Conservation // 3 min Read

Oyster Ecology

Written by Palmetto Bluff

Oct 24, 2019

Pop! Click! Snap! A din rings across the marsh from oysters closing their shells, jets of water springing from sealing halves, as water recedes from the intertidal zone.

Eastern oysters (Crassostrea virginica), probably known best for their central role in autumnal oyster roasts, are a keystone species in our coastal marshes and provide essential ecosystem functions including erosion control, water filtration, and habitat creation.

Oyster reefs are barriers that break down waves from hurricanes before they hit the mainland, retaining the substrate of our shorelines. Foraging primarily on microscopic phytoplankton, oysters are filter feeders and can filter up to 4 gallons of water per hour. They can even remove pollutants, including heavy metals such as mercury, providing a cleaning service through their foraging activities.

Over 300 species of plants and animals rely on oysters for survival. Oyster reefs provide three-dimensional structures for fish, crabs, shrimp, and other invertebrates on the otherwise fl at bottom of creeks and estuaries. Declines in oyster populations create a trophic cascade of loss, depleting the abundance and diversity of species present throughout the food chain.

In addition to providing habitat, oysters themselves have specific habitat requirements. Ninety-five percent of eastern oysters live in the intertidal zone, the space within tidal creeks covered during high tide and exposed during low tide. If oysters are too deep, they are unable to compete with more benthic species such as boring sponges. If oysters are too shallow, they reduce the amount of time they can spend feeding. The intertidal zone provides important advantages for oysters, and the success of restored reefs depends on specific placement within this zone.

The oyster life cycle is surprisingly complex. Spawning begins in April when adults broadcast sperm and eggs into the water column, peaks during the summer, and continues into October. During this period, 50 percent of the tissue within the oysters is comprised of gonads—the organs that produce eggs and sperm. Resulting larvae have poor locomotory skills and rely on tides for transport, spending their first two weeks floating with currents while developing into more complex larval stages. Around two weeks old, they form their final larval stage and begin to sink to the creek bottom. This final stage is different from previous ones in that the larva has a “foot” that allows it to be somewhat mobile, crawling over the creek bottom in search of a sustainable place to permanently rest.

Oyster larvae need hard substrates to which they can attach, preferring the shells of other oysters—both alive and dead. Once the larva finds a substrate, it permanently cements itself to that location and metamorphizes into a small version of its adult form. It grows rapidly, becoming mature in two to three years. Eastern oysters are protandrous hermaphrodites, maturing first as males and transitioning to females when they are older and larger.

Females can produce more than 100 million eggs in a single year—with the waters along coastal South Carolina filled with oyster larvae during the summer months. Unfortunately, this same water lacks an abundance of substrate to which larvae can attach. Over-harvesting and habitat loss—including the depletion of oyster shell substrate—have contributed to significant declines in oyster populations. Less than 20 percent of historic oyster reefs currently exist along U.S. coastlines.

Fortunately, there is something we can all do to help. The South Carolina Department of Natural Resources oversees the South Carolina Oyster Restoration and Enhancement (SCORE) program, which obtains oyster shells from citizens through shell drop-off centers, then quarantines and recycles them through the creation of new reefs.

To learn more about SCORE, visit


Food & Wine / Fall Recipes From Buffalos

Your Pine-ness Cocktail Recipe Before delving into the ingredients and recipe for Buffalos’ delectable Ricotta Meatballs and Sauce, it is imperative that the chef has an excellent cocktail for cooking. Pairing the sweetness of pineapple with the woody flavo...

Sep 2023
palmetto bluff neighborhoods

Real Estate / Waterfront Neighborhoods in Palmetto Bluff

Coastal Palmetto Bluff Neighborhoods Palmetto Bluff, a private community nestled along the South Carolina coastline, presents a harmonious blend of luxurious living, recreational spaces, and a vibrant atmosphere. The meticulously designed Palmetto Bluff neigh...

Sep 2023
wilson landing

Waterways / Behind the Bluff with Marina Captain: Thomas Shanahan

Meet Captain Tom of Palmetto Bluff’s Wilson Landing  In the tranquil embrace of Bluffton's Lowcountry, where rivers wind their way through nature's masterpiece, an extraordinary tale unfolds at Wilson Landing of Palmetto Bluff. The story belongs to Captain Th...

Sep 2023
luxury kitchen design

Architecture & Design / Designing the Southern Kitchen of Your Dreams

Your Guide to a Luxury Kitchen Design The kitchen has long been the heart of the home, where cherished memories are cooked up and shared. When it comes to Lowcountry living, a well-designed kitchen is not just a place to prepare meals but a space that encapsu...

Sep 2023
summer bucket list

Culture / Summer Activities to Check Off Your List Before the Fall

10 Activities You Have to Cross Off Your Summer Bucket List While the days are long and the sun hangs high in the sky, summer offers a golden opportunity to create lasting memories and partake in a variety of thrilling activities. Before the cooler breeze of ...

Sep 2023

Conservation / Water Way

Palmetto Bluff is an ecological wonderland, with its maritime forest and tidal rivers, its salt marsh and abundant wildlife. But perhaps one of the most unique features of this wedge of Lowcountry is the impressive inland waterway that wends through the landsc...

Aug 2023

Artist in Residence / Places Around Palmetto Bluff to Paint Plein Air

Plein Air Painting and Our August Artist in Residence Palmetto Bluff is a paradise for art enthusiasts and nature lovers alike with its breathtaking landscapes, diverse ecosystems, and serene atmosphere. With that being said, the Bluff is the perfect canvas f...

Aug 2023
coastal living

Waterways / Experience Health and Happiness By Living on the Coast

5 Health Benefits of Coastal Living Did you know that life by the coast is not only the most idyllic way to live, but it also improves your health? All in all, coastal living is a rejuvenating experience for the mind, body, and soul. From the cool, salty bree...

Aug 2023
south carolina lowcountry

Culture / 9 Enticing Facts About the Lowcountry

Discover the Charm of the South Carolina Lowcountry Where history and nature intertwine with effortless grace, the South Carolina Lowcountry is a region that allures visitors and residents alike with its timeless beauty, enchanting landscapes, and diverse cul...

Aug 2023

Conservation / Behind the Bluff with Palmetto Bluff Conservancy Educator: Aaron Palmieri

Aaron’s Journey to the Palmetto Bluff Conservancy   In the heart of the Lowcountry, where lush landscapes and diverse ecosystems flourish, lies a hidden gem known as Palmetto Bluff. This breathtaking sanctuary serves as a haven for an array of wildlife, offer...

Aug 2023
Community Villages
Palmetto Bluff Club
On The Water
The Arts Initiative
About Us