What more could you ask for? A lot, it turns out!

At a recent presentation at the Schiller Center, Bowdoin College’s Coastal Studies Center on Orr’s Island, and in conjunction with the Harpswell Heritage Land Trust, the public was invited to learn about a study being conducted by the Basin Oyster Project. Professors Cait Cleaver of Colby and Michèle LaVigne of Bowdoin presented their work on restoring oyster reefs:  From the Bottom Up, A Community Based Approach to Oyster Reef Restoration.*

Besides being tasty briny morsels, oysters serve many functions that are important to our environment. These filter feeders, when occurring in reefs, also help reduce wave energy, provide shelter for young aquatic life, and have potential as part of “living shorelines” to strengthen shoreline resilience. Due to overexploitation and degraded habitat, oysters and oyster reefs are not as naturally present as in the past. Restoring oysters in the environment and the potential for them to reproduce, survive and create reefs are the core of the work being done through this project.

Because naturally occurring oyster reefs are helpful to the environment, The Nature Conservancy began a study in 2017 to explore the possibility of reef restoration, and the effects such reefs could have on water quality and habitat.

The study required an aquaculture license in order to grow oysters, in this case, a Limited Purpose Aquaculture (LPA) license which is regulated by the State of Maine. LPAs are small, (400 square feet), and must be reapplied for annually. In 2020, the town of Phippsburg was asked to take over the study and a second LPA was acquired for comparison purposes.  The research described in this presentation began in 2020 and continues today. If results indicate the ability to help oyster growth and environmental progress (clean water, biodiversity) through methods explored in the study, and without negative impacts, the researchers hope for replication elsewhere.

Like all good research, this study set out to answer important questions.  Among them are:

Is it possible to build an oyster reef? Could oysters, when introduced into an area, sustain themselves; could they reproduce and settle, adding to the introduced oysters?  The study demonstrated that they can. As with all research, there were false starts—the newly introduced oysters needed to be large enough to resist being destroyed by invasive green crabs, for example.

Another question: Could the newly-settled oysters survive?  To this point some have, though not a lot. This gives room for optimism.

And another: Does this introduction of oysters change habitat; that is, are there more species and greater biodiversity? And does changing habitat have negative implications as well as positive? They have seen an increase in fish, periwinkles, crabs (both native and green). Study of habitat impacts continues.

One more: What chemistry is most suitable for oyster growth? Looking at carbon chemistry, nutrients, water temperatures, salinity, oxygen levels are all part of the research. Siting of oysters toward reef restoration requires understanding what environment is most likely to offer success.

The researchers stressed that this study is being conducted with community involvement. This can’t be underestimated in its importance to a successful project. The LPAs are located in Phippsburg waters and the local community is engaged in a variety of ways. Realizing that larger oysters were needed to avoid the problem of green crab predation, the researchers started buying “uglies,” unmarketable oysters, from local aquaculturists—a real plus for the local economy. In addition, the researchers have sought and continue to seek community input and community building through the conservation efforts involved in the study.

Caution for public health is also critical to this research. In Maine, shells are considered solid waste and end up in landfills. If cured for a year in sunlight, and with a DEP permit, shells can be returned to the environment. The researchers are looking at other states regarding best practices for shell recycling that also protect public health.

After the lecture the Quahog Bay Conservancy provided (and shucked!) oysters for the crowd in a full-circle moment. Thank you to all the partner organizations and presenters who put on this exciting, informational event!

To see the slides from the presentation, click here.

*With Support from Basin Oyster Project Partners, Phippsburg Conservation and Shellfish Commissions, Maine Oyster Company, New England Salt Water of Maine, Manomet, Midcoast Conservancy, Bowdoin College, Colby College, University of Maine, Nature Conservancy.