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Uses of Recycled Oyster Shell in Reef Restoration
Oyster reefs provide a unique suite of benefits as a commercial fishery and vital component of an estuarine ecosystem. They filter coastal waters, protect shorelines, and provide food and shelter for hundreds of species. Unfortunately, oyster reefs are the most threatened marine habitat worldwide with a loss of over 85%.

Heavy exploitation coupled with severe storm events, disease, pollution and habitat loss has resulted in serious declines in US oyster populations. Due to severe pollution, oysters became virtually extinct in New York Harbor in the early 1900s, resulting in the closure of the fishery. The Chesapeake Bay oyster fishery crashed in the 1980s, with an estimated loss of over 98% of its oysters since Colonial times. Galveston Bay once yielded 90% of the oyster production in Texas until hurricanes and over-exploitation diminished 60% of the bay's oyster habitat.

Harvest operations and storm-driven sedimentation reduce the elevation of natural reefs, leaving little to no shell behind. When oysters are harvested, their entire habitat, the 2 valves of their shell, is removed with them. Where one third of the nation's oyster production is sourced, Louisiana, it is estimated that 50-80% of the shell collected during harvest never returns to the water.

While oyster larvae can attach to many surfaces, oyster shells are the preferred substrate for larval recruitment. As it has become increasingly difficult and expensive to purchase oyster shell, sourcing shells from local seafood restaurants or shucking houses has become the common approach to securing cultch for reef restoration. Oyster shell recycling began on the East Coast in the early 2000s and has expanded along the Gulf Coast over the last 10 years. Now, nearly 30 groups in the US are actively recycling oyster shell.

This session will explore how recycled oyster shell is being utilized in reef restoration and shoreline protection. To provide a regional perspective, challenges, success stories and lessons learned will be shared by multiple NGOs representing the East, West, and Gulf Coasts. Methods and design specifications will be discussed to understand the benefits and limitations associated with different strategies such as containing shell in baskets or bags versus placing loose shell. While each organization's efforts differ in terms of scale and strategy, they all share the common goal of returning shell back to its natural habitat to enhance and restore native oyster populations.
Coastal Ecological Restoration – Shellfish