Improving Habitat Restoration by Replacing Plastic Mesh with Biodegradable Alternatives
Oysters are ecologically and economically important across the U.S. Gulf of Mexico. They create habitat for fish and invertebrates, filter, and clean bay waters, and protect eroding shorelines. Oyster harvest in Texas generates approximately $17 million per year.
Centuries of overharvesting, disease, and changes in water quality have contributed to staggering losses of oyster reef habitat, with less than 15% remaining globally. Because free-swimming oyster larvae depend on shells of older generations for attachment and growth, when oyster reefs are degraded, essential habitat and ecological functions are lost.
Increased awareness of oyster reef loss has led to widespread habitat restoration efforts. One of the most common techniques used for small-scale, community-based reef restoration is to place oyster shells into plastic (polyethylene) mesh bags to create a stable, three-dimensional substrate for larval oyster attachment and growth while minimizing shell loss from currents and wave action. Although plastic mesh is a relatively inexpensive and durable material, there is growing concern about the plastics contamination in the marine environment.
A major limitation to expanding the use of biodegradable mesh beyond the pilot restoration scale is their higher cost relative to inexpensive plastics. We will purchase and use biodegradable mesh in biannual community-based oyster reef restoration events in the Texas Coastal Bend in 2021. At each event, 50-100 volunteers will fill biodegradable mesh bags with recycled oyster shells and place them in St. Charles Bay to form the building blocks for rebuilding degraded oyster reef. The selected area is closed to oyster harvest. We will also support TAMU-CC student involvement in these events.