MNN - Mother Nature Network

 

Massive oyster reefs once lined the floor of Georgia’s estuaries. But decades of over-consumption, pollution and declining habitat has decimated the oyster reefs in Georgia and in every other coastal state of the contiguous United States.

 

Globally, 85 percent of reefs have been lost, making oyster reefs the most severely impacted marine habitat on Earth.

 

Because oyster reefs are essential to a healthy marine system, The Nature Conservancy is working with federal, state and academic partners to test a variety of techniques to restore oyster reef habitat in coastal Georgia.

 

On Sapelo Island, Georgia, the Conservancy and a host of government and academic partners are testing two methods of reef restoration along an eroding intertidal bank on Post Office Creek.

 

The goal is to produce a Living Shoreline – a natural alternative to hardened materials that have traditionally been used to armor eroding habitat.

 

At one site, Gabion baskets made of chain-linked welded steel measuring 6 feet by 12 feet are filled with a combination of bags of shell, loose shell and rock. The cages are then embedded along 230 feet of the creek bank.

 

At another site, mesh bags of used oyster shells are arranged in 2 layers along a 370-foot section of the creek bank and secured with non-treated pine stakes.

 

Volunteers not only helped bag nearly 8,000 bushels of oyster shells, but they also helped plant 2,000 native trees and plants behind both restoration sites. The vegetation will establish a root system to stabilize the soil and provide habitat for marine life.

Altamaha Sound

From July to October 2009, the Georgia Department of Natural Resources (DNR) and the Conservancy began installing Fish Attractant Devices (FAD) in the Altamaha River estuary.

 

About 150 FADs were placed along the vegetative edge of a marsh island. Each FAD is constructed with a 24 x 24-inch concrete base measuring 3.5 inches thick and embedded with 2.5-feet cement-coated PVC pipes extending vertically from the base.

 

The FADs are designed to provide good vertical relief, so that free-floating oyster larvae attaches to the PVC pipes and the concrete base, ultimately growing into reefs. While this method is limited to areas with firm substrate, Georgia DNR has had great success using this technique to develop inshore fishing reefs.

Bellville Boat Ramp

In 2008, researchers with the Georgia Department of Natural Resources, with support from the Conservancy, began to construct the foundation for oyster reefs to grow near a popular boat ramp in north McIntosh County along the Sapelo River. Three different types of materials were used:

 

• Oyster Shell
100 mesh bags of oyster shells were placed on a firm substrate along a stretch of an eroding vegetative edge of the river adjacent to the boat ramp. The University of Georgia Marine Extension Service donated mesh bags and oyster shell.

• Oak Bundles
Live oak tree limbs, downed by a hurricane, were wrapped with agricultural fencing to create 125 oak bundles, each 3 feet in diameter.

• Spat Sticks
600 spat sticks were constructed by covering bamboo, measuring 6 feet in length, with resin and then dusted with cement. The spat sticks were named after oyster spat, the tiny oysters that larvae transform into when they attach and bond to form reefs.

 

Researchers placed 2 rows of oak bundles along in the intertidal zone – the area submerged during high tide and exposed during low tide – and staked them down with spat sticks. The space between the rows was filled with the remaining spat sticks.