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Oysters, nature’s filter, may be key to saving Biscayne Bay

Miami native is collecting shells for a cause — and he needs your help

The keystone species is urgently being restored up and down Florida’s coast as climate change and pollution threaten our planet and way of life. And a community is coming together to bring back the lost oysters of Biscayne Bay.

MIAMI – On a Sunday morning in October, a group of South Florida residents of varying ages gathered at Kennedy Park in Coconut Grove for a citizen science project.

About 30,000 oyster shells have been collected from Michael’s Genuine and Kush restaurants, and they may play a key role in saving Biscayne Bay

“We’ve been collecting these since January,” said Tico Aran, founder of Watershed Action Lab. “And this is what we’re going to be using to make the oyster lines.”

Seafood lovers may find oysters a delicacy, but did you know they also play a vital role in protecting our coastlines from hurricane storm surge and clean pollution from our waterways?

The keystone species is urgently being restored up and down Florida’s coast as climate change and pollution threaten our planet and way of life. And a community is coming together to bring back the lost oysters of Biscayne Bay.

“When people hear that Biscayne Bay is dying, it seems like too big of a problem and it’s someone else’s job to take care of,” Aran said. “So how can we kind of ask ourselves what can we do?”

Aran, a Miami native, is not waiting for the cavalry. Shaken by last summer’s devastating fish kill in the bay — triggered by a sudden oxygen drop from massive loss of seagrasses due to decades of pollution flowing into the watershed — Aran was driven to find a solution, and he thinks he found it under the dock of his family home in Old Cutler Bay.

“We saw the shells outside but we didn’t know what they were,” he said. “So my dad said, ‘Hey, if you really want to clean the bay, these oyster shells are the key.’”

Oysters are nature’s filter, historically thriving here in the billions in the early 1900s before Biscayne Bay was dredged and carved up.

“In an 1895 report, they literally described the oysters as luxurious growth,” Aran said.

Today, they are dramatically fewer in number but still present in pockets of the watershed, doing the job nature designed them to do: Eating the pollution from the water they grow in. A single oyster can filter up 50 gallons of water per day, and the females can produce over 100 million babies a year.

“If we get 25 million adult oysters in the water, we’re talking about a $4 billion wastewater treatment plant,” Aran said. “1.25 billion gallons of water a day can be filtered.”

That’s how Aran’s Watershed Action Lab was born, a plan to restore the lost oyster population of Biscayne Bay as a means to save it.

“And there’s an oyster bed — all under there it’s covered in oysters,” he said. “So that’s a perfect example of a living shoreline. It’s providing filtration, it’s creating habitat. We need to understand that biology is key to this nutrient cycling process.

There are two species of oysters here in South Florida, the thinner flat tree oysters that prefer saltier water and the eastern oysters that thrive in more brackish.

You can find them in clusters along dock pilings, mangrove roots and limestone rock in waterways that stretch from Oleta State Park to Miami Beach, down to Deering Estate and in the Coral Gables waterway where Aran is launching his experiment.

“They’re everywhere,” he said. “It’s a question of how can we support the oyster population by giving them enough population so that the predators don’t wipe them out.”

The key is to create more surface area for baby oysters to latch on to. So by stringing together recycled shells cured in the sun for three months to kill any bacteria, these lines are then tied underneath docks near thriving colonies, biomimicking mangrove roots that give the baby oysters an ideal habitat exposed to both air and water as the tide changes.

“So essentially what we’re doing here is we’re trying to create a little nursery under people’s docks for the oysters to grow,” Aran said.

As the oysters develop they’ll be transferred to cages, acting as baby factories, providing a stream of oyster larvae that will flow down the waterway.

Aran is not a marine biologist. He has a master’s in public health and runs a kombucha company with his wife, but Ana Zangroniz is a scientist and is part of the academic team advising him.

“Yes this is going to work,” said Zangroniz, Florida Sea Grant extension agent for Miami-Dade County. “Starting out by hanging these lines under docks seems like a viable way, and we’re pretty confident that if you put shells in the water, they will come.”

And so a community comes together to make this happen. Aran will need a thousand lines to start. So far he has 40.

Said 10-year-old student Shan Ming: “I want to help Biscayne Bay and help to save it.”

Proving no matter the age, everyone can play a role in saving the bay.

“To be able to bring together a community, that’s actively and intentionally gathering for a purpose, to build a healthy and safe Biscayne Bay for our kids and our grandkids, it’s a beautiful thing,” Aran said.

Oysters alone won’t save Biscayne Bay, but they can give the bay more time to breathe as we urgently work to improve our failing infrastructure.

So far, Aran has crowdfunded $15,000 to help finance the mission, and he plans to recruit more schools and volunteers to help finish the lines he needs to launch the project. He’s also looking for volunteers to kayak along South Florida canals to look for living oyster beds that can serve as habitat to install the lines, and waterside homeowners willing to host them.

If you’d like to help, click here to visit his website.

Also see: Freshwater Flow and Ecological Relationships in Biscayne Bay


About the Author:

Louis Aguirre returned home to Miami and Local 10 in September 2017.