On Monday, I got to participate in (mostly by watching and documenting) a joint project with the POA and the Nature Conservancy under the supervision of Joy Brown.  The Nature Conservancy is part of an ongoing effort to restore oyster habitat all across the American South. They estimate that

decades of over-harvesting, disease, pollution and declining habitat have decimated the massive oyster reefs that once dominated the country’s coastal estuaries.  Globally, 85 percent of reefs have been lost, making oyster reefs the most severely impacted marine habitat on Earth.

As a result, they are experimenting across the South with a variety of techniques to improve oyster habitat.  (The Summer Issue of Nature Conservancy Magazine featured these ongoing projects)  Our project is trying a few new techniques, so this is real science.  Reef restoration hasn’t been tried in a managed (impounded) wetland, so this will shed some light on whether it is even possible for oysters to grow there.  In addition, this type of shell substrate is not usually in the impoundment, and we don’t even know if the oysters will adhere there.  Theoretically, the oysters will help clean the impoundment, provide oxygenation, and create habitat for a variety of other marine life, including fish and crabs.  Since a fully functional reef takes 3-5 years to grow, it may be a while before we know how successful we are.

To see a photo gallery of shipping the shells over, click here.

We took fossilized oyster shells and created a “reef” of sorts

in the impoundment near the crabbing dock.  This was a big effort on the part of the staff, because they had to use the heavy equipment to move the shell material first to the area near the dock, then use the lull to lower it so that volunteers could rake it out of the bed of the lull and into the impoundment.  Island community member volunteers included Paul Connelly and Julia Mullins.   Standing knee deep (or waist deep) in the impoundment, and keeping an eye on an alligator sunning on the bank (who eventually moved on), our island volunteers were joined by Paul’s friend Mickey and Nature Conservancy volunteers Ryan Olson, Neil Jordan, and Tom Dooley.

Joy directed everyone to spread out the shells in the marked area, and rake them into peaks and valleys from 2-3 feet below the surface of the water.  The task was made harder by the murkiness of the water, and by the fact that the shell was heavy, so we went slowly so as not to sink the earlier deposits under the weight of the later ones.

This is an interesting project which should contribute to the health of the impoundment.  The South Carolina Department of Natural Resources calls oyster reefs “an integral part of the marine ecosystem.” Oyster reefs enhance habitats for other oysters, fish, and crabs, Conservation projects often recycle oyster shells in order to provide surfaces for oysters to grow on. (Here’s a link to SCDNR’s Life History of an Oyster.) Oysters themselves filter water at astonishing rates (one source said 20, one said 50 gallons per day.) In the Chesapeake (where it is estimated that less than 1% of the original oysters remain,) some scientists estimate that in the 19th century, oysters would have filtered the entire bay in just one week.

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SCDNR has some other oyster restoration projects.  Here’s a link to their site.  The scientists at DNR estimate that in some of our areas busiest creeks (those in neighborhoods and areas of dense development) virtually no oysters remain.  That’s why there is such a massive shell recycling program in the state.  If you’d like to volunteer, there are chances to help bag shells at Fort Johnson.

Oysters begin life in a cloud of released eggs and sperm in the water column.  Fertilized eggs mature into zooplankton and provide food for lots of animals in the water.  Eventually, they become “spat”, about the size of a pepper flake, and secrete shell-like chemicals.  At this point, they land on a substrate (usually oyster shells, but occasionally other stuff like wood) and begin their life as a sedentary creature. Large groups of oysters form reefs, which in turn provide habitat for a wide variety of other marine organisms.

http://www.nature.org/magazine/summer2010/features/

http://www.dnr.state.md.us/fisheries/recreational/articles/oysterrestoration.html

http://www.nature.org/initiatives/marine/features/oyster.html

http://score.dnr.sc.gov/
http://chesapeakebay.noaa.gov/oysters/oyster-restoration

SCDNR’s Life Cycle of an oyster

One more source was Life Along the Inner Coast, by the Lippsons