Podcast: The Vital Role of Oysters in Galveston Bay's Ecosystem

What lies beneath the surface of Galveston Bay? Underneath the murky, brackish water? A vibrant ecosystem teeming with life, shrimp, brackish water fish, and, most notably, oysters.

Galveston Bay has been a historical haven for thriving oyster reefs. Before Europeans arrived in Texas, local Native American communities relied on oysters as a key food source. As settlers moved in in the early 1800s, oysters supported both the population and economy. Oyster reefs also played a crucial role in maintaining the balance of the bay's ecosystem.

Today, let's explore the eastern oyster, the Crassostrea Virginica, and learn how these small but powerful creatures help keep the bay healthy and how people work together to restore their struggling reefs.

Historically, oysters and clams were a convenient and important food source for coastal indigenous people. After harvesting and eating them, the shells would be tossed to designated trash piles. Archaeologists call these piles shell middens, and they can provide important information about local indigenous people, such as where they lived, what they ate, and even what the environment was like. The two oldest known shell middens on the Texas coast are located near Galveston Bay and date back as far as 3500 years. Older shell middens are thought to exist but are now buried under the water and sediment of coastal bays.

Texas is one of the few states that harvest oysters from natural beds instead of farming them in crates. For over 150 years, this unique oyster industry has been a thriving part of Galveston Bay's economy. Oysters are easy to collect by hand or with simple tools. As the commercial industry grew, oystermen developed special tools for harvesting. A dredge is essentially a large metal net that rakes the bottom of the reef or seafloor. Initially, sailboats were used to pull the dredges.

By 1885, Galveston's seasonal oyster industry provided jobs for 500 men and shipped oysters all over the southwest United States. As technology developed, boats were equipped with motors and winches. Refrigeration and other preservation methods developed in the early 1900s allowed people all over the country to enjoy oysters, and the industry boomed. So many of the reefs in Galveston Bay were dredged and dredged and dredged. Even after harvesting all the live oysters off the reefs. The old shells were dredged and used for construction.

During the early 20th century, mud shell, consisting of oyster shell, was recovered from the reefs buried under many feet of mud, and used for building roads, as well as a major component in shell based cement. Between 1912 and 1962, the oyster shell industry removed 214 million cubic yards from Texas shores. When constructing the Houston Astrodome in the early 1960s, over 500,000 cubic yards of oyster shells were used to construct the stadium and the parking lot.

For nearly a century, Galveston Bay oysters were over harvested and many living reefs were destroyed. By the 1980s, the oyster industry was threatened, and natural disasters like hurricanes put additional pressure on these reefs.

Today, the oyster reefs are struggling due to a legacy of overfishing, a practice that has significantly reduced the population of oysters in the bay. This, coupled with environmental challenges, has led to the decline of the reefs. But there is hope and a concerted effort to restore these reefs. Scientists, conservation groups, and communities around Galveston Bay are working together to restore this habitat.

Galveston Bay is home to the eastern oyster, the Crassostrea Virginica.

Oysters are a keystone species. They are critical in maintaining a healthy marine ecosystem. They help keep the bay clean, and oyster reefs provide important habitats for fish, crabs, and other aquatic life. The overall health of the bay depends on the health of these oyster reefs. Oysters are natural filter feeders, drawing in water through their gills and capturing microscopic plants and animals.

This process purifies the water, with each oyster capable of filtering up to 50 gallons a day. Simply put, the more oysters in the bay, the better quality of water we have. So how do oyster reefs grow? When oysters spawn, it's a numbers game. Females can release up to 100 million eggs. But only about 1 percent of fertilized eggs survive to the next stage.

Within a few hours of fertilization, the eggs grow tiny shells. They then develop into rice sized larvae and search for their permanent home for a few weeks. They eventually attach to a solid surface, such as rocks, piers, or ideally, existing reefs. In an oyster's perfect world, they'll stick themselves to their friends and family. Generations of oysters slowly build up to create a reef, essentially a mass congregation of oysters. The juvenile oysters, known as spat, or seed, grow quickly.

In Texas, it takes roughly 18 months to reach market size, which is around 3 inches. Market size is essentially how large the oysters have to be to serve, sell, or eat. If these oysters are left alone long enough, they have been known to live 20 years and reach 10 inches long. Underwater, the reefs provide a rich habitat for aquatic wildlife, such as crabs and fish. In Texas, they offer shelter and food for 303 different marine species. Reefs also offer extra protection against coastal erosion.

These reefs help stabilize sediments and reduce the impact of storm surges. providing a buffer that protects both natural and man made shorelines. These protected shorelines provide a safer environment for plants, animals, and people, especially in hurricane prone areas like the Gulf Coast of Texas. In September of 2008, the storm surge of Hurricane Ike left behind masses of debris and sediment that smothered and decimated oyster reefs. The Galveston Bay Foundation reported that 60 percent of the oyster habitat was lost as a result.

Oysters prefer clean, shallow, diluted seawater, and before the human population boomed in Texas over the past 200 years, Oysters flourished in the bays along the Texas coast. In the northern portion of Galveston Bay, there was an oyster shell reef called Redfish Bar. It became a hazard to maritime navigation, and in the early 1900s, while dredging a 50 mile long ship channel to the Port of Houston, Redfish Bar was dredged through, along with many other smaller oyster reefs.

Oyster reefs are one of the most threatened marine habitats on Earth. The Texas Parks and Wildlife Department works to monitor and maintain a healthy population at home. But as most things go, it's a fight to balance human demand with environmental sustainability. Fortunately, restoring these reefs and the oyster industry is not only possible, but considerable effort is being put forth right now.

The Galveston Bay Foundation. The Nature Conservancy, Texas Sea Grant, and private industry partners are working to rebuild the oyster habitat. After eating a few dozen oysters in a local restaurant, those restaurants can donate their discarded oyster shells to serve as a foundation for future reefs. The old shells are the perfect foundation for oyster larvae to settle and grow.

Private residents living on canals on the bayside of Galveston Island have even taken measures into their own hands. By dropping crates filled with old oyster shells, into the canals at their home, giving this oyster larva a place to find a home and begin to grow. There is even an effort underway to build up the crate farming oyster industry in Galveston Bay, helping to relieve the pressure on the reef ecosystems and diversify the fishing economy.

All of this effort is being put forth by non profit organizations, for profit industry partners, and private citizens to bring back the population of oysters in Galveston Bay and bays around the country.

As you take in the view of Galveston Bay, remember the critical role oysters play in keeping the ecosystem in balance. Through the efforts of conservationists, scientists, and the local community, the reefs are slowly being restored, ensuring Galveston Bay remains a vibrant habitat for marine life.