Oyster Reefs
Building Oyster Reefs
Historically, oysters were highly abundant in New York waters, from the Hudson River and New York Harbor to the Long Island Sound and south shore bays. Overharvesting and pollution resulted in vast declines of this shellfish and the elimination of oyster reefs that once populated coastal waters. Part of the ShiRP approach was to re-establish oyster reefs in the western part of the bay, to enhance our shellfish restoration efforts, increase filtration, and provide complex three-dimensional habitat for other organisms in the bay.
In nature, oysters are broadcast spawners – meaning that eggs and sperm are released into the water column where fertilization occurs. After floating for a short time, oyster larvae seek a hard substrate on which to settle. Once oyster larvae permanently attach to a surface, they are known as spat. We use a “spat-on-shell” approach to create oyster reefs, mimicking how reefs would form naturally in the wild.
Establishing spat-on-shell
In the laboratory, ShiRP places mesh bags filled with bare clam, oyster, and scallop shell into large 500 gallon tubs, combined with seawater filled with oyster larvae. During a period of time where conditions are meticulously checked and regulated, the larvae settle upon the surfaces and crevices within the shell bags. Once spat-on-shell is established, our researchers use quadrats to measure spat and estimate average oyster density per shell bag, and to record sizes prior to deployment into the field. Spat start out smaller than the size of a poppy seed but can end up growing larger than a foot!
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When the shell bags are ready, they are transported via SBU Research Vessels to the reef site and then placed via a pre-configured design into the open waters of Shinnecock Bay. Here, they become “living walls” of the reef structure. The reef design is analogous to a raised garden bed, where living walls act as a corral within which loose oysters and spat on shell can be planted over time.
All of our reefs including the interior are constructed on base layer of shell that provides stability and prevents any sinking of the “living” shell bags into the sediment. The shell base within the interior of the reef also provides necessary substrate that is needed once adult oysters begin reproducing.
Our first reefs were installed in 2018, and we have been building upon them annually. They are growing in both size and biodiversity, and are providing needed filtration and habitat, in western Shinnecock Bay.
First of its kind..
As was the case for the clam sanctuary site selection, the areas for pilot-scale oyster reefs were identified using science-based criteria including growth and mortality measurements, depth, salinity, bottom type, and proximity to navigable waters frequented by boaters. In 2017, the New York State Department of Environmental Conservation permitted installation of oyster reefs, the first on Long Island, based on an application providing extensive research, planning, and justification.
The Results...
Four
oyster reefs built since 2018
5 million
oyster spat on shell deployed into the Western bay
Strong
vertical growth of the oysters
Monitoring
Our oyster reefs are monitored in several ways. As we install the shell bags when building the reefs, we create and label smaller monitoring bags so that we an measure growth and survivorship.
What are we monitoring?
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Oyster growth
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Presence of diseases such as Dermo
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New Recruitment – is there evidence of natural reproduction
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Water quality changes
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Community settlement and increased biodiversity
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