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Oyster shells in a pile are open and empty.
Recycled Shells Discarded oyster shells can be used for other purposes. © Kaming Cheung/TNC

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Oyster Recycling

TNC launches a pilot oyster recycling program in Mississippi.

The Nature Conservancy in Mississippi will launch a pilot oyster shell recycling program aimed at understanding the potential impact of using oyster shells collected from local restaurants to help support and improve the vital oyster populations and industry along the Gulf Coast of Mississippi.

Recycling and deploying used oyster shells becomes an effective type of natural material – commonly referred to as “cultch” – that can be placed in the water for oyster larvae to grow on and produce new oysters. Currently, most of the used oyster shells are being discarded without reuse and are ultimately a lost resource that could utilized for restoration. 

Shells collected by restaurant staff will be set aside and later collected for the oyster shell recycling program. Mississippi’s Gulf Coast is “substrate limited” with generally plenty of oyster larva, but a need for places for oysters to attach. The collected oyster shells will become a valuable attachment surface for baby oysters to grow. 

“It’s very straightforward - take the actual oyster shell and reuse it to help restore the very resource it’s providing. But the devil is always in the details. We want to learn from the other successful programs like this in other states, work through the kinks and make this a viable program for Mississippi," said Alex Littlejohn, state director, TNC in Mississippi.

“Oyster shells are one of the best places for new oysters to grow. That is how they do it naturally, and with this program eating and enjoying oysters can be an act of conservation,” said Tom Mohrman, TNC’s director of marine programs. “Implementing this pilot project is an opportunity to support the local fishing community, local restaurants, and to also give back to the environment while protecting and growing a valuable natural resource.”

Oyster populations and subsequent harvests have decreased over time throughout the Gulf of Mexico as well as in the Mississippi Sound. Causes of oyster declines often vary between bays, and may be a result of overharvesting, natural and anthropogenic disasters, water quality, as well as a reduction in oyster reef habitat. Oyster reef habitat is comprised of cultch--a hard substrate often made up of oyster hash, shell, and other hard bottom features on which oyster larvae can attach. It is widely held that oyster shell is the best cultch material to use to maximize oyster larvae adherence and recruitment. Oyster shell recycling programs have been implemented throughout the coastal United States to reuse discarded oyster shells from restaurants, festivals, and other venues. 

The pilot program will have two phases. The first part of the project is to perform an analysis of the oyster shell recycling program’s economic and operational sustainability to determine how an oyster recycling program can be sustainably implemented in Mississippi. This analysis will consider various factors including supply, long term collection, storage, and deployment of oyster shell used to maintain the State’s oyster resources. This analysis will result in a written economic sustainability plan that will guide the second phase of this program. 

The activities in the second phase are dependent on the outcomes of the first phase and anticipated to include working with restaurants to collect oyster shells, calculating how many shells are collected over time, and beginning the process of curing that material and preparation for restoration.

This project is paid for with federal funding from the RESTORE Council and the Mississippi Department of Environmental Quality under the Resources and Ecosystems Sustainability, Tourist Opportunities, and Revived Economies of the Gulf Coast States Act of 2012 (RESTORE Act).  NOTE: The data, statements, findings, conclusions, and recommendations are those of the author and do not necessarily reflect any determinations, views, or policies of the RESTORE Council or the Mississippi Department of Environmental Quality.

The Nature Conservancy is a global conservation organization dedicated to conserving the lands and waters on which all life depends. Guided by science, we create innovative, on-the-ground solutions to our world's toughest challenges so that nature and people can thrive together. We are tackling climate change, conserving lands, waters and oceans at an unprecedented scale, providing food and water sustainably and helping make cities more sustainable. Working in 76 countries and territories: 37 by direct conservation impact and 39 through partners, we use a collaborative approach that engages local communities, governments, the private sector, and other partners. To learn more, visit www.nature.org or follow @nature_press on Twitter.