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Oyster Research and Restoration


Oysters were once a very abundant and cherished resource of the Harbor estuary, but by the early 20th century, sediment and water pollution and overharvesting had all but eliminated these once dominant creatures. While only a few small patches of oyster reef remain today, water and sediment quality has dramatically improved, making the restoration of the Eastern oyster (Crassostrea virginica) to NY Harbor now potentially possible.

For the past decade, the Hudson River Foundation has worked with partners to study, design, and implement oyster restoration techniques suitable for the diverse environs of the Harbor Estuary. Starting with small research pilot projects in 2010, the Hudson River Foundation and our partners have now expanded to multiple acres restoration projects. 

The Governor Mario M. Cuomo/New NY Bridge Project at Tappan Zee

    Partners: The Hudson River Foundation, the University of New Hampshire, Billion Oyster Project under the direction of AKRF, Inc.
    The Tappan Zee project represents the most successful oyster reef restoration project implemented in the Hudson River Estuary. The project exceeded all previous projects in terms of restored area and several metrics of early restoration success. Due to the location of the Tappan Zee Bridge near the northern limit of oysters in the Hudson River, successful oyster restoration in this area depended on careful consideration of habitat parameters affecting oyster settlement, survival, and growth which informed the selection of specific restoration techniques and locations. Based on October 2020 sampling results at the close of this study, an estimated total of 5.8 million live oysters had colonized the deployed substrates at the project sites. The new reef communities also provided substantial new habitat for other species, including benthic organisms, resident and transient fish, and additional filter feeding species (mussels and barnacles) which also contribute to improving water quality. As this study and the previous 3-year pilot study have demonstrated, the conditions at Tappan Zee are suitable for large scale oyster restoration projects to be highly successful.

Governor Mario M. Cuomo/New NY Bridge Pilot Project at Tappan Zee

Partners: The Hudson River Foundation, the University of New Hampshire, Billion Oyster Project under the direction of AKRF, Inc.

The Tappan Zee Bridge oyster mitigation project was preceded by a 3-year pilot study. This study assessed the performance of three potential restoration substrates, 1) metal gabion cages containing oyster shells, 2) small Reef Balls (“Lo-Pro”), and 3) larger Reef Balls (“mini-bay ball” style), at several potential restoration sites. Performance metrics included oyster recruitment (attachment of oyster to substrates), oyster growth and survival, and the longevity and sustainability of the two different substrate construction techniques. The pilot study determined that Mini-Bay reef balls and shell-filled gabions provided effective substrates, and were chosen for the full-scale reef restoration efforts.

Location of the three oyster reef mitigation sites and deployment of two substrate types in July 2018

For more information on our current projects see below: