Planting more oysters can help Lowcountry fight rising waters | News SC Climate and Environment
WADMALAW – Ask one of the Barrier Island Oyster Co. crew members about their product and they’ll quickly give you insight into the oyster and all its superpowers.
The Lowcountry staple provides habitat for all sorts of creatures in an estuarine environment; it acts as a filter for water, helping to improve its quality and clarity; and it stabilizes our marshy shores.
Small-scale ‘mariculture’ farmers raise single oysters from ‘seed’ (oyster larvae after they attach to a surface) to market size via floating cages at Ocella Creek off Wadmalaw Island – a core business model co-founder Josh Eboch sees as intrinsic to a greater mission.
Restoring our shorelines and improving the waterways we take from are key to ensuring oysters stay in South Carolina for years to come, he said.
Farmers like Eboch have found important allies among scientists, conservationists and government officials in a joint effort to better understand and engineer the superpowers of the oyster, especially its ability to protect marshes and the sea and to reduce the risk of flooding.
“Nobody cares more about drinking water than an oyster farmer because we’re literally selling it,” Eboch said. “We sell it encapsulated inside this oyster.”
Oyster reef systems form natural breakwaters, as they allow marshes to grow and extend the shoreline. The spongy swamp is meant to absorb flood waters, just as it does during a high tide, Eboch said.
Simply put: if there are more oysters, there is more marsh, which means there is more material to break the force of the waves and ultimately absorb the water. In coastal South Carolina, this could help offset the risk caused by climate change.
Flood Risk Mitigation
Much of the Lowcountry sits a few feet above sea level, making it particularly vulnerable to rising waters. And as the seas stretch upwards – 2.7 inches in the 2010s alone – powerful rainstorms and tides are constantly wreaking havoc on the region.
Nowhere are the effects more evident than in Charleston Harbor, which circles the city’s peninsula. Rising sea levels have pushed harbor waters about a foot higher over the past century, causing major flooding to increase.
Oysters adapt particularly well to rising sea levels because they increase the reef with the water level, said Dale Morris, resilience manager for the city of Charleston.
A rigid shell allows oysters to stay in place against waves or wind power, helping to slow the effects of waves. This leads to less water pushing into the swamp, and even less water pushing past the swamp into roads and houses.
The science behind this particular superpower is not a new phenomenon, but there is concern that humans have realized too little, too late how oysters can be used proactively to offset the risk of flooding.
Overdevelopment on living shorelines, or the spongy swamp formed in part by oyster reefs, has destroyed much of what Mother Nature has given us, Morris said.
Today, scientists, conservationists, marine farmers and government officials are scrambling to better understand how to “build with nature” and create these shorelines themselves.
After harvesting their single-shell oysters each week, Barrier Island oyster farmers Maddie Piascik and Hamlin Auld set aside any leftovers that can’t be sold, placing them in large buckets to throw in the water to replant them.
The larvae are attracted to the shell, which gives the oysters the ability to nurture each other, Piascik said.
Piascik and Auld repeat the process over and over, in hopes that one day farmers will be able to harvest wild oysters from the restored bed.
As a shellfish licensee, the company must pay rent to SC’s Department of Natural Resources for its water section, as well as do its part to replace the resources it takes.
Every calendar year, all licensees must meet a planting quota of 50 bushels of oysters per acre, said Ben Dyar, head of the department’s shellfish management section.
MNR allows licensees to employ a variety of restoration techniques to meet the quota, leaving it up to them to choose the best strategy for their area.
In addition to saving the white shell – the dead, dried stuff – and giving it to the DNR to replant, Barrier Island farmers first chose a tried-and-true method: placing bamboo sticks less than 3 feet deep inside the soft muddy ground. oyster beds.
Barnacles will start growing on the sticks, making the rock candy-like structures very heavy. If well placed, the stakes intersect as they fall, supporting each other along an embankment.
Oysters are attracted to the calcium carbonate present in the barnacles, extracting the chemical compound to build their shell as they attach themselves to the bamboo.
This method of reef restoration is simple, but can be expensive. And placement is key — put the pegs in the wrong place, and they’ll eventually disappear, Auld said.
The farmer went “really crazy” the first year he tried the method, putting up around 3,000 stakes in one area, he said. Auld returned months later to find mud swallowing the bamboo, rendering them virtually useless.
The company discovered another restoration technique through conversations with DNR officials, Eboch said. The green shell, or the shell that still has live muscles attached, can also be placed back into a reef to help other oysters grow.
Although originally a new concept for Eboch, replanting green shells has become one of the company’s main goals, he said.
More to learn
Oysters are resilient, yet temperamental creatures. Working with your section of water to understand its idiosyncrasies – flow, temperature, depth – requires trial and error, which can quickly consume time and resources.
Auld, Eboch and Piascik agree that they want to increase their restoration efforts well beyond the quota required by the DNR, but the small company is limited in what it can realistically achieve.
And Barrier Island still has a lot to learn when it comes to restoration techniques. A centralized repository for this knowledge – where to put the bamboo poles so they don’t get washed away; how to find more optimal sites in the lease — would be helpful, Eboch said.
MNR sends official letters twice a year to permit holders, advising them when they can plant and how much of their quota remains.
State officials also talk with farmers throughout the year, helping them develop strategies to best manage their leases, Dyar said.
“If we receive feedback from licensees that they need more advice and more information, we are more than willing to look into that,” he added, acknowledging the possibility of a bad communication.
This concerted effort to recycle, replant and redesign the oyster shell has the potential to be very profitable.
Scientists and consultants are scouring Charleston for places to build living shorelines, said Morris, who works for the city.
The Army Corps of Engineers continues to work on a project to place an 8-mile levee around downtown Charleston to prevent flooding. This plan is encountering objections from some stakeholders.
Recent versions of the plan propose building live oyster reefs on the shoreline parallel to the surge wall.
There are likely other places where living shorelines could be built, but challenges include having the money to do so and finding the most suitable environments to support oyster reefs, Morris said.
Nevertheless, farmers like Piascik and Auld will still be on the water every day tending to their lease.
Piascik, dressed in rubber waders and work gloves, will pick up one of the buckets full of seashells while Auld guides his motorboat along a section of the salt marsh. She’ll tip the bucket, allowing the quiet stretch of Ocella Creek to fill with the rhythmic rattling of the oyster shell returning to its rightful home.