It is only 9:30 AM, but the air at Kingman Farm is rapidly approaching dreaded soup territory. We pass by several long rows of compost, steam rolling gently off the recycled remains of unfinished meals from University of New Hampshire dining halls. This old farmland in Madbury seems an unlikely place to come across seashells.

But as Ray Konisky of the Nature Conservancy pulls his truck around the compost to the far end of the field, that is exactly what we see. Most of the shells have already been shoveled into one-ton bags, primarily through the month-long physical efforts of just 2 people, Konisky and UNH’s John McLean, the Kingman Farm Manager. The pile that remains will soon top off the few unfilled bags, which themselves will soon be loaded onto trucks for their trip back to the ocean floor.

John McLean of Kingman Farm

The shells are part of an effort to restore oyster reefs in Great Bay. No one knows how much of this most northern of significant oyster reefs on the Eastern seaboard was destroyed with the advent of dredging for oyster harvesting in the 19th century. But we do know the extent of the destruction in the last 40 years. In the 1970s, Great Bay was home to 1000 acres of oyster reef. That coverage has dwindled to just 50 acres.

According to Konisky,  a “three-threat” is the culprit in the 95% die-off. The first of these is disease. Two parasites traveled from the south to hit Great Bay in the 1990s and hit oyster populations hard. The second is water quality; as development on NH’s seacoast has increased, so too have silty deposits and excessive nutrients. Silt covers existing beds and the rock or shell bottoms that oyster larvae, or spat, need to latch onto. Spat requires a hard surface to mature, which silt fails to provide. Nutrients can lead to algal blooms, depriving the water of oxygen. Finally, harvesting still has an impact, though much smaller. 300 harvesters are allowed to take half a bushel of oysters a day.

The good news, if there could be any out of this, is that the oysters that are left in the bay are resistant to the parasites. By 2006, these oysters were “loaded with spat,” according to Konisky. What was lacking were hard-bottom places for spat to make a home. And that’s where these tons of shells come in.

In 2009, a pilot project was launched by Dr. Ray Grizzle’s Oyster Restoration Program at UNH and The Nature Conservancy to place recovered shells in Great Bay near the mouth of the Oyster River. The hope was that the shells would provide a spot for spat to latch on, and the beginnings of a new reef would form. In July, one fifth of an acre of shells was laid down. Upon return to the site in the fall, researchers found 30 live spat per square meter, indicating 25,000 total. With this level of success, the ante was upped for 2010, and a full acre of shells is expected to be laid down in the bay.

Ray Konisky with the bagged shells.

Of course, shells aren’t particularly easy to come by, nor are they easy to transport. A consortium of three restaurants on the seacoast, with help from the Coastal Conservation Association, donates approximately 10 tons of shells to the effort. While this seems like a lot, each ton is only enough for one 20-foot diameter circle. The vast majority of the shells is donated by Blount Seafood in Warren, RI. The shells are trucked to Kingman Farm, where this year’s batch has quarantined for six months. In July, the bagged shells will be placed on a 50 foot barge, and dropped on the Great Bay floor at the rate of 25 bags a day.

The reef is augmented by “spat on shell,” which are hatchery-raised larvae, placed both on the new reef, as well as on the docks of 30 volunteer homeowners. The larvae come from UNH’s hatchery at Jackson Lab.

The effort required to lay down shells is significant. Financing and logistics are the two major hurdles that must be overcome each year. For example, loading the shells requires heavy equipment, and the work is very labor intensive. State government agencies, including the  Department of Environmental Services and NH Fish and Game, have been supportive, so permitting has not been an issue.

2010’s target area continues to be the Oyster River, and in 2011, the target will be the Lamprey. Eventually, Konisky sees the mouths of all seven bay tributaries receiving shells.

“If you look at the old maps, oysters were at the mouths of these rivers,” says Konisky. “They were the natural filtration system for the bay.”

As Konisky prepares to deal with the final pile, he explains that the Great Bay is not alone in needing oyster restoration efforts. Indeed, oyster reefs are one of the world’s most threatened ecosystems, with 85% of the world’s known oyster reefs now destroyed.

“We’ve got the goods here,” he says, pausing for a moment. “If we can help nature along in what it does, rather than replace it.”