Recently, I joined other volunteers on a project to place oyster domes along a small mangrove island, Little Bird Key. I signed up at the suggestion of a friend, but I didn’t understand or realize the purpose.

We started the cold, windy morning at the Fort DeSoto State Park boat dock, just outside of St. Petersburg, Florida. The group was mobilized by the Tampa Bay Watch team, and we began to transfer the oyster domes from the trailer to the boats: two skiffs and a small barge. The oyster domes are approximately 200 pounds, thus there were several methods to transfer the domes. First, was people power. A steel bar slid through the dome holes requiring two people to carry and lift the domes into the skiffs. Secondly, dollies were used to get the domes close to the watercraft with two people making the transfer to the boat. Lastly, in order to load the barge, a small crane was used. With all the volunteers, and good instruction, the domes were quickly loaded. 

Oyster Domes on the Tampa Bay Watch trailer, ready to be loaded on the boats.

We were separated into groups, one to take the trailer back to the organization’s office to load more domes onto the trailer, and another with the boats to place the domes at Little Bird Key. I went with the placement group. I had to….it involved a boat ride!

So, what’s the purpose of the oyster domes? This project’s goal is to protect the shoreline of the small mangrove island. The oyster habitat is a beneficial byproduct. Natural erosion of the coastline occurs from tide and wave patterns and movement. However, this island experiences a higher level of erosion from the heavy boat traffic traveling through the nearby channel. The erosion harms the mangrove trees because the sand provides the earth base for the trees by surrounding and supporting the mangrove tree roots. The trees also gains its nutrition via its roots. As the sand erodes, the support and food source are removed for the tree and they die. Furthermore, without the trees and roots holding the sand in place, erosion is expedited.

Erosion has begun to expose the roots of these mangrove trees.

The oyster domes are circular dome shaped structures made of concrete. They have several holes in the structure, which allow fish and other sea creatures to swim in and out of and may provide protection from larger fish or predators. The oyster domes were made by the Tampa Bay Watch employees and volunteers. Concrete marine-friendly aggregate materials are used and poured into the dome casts, then allowed to dry and set. It took several gatherings of workers and volunteers several weeks in order to make the number of domes required for this project. 

Oyester Domes placed on the beach during low tide.

At the beach site, the domes are placed next to each other, providing a lined barrier. There are openings placed every so many feet, allowing larger sea animals, like manatee, an outlet if they find themselves behind the dome.

So why are the mangroves important? This particular mangrove island is a bird nesting area. Without the trees, the birds lose an important area to safely lay eggs and raise their chicks during nesting season. While we were working, an early nesting blue heron had already set up a nest just inside the tree line. Herons usually nest in March or April.

Early nesting blue heron.

The mangroves also provide an ecosystem for other sea life nesting and hatching. Many fish spawn and lay eggs along the mangroves. On this day, we found several starfish and jellyfish along the shore, and several groups of dolphins swam by.

What about the oysters? The domes will provide an environment for the oysters, which play an important role in acting as natural water filters. The oysters filter pollutants, such as nitrogen and phosphorus, from the gulf water. An oyster can filter between 2 and 10 gallons of water an hour. Their work helps provide clearer and less polluted waters.

Starfish located while waiting for more oyster domes to be delivered.

The project was funded to protect the shoreline from erosion, but the impacts are far great as it provides a habitat for birds, fish, oysters, and other saline which the bay counts on to remain a viable ecosystem.

Much like the circular shape of the domes, the ecosystem is circular, in that one things depends on another for it’s continued survival.

So where are your charity and volunteer interests? Take a moment to consider the broader and larger impact that your time and/or money can provide to the charity or cause of your passion. It’s a new year and new decade, find ways to make your positive contribution.

Find your venture.

Gary Gresham

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