Brevard Zoo’s ‘Restore Our Shores’ Team Introduces New Gabion Cages Which Simulate Natural Oyster Reefs
By Brevard Zoo // August 31, 2020
Gabions are cages made of galvanized steel that can hold around 30 pounds of oyster shell
BREVARD COUNTY, FLORIDA – The Brevard Zoo Restore Our Shores team is constantly working to improve the Indian River Lagoon, whether that’s through constructing oyster reefs, planting mangroves or spreading awareness in the community.
“We are always looking for ways to make our programs more streamlined, more sustainable and more effective, so when an opportunity arises to improve our techniques—like testing out a new material—we jump on it,” said Brevard Zoo officials.
Gabions are cages made of galvanized steel that can hold around 30 pounds of oyster shell.
Although they have never used this material before, gabions are frequently employed in large-scale civil engineering projects around the world.
These cages are a plastic-free alternative to the industry-standard mesh bags we currently use to contain oyster shells, and they have larger holes that may offer better water circulation—which is great for live oysters.
Once the gabions are hand-built by our staff and volunteers, they will each be filled with 30 pounds of oyster shell as a “base” layer, and then handfuls of live oysters will be added to the top of each cage before they are placed in the lagoon.
These “shell cages” simulate natural oyster reefs, which are made up of mostly dead shell with live oysters clustered on top. Simply dumping oysters into the lagoon would not work because these bivalves need relief off the bottom to access enough oxygen.
By containing the mixture of oysters within the gabions, we are not only mimicking their natural habitat but also ensuring that they are not dispersed by wave action—which is not conducive to oyster growth and recruitment.
“While we are very excited to try out these new materials, it is important to note that they are being used in an experimental capacity,” said zoo officials.
We are using 1,600 of these devices to build a 320-foot-long test reef off the shores of Merritt Island, where the cages will be monitored for durability, algae growth and oyster recruitment in comparison to the plastic bags.
To learn more about how Brevard Zoo is helping the lagoon and ways you can get involved, check out the Restore Our Shores website.