal societies (1) perceive and value oyster ecosystem services, (2) recognize and define problems associated with oyster decline, and (3) perceive or support stewardship initiatives. We specifically focused on the SES of eastern oysters (Crassostrea virginica) and coastal societies in the northern Gulf of Mexico, a region identified as offering among the last and best opportunities to sustainably balance conservation objectives with a wild fishery. We found that, in addition to harvest-related benefits, oysters were highly valued for providing habitat, mitigating shoreline erosion, and improving water quality or clarity. Our results also showed that although most respondents recognized that oyster populations have declined, many respondents characterized the problem differently than most scientific literature does. Among a variety of initiatives for enhancing sustainability, spawning sanctuaries and reef restoration were well supported in all states, but support for harvest reductions was less consistent. Our study suggests that public support for maintaining both harvest and ecosystem services exists at societal levels and that enhancing public awareness regarding the extent and causes of oyster decline could garner additional support for stewardship initiatives. Collectively, the societal, economic, and biophysical complexities of the northern Gulf of Mexico oyster SES illustrate the need and public support for developing more comprehensive management schemes for exploited ecosystem engineers.