Vertical oyster gardens improve local ecosystems and water quality, expert says
The ecosystem-improvement plan makes use of discarded oyster shells and unused space below docks.
| 3:40 p.m. July 22, 2022
The oyster shells previously sitting on your dinner plate at one of your favorite seafood restaurants are likely now strung together as part of a vertical oyster garden designed to help improve Sarasota Bay water quality.
A vertical oyster garden is made of recycled oyster shells and suspended from beneath docks to create a hard substrate in which juvenile oysters can attach and develop.
“There’s a lot of interest in creating artificial reefs under docks because it's an unused space,” said Shaun Swartz, an environmental specialist at Manatee County's Natural Resources department. “These are an alternative to some of the ones that are plastic-based and don’t last as long.”
The new initiative was created in order to improve the area’s marine ecosystems.
“Clams and oysters filter water through just by living in the waterway,” he said. “They’re filter feeders. They can remove nutrients from the water and increase water quality and clarity so much that you can get sea grasses and mangroves growing.”
Oysters can filter up to 50 gallons of water a day, which can aid in the growing concern of locals regarding the future of the area’s water quality, Swartz said.
“(Oysters) are the superheroes of this ecosystem,” Swartz said while participating in a Longboat Key “Talk of the Town” segment.
In the segment with Town Manager Tom Harmer, he illustrated the importance and benefits of the oyster shells in hopes of increasing community awareness of the program and encouraging participation.
Manatee County and the town of Longboat Key have partnered with Tampa Bay Estuary Program, Sarasota Estuary Program and Solutions To Avoid Red Tide as they begin dispersing the oyster gardens to residents with docks as part of a recent initiative to improve local ecosystems.
The shells that are part of the gardens are quarantined for about six months before being strung up with other shells, allowing for the removal of harmful bacteria and foodborne illness that the shells might have been exposed to after being prepared and consumed at the restaurants.
“It’s basically taking what would otherwise be trash at our landfill and creating something out of it,” Swartz said.
About 12 restaurants work with the county and its partners to recycle used shells.
The oyster shells are strung together by volunteers who drill small holes in the shells before stringing the twine, which has stainless steel wire in its middle, through the holes. The wire aids in ensuring the garden has a strong hold under the dock.
Swartz also takes piles of shells to local schools for the students to string up the oysters and learn about oysters and shellfish restoration.
Residents of the county and surrounding areas have the opportunity to pick up their own pre-made vertical oyster gardens for free at a drop box at the Robinson Preserve.
At the moment, the preserve drop box is the only location locals can pick up their vertical oyster gardens, but Swartz and the department are looking into ways to expand for easier access for the rest of the county.
The drop box can only store between 10 and 15 vertical oyster gardens at once. However, interest in upwards of 200 oyster gardens has been brought to Swartz, who has helped coordinate getting the shells to the homes.
Individuals who are interested in utilizing the drop box must fill out a survey using a QR code on the sign by the box to receive the code needed to open the lock.
The survey asks the resident if they are willing to participate in a citizen science monitoring effort. The effort is still in the works, but Swartz said the goal is to gather data about the oyster gardens and their progress through pictures and questions answered by participants.
Word-of-mouth and easy accessibility to the free product has aided in public interest in the initiative. Swartz cited that he has yet to come across someone that was opposed to the idea.
While this initiative is newer, the concept is not new to Swartz or the department. Vertical oyster gardens have been deployed before with some under fishing docks at the preserve for over a year.
“(The program) engages the community, gets them involved and then raises awareness about oyster restoration on a larger scale,” he said.
It takes anywhere from six week to six months for life to establish itself on the shells tied under docks.
Within six weeks, it is typical to see barnacles, marine worms and crabs staying on the shells. The juvenile oyster growth takes longer.
“When you have a space for little slimy creatures like crabs and worms and juvenile fish to live, it attracts other things in the food web,” Swartz said. “It’s creating prey and space for that prey, so that larger fish can come in and eat. It’s supporting larger wildlife in the area.”
The project is estimated to continue for the long-term with hopes of continuous community support to ensure optimal success.
“This community-based approach is pretty unique, especially a local government reaching across county lines and organizational boundaries,” he said. “To the best of my knowledge, I don’t know of anyone else doing it like this.”
One of the most recent deployments of the oyster gardens was at Longboat Key's Joan Durante Park. Swartz tied 50 strings of oyster shells to the bottom of scenic-overlook platforms along the park's waterfront boardwalk.
“It is unlikely you will see any growth on those yet as they have only been under there a couple of weeks,” he said.
Although the shells need to remain underwater at all times, some of the oyster gardens will be easily viewable by the public.
The proposed solution for improved water quality and ecosystem sustainability was chosen for its durability and lasting impacts on the ecosystem.
“Once they’re set up they are virtually maintenance-free,” Swartz said. “I always go back and check on them just to make sure they’re doing OK and to monitor growth and establishment. They’re really easy to get involved with and they don’t require a lot of maintenance.”