Although NYC is the historical home of the eastern oysters’ rise to culinary fame, largely based on local HRE oyster stocks during the colonial period, now this native species ( Crassostrea virginica (Gmelin)) is nearly extirpated from the HRE. One of eleven ecosystem services prioritized for targeted restoration in the HRE is a sustainable oyster population because this keystone species has been shown to clarify the water through filter feeding, cycle nutrients from the water column to the benthos, provide habitat for hundreds of other species by building continually accreting reefs, and their reefs can help attenuate storm surge. Interest in the restoration of ecosystem services has been increasing as indicators of water quality have slowly improved since the 1972 passage of the Clean Water Act. For these reasons, and because Hurricane Sandy recently highlighted critical vulnerabilities, it is an urban estuary restoration case study of substantial importance and attracting great interest. It was among the first megacities in the world (10 million people ) and now hosts one of Earth’s greatest concentrations of human habitation and economic activity. New York City (NYC) grew over centuries from a colony enjoying one of the largest and most productive temperate estuaries in the world, the Hudson/Raritan Estuary (HRE).
What’s possible in urban estuaries, and how best to accomplish population replenishment? Nonetheless, contemplating this objective is daunting given the seemingly faint ecological heart-beat of these systems, the extensive hardening of shorelines, and the possibly high costs compared with less degraded estuaries. Persuasive arguments for doing so have been made on the basis of economics, human well-being, biodiversity, and coupled human-ecological resilience. more to lose, in these estuaries and it could be argued on that basis that there is a moral imperative to restore the ecosystem functions of these urban estuaries, first and foremost. It is likely that humans preferentially colonized the biotically richest estuaries where the natural capital helped support the prosperity and growth of modern coastal cities.
These results suggest that the remnant HRE oyster population is a robust, self-sustaining population that can be leveraged to support restoration of subpopulations in other parts of the estuary, but further research is required to determine if the mesohaline and near-ocean reaches of the HRE can support the full oyster life cycle.Įstuarine ecosystems are transition zones that provide essential habitat to hundreds of species, yet rank among the most heavily human-impacted ecosystems because of concentrated urbanization and increased impervious surface. Consistent with the advanced gametogenesis measured in experimental animals at low salinity, annual wild recruitment was documented near the low salinity remnant population in each of five monitored years. Surprisingly, the highest proportion of individuals with sex-differentiated gametes and the highest average gonad maturation index was found at a low salinity site. Growth rate was highest in Jamaica Bay and had high variation among other sites. Survival was generally higher in the lower salinity river sites and in the higher salinity Jamaica Bay sites relative to mesohaline NYC harbor sites. Oysters were hatchery-produced from wild, moderate-salinity broodstock, then outplanted for measurement of growth, survival, reproduction and disease prevalence over two years. This study assessed fitness-related performance across the HRE salinity gradient to evaluate habitat suitability on an estuarine scale. Recent surveys have documented substantial remnant populations of adult oysters in the upper low salinity zone of the Hudson/Raritan Estuary (HRE) near Tarrytown, NY. Oyster restoration in urban estuaries is motivated by the synergistic ecosystem benefits this native keystone species can deliver. New York City (NYC) coastal waters, once home to a booming oyster fishery for eastern oysters ( Crassostrea virginica), are now nearly devoid of live oyster reefs. Oyster restoration, in particular, faces threats from alterations in precipitation, warming water temperatures, and urbanization of coastlines that dramatically change salinity patterns, foster the proliferation and spread disease, and disrupt habitat connectivity, respectively.
Restoring and conserving coastal resilience faces increasing challenges under current climate change predictions.