For centuries, American oysters played a significant role in New Hampshire’s Great Bay Estuary. The hard-working bivalves that feed by pumping and filtering anywhere from 20 to 40 gallons of water a day kept the bay and tidal rivers clean.
But by the 1990s, most people considered New Hampshire oysters a lost cause. Overharvesting, pollution and disease had taken a severe toll on oyster beds that once covered huge tracts of the sea floor in Great and Little Bay and stretched into the Oyster, Lamprey and Bellamy rivers. Marine scientists estimated there were about 50 acres left of what was once one of the richest oyster grounds in New England.
But thanks to the back-breaking work of the New Hampshire chapter of the Nature Conservancy and the staff at the University of New Hampshire’s Jackson Estuarine Laboratory, oysters are making a slow and steady comeback.
Rebuilding oyster beds
Ray Konisky, the Nature Conservancy’s director of marine science, was at the Gundalow Company in Portsmouth last week updating a small crowd of citizen conservationists on the latest phase of the oyster restoration project. The plan is to rebuild about 100,000 square feet of oyster beds in the bay.
"All of our oysters are for eco-restoration," said Konisky, who believes oysters can lend some serious help to communities trying to reverse the effects of decades of damage.
Last June, Konisky and fellow conservationists from UNH hired a barge to tow 225 tons of recycled surf clam shell to the mouth of the Lamprey River. Crews dropped the shell into the water to create a foundation for a new oyster reef.
While the surf clam shells were settling into the water, volunteers and UNH students were tending tanks of oyster larvae, or spat, already growing on recycled oyster shells.
In September, those shells and babies went into the water at the reef site; they are expected to yield about 500,000 oysters.
Unlike clams, which seem to enjoy muck and sewerage, oysters need a cleaner environment. Part of the problem for oysters in the Great Bay Estuary has been the silt that flowed in with the rivers and covered the sea floor. Mopping up decades of mud wasn’t an option, so The Nature Conservancy decided the next-best thing would be to cover it with an oyster-friendly foundation — recycled surf clam shell.
"Rebuilding oyster reefs is a simple and sustainable way to restore the water quality in the estuary," said Konisky. "We don’t manage these things, we build them and they go on their own."
The food chain
The Nature Conservancy started building recycled shell reefs in 2009 with a small pilot program. Encouraged by results, they expanded the rebuilding to an acre of sea floor in 2010. The shells placed in the water last spring cover 2 1/2 acres of sea floor.
Some projects that have used oysters to bump up water quality have kept them in cages while they filtered out pollutants from different waterways. But Konisky is going for something more than a quick cleanup.
"Oyster reefs are a habitat that support other species of small fish and marine life," he said. The constant filtering of excess nutrients from the bay should also contribute to the overall health of the eelgrass meadows, which are habitats for crabs and lobsters. So rebuilding oyster stocks may ultimately strengthen the food chain and the entire ecosystem. It’s a lot to ask of one mollusk, but Konisky has faith in oysters. He said he’s willing to try to do whatever it takes to accommodate them as they resettle into Great Bay.
"We’re making this up as we go along, and the more people we have involved the better," he said.
It hasn’t been too hard to get people who live by the bays and rivers on the oyster bandwagon. Some people who turned out for the talk at the Gundalow Company remember their fathers coming home with a fresh-picked bag of oysters ready to roast or put into a stew. They welcome the chance to someday be able to experience that themselves.
And while the oysters beds being rebuilt by the Nature Conservancy will be off-limits to harvesters, the hope is the beds will become spawner sanctuaries that contribute to repopulating the rest of the estuary.
Volunteers step up
Volunteer energy fuels the oyster restoration project and people are contributing in a variety of ways. New loads of recycled oyster shells are needed for each generation of oyster larvae raised at the UNH hatchery. Volunteers from the Costal Conservation Association make regular rounds to local seafood restaurant and fish markets, where they collect about five tons of oyster shells each year.
And several dozen people who live on the waterfront on the bays and rivers are raising oysters in cages kept at their docks.
"That gives us information about the best places to grow oysters," said Konisky. It hasn’t been a huge surprise to learn that the biggest oysters seem to come from the Oyster River. And while those big, home-grown oysters might be tempting, everyone knows that for now, the focus is science, not stew.
"Nobody eats anything," said Konisky. "It’s all about helping the bay."
Special to the Union Leader
November 21, 2011
Reprinted with permission.