Climate Local Now: Let’s All Be More Like Oysters - East End Beacon
It can be hard to get excited about something that just looks like rocks. I often say this when presenting educational curricula or leading a Stewardship Session. But once you learn more about our native oyster, I promise you will have a new appreciation for this incredibly well-adapted animal.
Celebrating Oysters and their Reefs
I’m not the only one who touts their love of oysters – they are widely celebrated for their impressive water-filtering ability, as well as being a prized tasty treat.
The aspect of oysters that I love, though, is the way they grow in the wild; building off of each other, forming clusters that offer shelter to a wonderful variety of other marine fauna and flora. For this reason, oysters are considered a “keystone species.” In architecture, a keystone is the critical piece placed at the apex of an arch that supports the structure at large. In our bays, oyster reefs provide services essential to the health and function of the marine ecosystem.
Through their feeding on phytoplankton, oysters help keep algae blooms in check and increase the amount of light extending through the water column, which is necessary for the proliferation of eelgrass meadows.
The eelgrass in turn sequesters CO2 and oxygenates the water for the oysters and the menagerie of commercially and recreationally important marine species – bivalves, crustaceans, and finfish – that are embedded in the economy and culture of the East End.
These other species rely on the reefs as their habitat for protection from predators, as a source for food, or mating grounds, and thus contributing to species diversity within the ecosystem. Think of images of coral reefs you may have seen – jagged, rolling formations with all different animals, from shrimp to sharks, swimming in and around them and interacting together. Oyster reefs are very similar, just not as colorful. In many of the places where coral reefs do not grow, oyster reefs fill that niche.
Our Gregarious, Resilient Native
From the cold saline waters of Eastern Canada to the brackish mud flats of the Gulf of Mexico, there is just one native species of oyster – Crassostrea virginica. Their environment forms them. They look different, taste different, but they are the same animal.
It speaks to their resiliency to be able to thrive in such variable climates and conditions, growing and replenishing themselves, becoming the integral reef habitat that supports their ecosystem.
In the late spring, as the waters warm, the oysters receive their signal to spawn. The females broadcast grainy plumes of eggs and the males release their sperm. After fertilization, the resulting swimming larvae will eventually begin to settle. They are gregarious in nature, seeking the shells of other oysters onto which they will attach and grow. They know – most likely through chemical cues – that where other adult oysters are growing signifies success and survival. Over time, the juveniles outcompete the older ones, each generation supporting the next in the formation of the reef structure.
Restoration is My Passion
Oyster reefs once dominated our coast, but overharvesting and pollution through industrialization and development has led to a dramatic decrease in their population. Working to restore them has become a passion and a primary effort for me through Cornell Cooperative Extension’s Back to the Bays initiative.
Collecting empty shells from restaurants and oyster farms is the first step, which removes large volumes of useable material from the waste stream to eventually serve as the setting substrate for our hatchery-raised oyster larvae. Once they make the clean cured shells their new home, the juvenile oysters – now called “spat-on-shell” – are distributed to our designated Stewardship Sites to begin growing into reefs.
But it’s not just about habitat restoration; in everything the Back to the Bays team does, we keep education and hands-on engagement at the core. Our growing base of volunteer Stewards helps us plant the spat-on-shell, weave eelgrass shoots, or collect marsh grass seeds. Involving our communities in our work helps people better understand these species, as well as value their own connection to, and role in, our marine ecosystem.
As we flow into 2026, let’s ask ourselves how we can all be more like those oysters – coming together and supporting those around us, cultivating diversity in our community, and remaining resilient in our changing environment.
Kate Rossi-Snook holds a Bachelors in Marine Biology and Masters in Environmental Anthropology, and has been working in shellfish aquaculture, habitat restoration and water quality improvement for over 20 years. She lives on Shelter Island with her husband (Tim), son (Oscar), and dog (Jolene), and is most happy being outside, enjoying good food, and spending time with her friends. She can be reached at kr474@cornell.edu