Abstract
Restoring and conserving coastal resilience faces increasing challenges under current climate change predictions. 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. 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 urban estuaries is motivated by the synergistic ecosystem benefits this native keystone species can deliver. 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. This study assessed fitness-related performance across the HRE salinity gradient to evaluate habitat suitability on an estuarine scale. Oysters were hatchery-produced from wild, moderate-salinity broodstock, then outplanted for measurement of growth, survival, reproduction and disease prevalence over two years. Survival was generally higher in the lower salinity river sites and in the higher salinity Jamaica Bay sites relative to mesohaline NYC harbor sites. Growth rate was highest in Jamaica Bay and had high variation among other sites. Surprisingly, the highest proportion of individuals with sex-differentiated gametes and the highest average gonad maturation index was found at a low salinity site. 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. 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.
Highlights
Estuarine 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 [1]
Before discussing the broader Hudson/Raritan Estuary (HRE) restoration potential afforded by this super-hero Tappan Zee–Haverstraw Bay region (TZ-HB) population, we critically examine these measures of oyster performance, identify caveats, and put them into context based on the literature
The historic oyster reef footprint of 18th century New York is never likely to be restored, but viability of the Hudson/Raritan Estuary oyster population depends on restoring some metapopulation structure
Summary
Estuarine 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 [1]. 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. Persuasive arguments for doing so have been made on the basis of economics, human well-being, biodiversity, and coupled human-ecological resilience [2,3]. 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. What’s possible in urban estuaries, and how best to accomplish population replenishment?
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
