Studying What Oysters Need to Thrive in Polluted Urban Waterways
By LIDA TUNESI
Eastern oysters were once an important part of the ecosystem of the Hudson-Raritan Estuary—the area where the tidal rivers meet the sea—but pollution and overharvesting have greatly lowered their numbers. A new study looked at how water quality and other conditions in rivers affect oysters’ reproductive health. The findings could help inform restoration efforts.
It’s important for people working on restoration projects to consider reproductive health if they want the oysters to continue producing new generations, the authors explained.
Allison Mass Fitzgerald, who completed her Ph.D. at The Graduate Center, led the study, which appears in Marine Environmental Research. Professors William Wallace (College of Staten Island, GC) and Chester Zarnoch (Baruch College, GC) were also co-authors. Fitzgerald now teaches at New Jersey City University.
The scientists studied oysters that they transplanted to two places—Soundview Park in the Bronx, where the Bronx River meets the East River, and a site in the Great Bay in Tuckerton, New Jersey. Soundview Park let them study the effects of a degraded environment while the Great Bay functioned as the “reference” site.
Over one year, the team monitored the oysters. The oysters at Soundview Park had lower levels of Vitellogenin-like proteins. Scientists use these proteins, which are precursors to the oysters’ egg yolks, as a measure of reproductive capacity. Higher protein levels indicate better chances of spawning the next generation of oysters. They also found that the oysters in the Bronx had higher cadmium levels and lower condition index, a measure of general health, than the oysters in New Jersey.
“The results showed that adult oysters in highly urbanized environments may be challenged by both metals and poor water quality,” the authors wrote, “which may play a role in influencing oyster condition and reproductive potential.”