The Nature Conservancy. Protecting nature. Preserving life.™

By Judy Althaus

What is it about the common oyster that inspires thousands of volunteers to give up days and weeks of their time? It isn’t just that oysters are delicious.

Along Florida’s coasts, folks understand the important role oysters play in filtering our water and stabilizing eroding coastlines. Oysters also support a healthy ecosystem that offers a prime nursery habitat for fish, crab, shrimp and other critters.

But today, oyster reefs are considered the planet’s most imperiled marine habitat. More than 85 percent have been lost.

The Nature Conservancy employs several novel techniques to restore oyster reefs, including laying “oyster mats” in the knee-deep waters of Indian River Lagoon – one of the most biologically diverse estuaries in North America. Download a fact sheet on the oyster reef restoration project.

Nature.org spoke with the Conservancy’s Anne Birch, who directs the project, to learn why so many are captivated by the lowly oyster.

Nature.org:

Anne Birch:

An oyster mat is a simple concept: We take a sheet of environmentally safe mesh, tie oyster shells to it and weight it to the bottom of the lagoon. Connected together, the mats then create a huge welcome mat to attract free-floating oyster larvae. The larvae settle and produce the backbone of a new, healthy reef within as little as a year’s time.

Oyster reefs face a variety of threats – including overharvesting, disease and pollution – but reefs at this site have been damaged by boat traffic. The new reefs we create with the mats are designed to not be dislodged by boat wakes.

Nature.org:

Anne Birch:

The Conservancy is working with Linda Walters, Ph.D., from the University of Central Florida (UCF) on “intertidal” oyster reefs – those that are exposed during low tides and covered with water during high tides – within Mosquito Lagoon, a section of the Indian River Lagoon.

Dr. Walters found that over time, the constant wave energy from boat wakes will dislodge oysters from their reefs. They tumble into each other and eventually form “dead margins.” These dead margins are exposed above high tide all the time and the tumbled oysters die, leaving barren islands made up of just the oyster shells.

Many other partners have joined the Conservancy and UCF, helping make restoration a success. The Brevard Zoo has stepped up its participation and is now coordinating volunteers to make the oyster mats.

Nature.org:

Anne Birch:

Yes, and they’re fun! Thousands of individuals have come out — from children to fishermen. Several community volunteer events are held each month. And, students in classes from fifth grade through college age tie oyster shells onto the mats in school while discussing the oyster’s role in nature.

By the end of 2010, more than 10,000 volunteers had hand-tied oyster shells onto almost 20,000 mats!

Nature.org:

Anne Birch:

Since 2005 we’ve restored 42 reefs. Restoration will continue through 2012, with funding from the Conservancy and NOAA’s Community-Based Restoration Program, along with partners such as the National Estuary Program the State of Florida and private individuals.

We monitor the reefs every year and results have been excellent! All of our restored reefs are now settled with juvenile oysters. Many have seagrass growing right up to their margins, connecting them with shoreline mangroves to create a natural ecosystem.

Nature.org:

Anne Birch:

Deploying mats in the lagoon can be messy and hot work, but volunteers love to spend time in a stunning setting where dolphins and osprey feed. Volunteers have reef-naming rights, and one reef is called “Sirenia” in honor of a visiting manatee.

Logistics alone — gathering materials, preparing shells, cutting mats, organizing weekly volunteer events, getting folks into boats and out to the sites — can be a big challenge.

A challenge we didn’t foresee was the time it would take to prepare a site for oyster mats by raking down the dead margins. Partners solved this, donating the use of a floating backhoe dubbed “the Marginator”. Right away it raked 12 sites in two days, saving volunteers two years of work! With the Marginator, our progress has almost doubled.

Nature.org:

Anne Birch:

Never underestimate the appeal of the oyster or the power of the community! The grey oyster is actually a very charismatic critter. Whenever we make the mats, we’re surrounded by curious people with oyster stories to tell.

Learning about the ecological benefits of oyster reefs fits perfectly into 5-12 grade studies about estuaries. And making the mats provides school kids with a hands-on lesson and the chance to be involved in a nearby marine project.

Florida’s coastal communities “get it” about how reefs filter water, stabilize shorelines and provide food for so many other critters. More than 140 different species have been identified within our restored reefs – that’s similar to natural reefs.

Nature.org:

Anne Birch:

Certainly! It’s very important to use a science-based approach and the right method for each site. The Conservancy makes sure that monitoring is part of the plan. That’s how we determine success.

The Conservancy will use different restoration methods in northeast Florida, the Loxahatchee River and on Florida’s Gulf Coast, as well as in other areas around the globe. Our scientists share their methods, the pros and cons and successes or failures with one another. It’s an excellent way to “go global” with a local project. See an interactive map of other oyster restoration projects in the American South.

 

Judy Althaus is a conservation writer in Florida.