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New Hampshire

Oyster Restoration Reaches New Depths

Juvenile Oysters

In just 3-4 months, juvenile oysters can triple in size. These oysters are ready to go to their new home on the reef.

Juvenile Oyster Clusters

The Nature Conservancy's Kristin Ward and Ray Konisky plant juvenile oysters in the Oyster River.

NH Chronicle

The Oyster Restoration Project was recently featured on NH Chronicle!


"Our tightly-coupled systems are breaking down.   But recovery of oysters gives us real hope.”
~Ray Konisky

Pop Quiz: How many gallons of water can one adult oyster filter per day?

A. 2 gallons
B. 5 gallons
C. 15 gallons
D. 20 gallons

Chosen your answer? Great!

At the height of feeding in summer an adult oyster can filter a whopping 20 gallons of water per day!  1,000 oysters can together filter the entire volume of your average swimming pool - about 20,000 gallons - every day.  Back in 1970, research suggests that 900 acres of oyster reefs in Great Bay were able to filter the volume of the entire estuary every 4 days.  After 40 years of decline from disease, overharvest, and siltation, that rate is now about 274 days – a not even enough to make a blip.  The decline is staggering to say the least. 

Recognizing that healthy oyster populations are essential in improving the water quality of Great Bay, Dr. Ray Konisky has been hard at work in the water.  Ray, along with University of New Hampshire’s Dr. Ray Grizzle and Krystin Ward at the Jackson Estuarine Laboratory, completed another season of oyster restoration work in October by planting 200,000 juvenile oysters on a newly created 1-acre clamshell reef in the Oyster River.  In December, a sampling for live oysters indicated excellent initial survival rates, along with an added settlement of 7,000 – 15,000 naturally spawned oysters on the clamshell.  Combined with restoration efforts in 2009, our work over the past two years has added 1.2 acres of live reef and nearly a quarter of a million new oysters to the Great Bay Estuary.  We may be far from filtering the entire bay every 4 days, but it’s a start.

“Oysters are unique,” says Ray.  “We have too many nutrients and too much algae in the [Great Bay] system.  Oysters clear the water and help eelgrass meadows which in turn provide places for more fish, lobsters, and crabs.   Our tightly-coupled systems are breaking down.   But recovery of oysters gives us real hope.”
2010 also saw the fifth year of the Oyster Conservationist Volunteer Program.  32 volunteers at 21 locations around Great Bay participated in this year’s program, successfully raising more than 3,000 healthy juvenile oysters. These oysters joined those hatched at the Jackson Estuarine Laboratory on the newly constructed reef in October. A very heartfelt thank you goes out to all our “oyster nannies”!

Hatchery-raised oyster spat are happiest developing on oyster shell.  To provide some of that shell, our partners at the Coastal Conservation Association (CCA) coordinate the collection of used shell from local restaurants and fish markets (see our fall 2010 newsletter for an in-depth look at the CCA Shell Recycling Program).  New participants are added all the time.  To see which businesses in your area participate, visit the CCA’s website at

Over 225 tons of clam shell recently left their winter home at the UNH Kingman Farm and moved to the docks in preparation for 2011 reef construction.  The goal is to restore two acres of historic reef at the mouth of the Lamprey River this summer.  With UNH hatchery seeding and some help from Mother Nature, this site should be the new home for ½ million oysters by year’s end!  As these reefs and the existing reefs in the Oyster River mature, we might just start turning the tide on the nutrient threat.  Our efforts are underway thanks to generous grants to The Nature Conservancy and UNH Jackson Estuarine Laboratory from the Piscataqua Region Estuaries Partnership, NOAA, NH Moose Plate Program and Conservancy member donations.  Funds are largely in place for 2011 but looking ahead, we are going to need lots more help.  To learn how you can support our efforts, contact Marne Perreault at 603.224.5853, extension 12, or  

There's lots more on the Oyster Restoration Program!

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