Oyster gardens: how we build the natural reefs protecting our coasts

Signs of hope can be few and far between in these times of climate and environmental crisis — but witnessing the installation of a new reef made from the reuse of shucked oyster shells is one of them. It is a sign that dealing with climate change is within our grasp; it is a choice.

Climate change impacts coastal communities in more unique and expedient ways than non-coastal communities. Given that billions of people around the world live on or near the coast, paying attention to coastal issues beyond a warming climate is imperative.

Restore Our Shores, based in Melbourne, Florida, protects these delicate coastal ecosystems that have borne the brunt of human and environmental damage. It does so by conducting environmental restoration projects, including along and within the estuaries of Florida’s Space Coast. And they do it using oysters.

At Restore Our Shores, there is a saying: “If you haven’t been cut yet, you haven’t been handling enough shell.” That’s because this unique way of rebuilding reef ecosystems relies on razor-sharp, reused oyster shells. And these reefs can be big or small. Many in Florida have something now compared with a garden; a short stretch of area populated by oyster reefs between their property or land and the open water: an oyster garden.

The reefs we build work against the effects of a warming climate and the stronger storms associated with it. More importantly though, according to conservation specialists, the species that will one day take hold on these reefs will also remove pollution like microplastics and pharmaceutical products from the water, preventing them entering the water cycle that we rely on.

The reefs represent a new gardening programme Restore Our Shores developed to address common coastal challenges. In Brevard County, Florida, permanent and sustaining additions to waterfront property are available free to property owners along the lagoon front. This is due to a half-cent sales tax that passed Brevard in 2016, a County that benefits from an influx of spectators at every major rocket launch.

These Florida reefs are among the first Restore Our Shores has constructed in the face of a complex amalgamation of government permitting and regulatory bodies.

But regulation is just one of the factors associated with building these all-natural and restorative reefs, which hold such promise in the global fight against climate change and coastal degradation.

Restore Our Shores rents a barge to transport crates of oyster shells from their processing and sorting center across the lagoon to each site. The shell though, comes free. Under the Shuck and Share programme, Restore Our Shores collects leftover oyster shells from area restaurants that serve the mollusk on their menu. The organization cleans and sorts these shells into crates called gabions so that they may one day make a reef that sustainably provides ecosystem-level benefits.

Each crate must be in near perfect line to the next, a conservationist or volunteer stands at each end on the outside of the worksite — pre-demarcated with underwater survey stakes — with PVC poles to guide unique line of sight for the team lowering the shell gabions into place. Restore Our Shores has laser guidance equipment, but often simple methods are more useful.

The placement of each crate isn’t only important to appease construction permitting, they must be close and at proper angle so that the reef can perform one of its most important purposes: breaking wave energy; slowing or reversing erosion caused by storms of increasing strength. There is no local firm producing oyster garden gabions, so Restore Our Shores gets their materials from a local fence supply store and folds each crate into form on a T-shaped piece of hinged plywood.

Once all the gabions are lowered into place, they must be secured to each other. A crate loose to its neighbor is liable to be pushed out of place, disrupting the structure of the reef while it is still in a vulnerable stage and before full adult oysters, in many ways the bedrock of these reef ecosystems, have taken root atop the old shell. To do this, team members dive underwater and tie gabions together across multiple points of contact.

After the perimeter has been lined with gabions 18-kilogram bags of loose shell which are cut open and spilled such that the shell falls inside the corral. At this point it is necessary to watch for soup cracker wrappers and silverware –— he last remnants of the dinner table. The shell is then shifted until the reef is flat, all shell is contained and everything is in optimal condition to be seeded by larvae or spat from nearby reefs or by Restore Our Shores themselves.

Every reef constructed is directly seeded by Restore Our Shores, as they can’t necessarily rely on environmental feedback loops to establish new populations on the dead shell, and regulatory restrictions on piecemeal operations mean new reefs are not always constructed in proximity to naturally aid this process.

Once a reef has been established, oysters get to work. A single adult oyster can clean nearly 190 liters of lagoon each day. The oyster garden requires little support, an underwater bubbler must be installed and maintained by the homeowner, who benefits from increased property values and the protection having a coastal reef provides, and one day may even be able to harvest the reef for sustenance.

The potential of these reefs cannot be overstated — whether they are in small, garden forms, or in larger constructions. Oysters clean water, filtering out pollution and undesirable elements. They strengthen coastal areas against erosion. What’s perhaps more is that they are constructed from natural by-products of human activity: oyster shells.

Restore Our Shores’ vision is to repopulate coastal areas In Florida with these natural reefs. Moving in this direction by easing regulatory restrictions, improving access to data and sharing and measuring efficacy while building up the oyster-shell recycling system stands to benefit billions of people worldwide living next to coasts — as well as the rest of us whose health is underpinned by the ocean.