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A critical precursor to restoration has been to establish secure man-
agement to prevent degradation or loss of restored areas. This has
been achieved though the establishment of legal sanctuaries, and
through private ownership or leasing of intertidal and subtidal lands.
A broad range of restoration techniques have been developed and
tested. Where recovery is limited by habitat availability (young oyster
“spat” need to settle on hard substrates), restoration techniques fo-
cus on the provision of “cultch”, or areas of hard bottom. Elsewhere,
where recruitment is a limiting factor, juveniles need to be returned to
the environment. In both cases experimental work has identified the
importance of vertical relief, hydrodynamics, and a wider understand-
ing of meta-populations in restoring reefs to levels that are self-sus-
taining and ecologically significant. Systematic approaches, based on
the best science, are leading to successful restoration across the
country, such as the restoration by the US Army Corps of Engineers
of over 297ha of oyster reef since 2001 within the Chesapeake Bay,
North America’s largest estuary. Increasingly ambitious programs
are being established; the recent Chesapeake Bay Executive Order
(2009) resulted in the goal of restoring oyster populations in 20 of
35–40 candidate tributaries of the Chesapeake by 2025. This is an
immense challenge given that oyster reefs were close to ecologi-
cal extinction in this Bay just a few years ago.
Source: Philine zu Ermgassen and Mark Spalding, The Nature Conservancy
and Cambridge University, Personal communication, 2010.
Photo credits: Mark Spalding.
benefits of successful oyster restoration on the Eastern Shore.
Along the South Eastern United States, fin-fish and decapod
fisheries benefits derived from restored oyster reefs have been
estimated at 2.6kg/10m
2
/year, while in Louisiana and North
Carolina restored intertidal reefs have locally reduced the rate
of shoreline retreat. Work is in process to determine how such
benefits may vary between locations.
The success of projects such as those on the Eastern Shore
of Virginia provided a major impetus for encouraging the US
government to provide USD 150 million in a 2009 national
stimulus package for large-scale restoration projects, includ-
ing several other oyster reef projects. More science is needed,
notably to gain a better understanding of the final targets for
restoration. How much restoration will be needed to achieve
measurable and useful levels of water purification or increased
fisheries production? Where and how should reefs be arrayed
to maximize coastal protection benefits? Enough is already
known, however, for the work to commence, and the research
is running in parallel, enabling benefits to be derived even as
understanding of the complex ecological story is refined.