Nonnative Oysters in the Chesapeake Bay (2004) / Chapter Skim
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6. History and Current Status of Restoring Native Oyster Reefs in the Chesapeake Bay
6. History and Current Status of Restoring Native Oyster Reefs in the Chesapeake Bay
Pages 120-149
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From page 120... ...
Currently, more emphasis is being placed on the ecological benefits of functioning oyster reefs in estuarine ecosystems, including values related to filtering capacity, structural fishery habitat, species diversity, and trophic dynamics. However, it is also important to understand that restoring productive oyster reef habitat is only one part of a complex problem, and resource managers and researchers must guard against the sentiment that oyster restoration can singularly resolve all of the ecological and environmental problems facing the bay.
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From page 121... ...
The oyster industry has long held that successful restoration could be measured by increased harvests, a perspective that has influenced fishery management policies for decades. Although increased economic benefit derived from increased landings is a legitimate measure
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From page 122... ...
Recent restoration efforts combine coordinated actions by state, federal, and private organizations under the mandates of Chesapeake Bay 2000 to restore and maintain the valuable ecological services provided by native oyster populations while continuing to support local oyster fishing interests. The following information represents a cursory review of the history of oyster restoration efforts in the Chesapeake Bay to identify the benefits and shortcomings of these programs and to evaluate the potential of future restoration programs.
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From page 123... ...
It is clear from the history of management in both Virginia and Maryland that poor management decisions, legislation, and failure to react to available scientific information have contributed to resource management problems. Historically, most management efforts were directed at sustaining the oyster industry as opposed to restoring oyster populations over the long term (Haven et al., 1981; Kennedy and Breisch, 1983; Rothschild et al., 1994; Tarnowski, 1999; Hargis and Haven, 1999~.
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From page 124... ...
Resource managers have now agreed on a more comprehensive approach to oyster resource management and oyster restoration. The holistic approach includes coordinated multifaceted management strategies to restore oyster populations to self-sustaining levels, to provide ecologically valuable reef habitat, to improve ecological services such as water quality, and to provide an economic benefit for resource users.
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From page 125... ...
. HISTORY OF OYSTER RESTORATION IN THE CHESAPEAKE BAY Restoration of oyster reefs as a practicable resource management strategy has been used in many oyster-producing regions for more than a century.
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From page 126... ...
In 1994 and 1995 the replenishment program in Virginia received two oyster disease research grants to develop and test protocols that take advantage of higher salinity for setting while reducing the impacts of oyster diseases (Wesson et al., 1999~. Until the mid-199Os almost all shell-planting efforts were directed toward the practice of creating new oyster reefs rather than maintaining existing natural oyster reefs.
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From page 127... ...
Most recently, the Chesapeake 2000 Agreement (see Appendix E) established oyster restoration goals to increase native oyster populations in the bay by a minimum of 10-fold by 2010 and to develop and implement a strategy to achieve this increase by using sanctuaries sufficient in size and distribution, aquaculture, continued disease research and diseaseresistant management strategies, and other approaches to restore native oyster productivity to the bay.
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From page 128... ...
These early restoration efforts, however, did not succeed in improving oyster harvests. In 1935 the state planning commission noted that depletion of the oyster resource could be traced to overfishing, exploitation of seed stocks, and a failure to return adequate supplies of cultch to the bay, which consequently resulted in a decline in oyster harvests and the demise of the oyster canning industry.
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From page 129... ...
After 40 years of dredging, sources of fossil shell are nearly exhausted. Oyster management practices in Maryland were primarily directed toward maintaining the fishery instead of restoring the functionality of oyster reefs.
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From page 130... ...
In 1993, Maryland convened the Oyster Roundtable with the goal of developing sound, broadly supported recommendations for reviving oyster populations in the bay. Specific objectives included maximizing and enhancing ecological benefits, maximizing and enhancing economic benefits derived from harvest from public and private oyster grounds, and maximizing the ability of government to respond effectively to the magnitude of the problem.
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From page 131... ...
Currently, the Maryland Department of Natural Resources Shellfish Division is responsible for maintenance and restoration of the state's oyster populations. Key elements in efforts to restore native oysters include habitat restoration, disease research, hatchery seed production, sanctuaries, and reserves.
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From page 132... ...
Direct benefit to oyster-dependent businesses will result from longterm resource recovery. CURRENT OYSTER RESTORATION PROGRAMS The Chesapeake Bay Program sponsored an Oyster Restoration Workshop in January 2000 to address issues related to current oyster restoration efforts that might lead to revising the Aquatic Reef Habitat Plan and the Oyster Management Plan (Chesapeake Bay Program, 2000~.
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From page 133... ...
Restoring oyster populations should lead to: · increased oyster populations that ultimately form self-sustaining reef communities that contribute to species diversity, trophic dynamics, and community stability; functional reef communities that perform specific ecological services contributing to the overall water quality, nutrient cycling, hydrodynamics, and habitat aspects of the estuarine system; and increased harvests that result in revenues that provide economic benefits to all sectors of the oyster industry.
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From page 134... ...
(1999) provided an overview of past restoration efforts and preliminary results from contemporary oyster restoration programs.
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From page 135... ...
The atlas compiles a series of maps that summarize historical and current data relevant to oyster distribution and restoration efforts and provides details about the location, history, current status, and restoration potential for 30 individual projects. Restoration potential was categorized as modest at five sites because of low spat set, moderate or consistent disease risk, and high freshet risk.
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From page 136... ...
Although numerous management strategies include disease management, none have proven to be successful in the long term. Experimental restoration efforts in Maryland have focused on experimental design to compare various population parameters (density, longevity, mortality)
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From page 137... ...
A group of oyster experts met in 1999 to develop recommendations to restore and protect the oyster resources of Chesapeake Bay (Chesapeake Research Consortium, 1999~. They identified essential components of oyster restoration projects: construction of three-dimensional reefs, maintaining permanent sanctuary reefs, and selecting sites where natural spatfall will occur.
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From page 138... ...
Mann added that the direct harvest economic value of a fishery based on a restored resource will not reach historical levels unless there is an accompanying goal of long-term, self-sustaining community development. This argument prompted Mann to conclude that resource managers and relevant stakeholders and the ecology of Chesapeake Bay would be better served to view oyster restoration as the reestablishment of functional oyster reef communities, one of several cornerstones in the ecosystem.
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From page 139... ...
Successful restoration efforts provide a vehicle to educate the public and foster vested interest groups. Likewise, Coen and Luckenbach (2000)
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From page 140... ...
Balancing short-term fishery-driven interest with the need to establish long-term sustainable, ecologically functional oyster reefs poses a formidable resource management challenge. Since oyster reefs and oyster populations are essential elements in the estuarine ecosystem, oyster restoration should be viewed as a component in a holistic approach to applied resource management.
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From page 141... ...
The Aquaculture Genetics and Breeding Technology Center is testing disease-resistant strains to develop selected strains that are resistant to MSX and Dermo diseases and that can be ultimately used to produce disease-resistant seed for restoring oyster populations. Maryland and Virginia also participate in the Cooperative Regional Oyster Selective Breeding Project (CROSBreed)
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From page 142... ...
While restoration efforts have resulted in limited progress in establishing sustainable oyster populations, there remains an opinion among some researchers and resource managers that a more comprehensive management approach will ultimately lead to some level of oyster resource recovery. The approach would rely on applying a more stringent genetic improvement component based on newly emerging technologies, developing disease-resistant strains; selecting locations where environmental conditions are favorable for recruitment, growth, and survival; designing and constructing optimal reef habitat to encourage spat setting; avoiding disease, including growing oysters in areas or in a manner that reduces the chance of infection and not using infected seed; managing postrestoration populations for multiyear class distributions; and setting a long-term time frame (decade)
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From page 143... ...
The plan's objectives include: . increase oyster populations to levels that restore important ecological functions, habitat, and self-sustaining regional populations; · achieve a sustainable oyster fishery through a combination of harvest from public oyster grounds and private aquaculture; · reduce the impacts of disease on oyster populations; and · increase hatchery production and develop disease-resistant strains.
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From page 144... ...
T 1me It will take decades and possibly centuries to restore native oyster populations and oyster reefs.
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From page 145... ...
Eliminating harvests, enhancing substrates, and controlling habitat degradation are potential management strategies to increase oyster populations, population size distributions, reproductive potential, spawning, and recruitment. The draft COMP incorporates restoration components that establish management areas to protect extant brood stocks by prohibiting or restricting harvesting.
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From page 146... ...
The dominant source of shells for oyster restoration since 1960 has been dredged shells from buried shell deposits. The sources of dredged oyster shell for Maryland's repletion program are dwindling, and permits to dredge shell deposits from the upper bay may become more difficult to acquire.
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From page 147... ...
Most will have the environmental belief that the biggest threat to the bay ecosystem is poor water quality and that current restoration efforts are attempting, without much progress to date, to restore oyster populations to levels that will result in improved ecological conditions. What is also important to consider when evaluating current restoration efforts, in addition to the ecological and economic impacts, are the cultural perceptions and attitudes surrounding oyster restoration as a cultural-environmental activity in and of itself.
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From page 148... ...
However, it is also important to understand that restoring productive oyster reef habitat is only one part of a complex ecosystem, and resource managers and researchers must guard against the sentiment that oyster restoration can single-handedly resolve all of the ecological and environmental problems facing the bay. Successful restoration should result in a combination of positive effects that are inextricably linked and the synergy of these effects should be evaluated when determining the success of oyster restoration projects.
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From page 149... ...
A comprehensive management approach relies on applying a more stringent genetic improvement component to develop disease-resistant strains based on newly emerging technologies; selecting locations where environmental conditions are favorable for recruitment, growth, and survival; designing and constructing optimal reef habitat; avoiding disease, including growing oysters in areas or in a manner that reduces the chance of infection and not using infected seed; managing multiyear class distributions for sustainability; and providing a long-term time frame for success. Restoration efforts have cultural-environmental meaning in addition to ecological and economic benefits.
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