PREP Reports & Publications


The eastern oyster (Crassostrea virginica) in New Hampshire’s Great Bay Estuary has declined in the past decades, with local populations reduced due primarily to disease, excessive siltation, and past over-harvest. The loss of filtering oysters results in diminished ecological benefits for water quality, nitrogen control, and other services that healthy oyster populations provide. In support of management objectives to restore oyster populations, The Nature Conservancy (TNC) and the University of New Hampshire (UNH) have combined for a fifth consecutive year of scaled-up methods to rebuild oyster reefs and populations. Since 2009, we have “planted” seasoned shell, primarily surf-clam and oyster mix, on channel bottom as a hard substrate foundation to recruit spawn from nearby native populations. Constructed areas are amended to supplement recruitment with laboratory-raised and volunteer-grown “spat-on-shell” from remotely set larvae. Following four consecutive years of experience and adaptation, 2013 was a year of unprecedented effort and conservation outcomes. We successfully constructed and seeded five new acres of reef adjacent to native oysters in the Piscataqua River in Dover (1.5 acres) and in the Lamprey River in Newmarket (3.5 acres). Notably, we employed a new shell deployment method to achieve large-scale reef construction. Restoration efforts were greatly enhanced by excellent remote set success and outstanding natural recruitment, resulting in over 2M oysters. In addition, community engagement through the volunteer Oyster Conservationist program reached another all-time high with fifty families producing our largest oyster stock ever for restoration. Over the past five years, our efforts have added over 13 acres and 3M oysters to the ecosystem, increasing native Great Bay Estuary oyster populations by about 10%.


Piscataqua Region Estuaries Partnership

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Piscataqua Region Estuaries Partnership, Durham, NH

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