Fifteen years ago, the Great Bay estuaries were an oyster metropolis.
Twenty five million animals stacked atop shells of their dead ancestors formed acres and acres of oyster reef.
Now, the Great Bay is more like an oyster ghost town, with just a fraction of its former population.
Scientists at the University of New Hampshire are working to reverse the oyster’s decline by reseeding the estuaries.
New Hampshire Public Radio’s Kerry Grens has more.
Washed oyster shells from Maryland ready to be placed in the reef, sit in a tub in front of Peter Jones who is mending a trawl net. (Cheryl Senter, NHPR)
...sounds motor and waves...
Professor Ray Grizzle leans over the side of a motorboat and peers into the water.
Grizzle: Turn back to the starboard toward the island.
He directs his technician to steer the boat over a reef of oysters they planted in the Great Bay three years ago.
...tonging sounds...
Using ten foot long oyster tongs—which resemble two large, rusty rakes clamped together—Grizzle brings up a handful of Crassostrea virginica, the eastern oyster.
Grizzle: These are really beautiful. They’ll be reproducing this year.
Oysters reach reproductive maturity at right around three years of age, when they are about the size of the palm of your hand.
It’s also the age when MSX—a deadly parasite in the Great Bay—strikes its host.
Grizzle says many oysters are infected when they’re young.
Grizzle: It doesn’t appear to do much until that 2nd or 3rd year, and then all of a sudden they just quickly die in a matter of days.
Grizzle blames MSX for much of the ninety five percent decline in New Hampshire oysters over the past fifteen years.
The loss, he says, affects the entire estuary ecosystem.
Oysters provide habitat for other organisms, food for fish and crabs, and each one filters twenty to thirty gallons of water a day.
Grizzle: And they filter down to the level of microbes. It can go in quite turbid looking, murky looking, and the water that comes out from the exhalant siphonal area is clear.
Standing on the bow of the boat, Professor Ray Grizzle looks out over the Great Bay estuaries. (Cheryl Senter, NHPR)
This cleaning service is especially important to the Great Bay system, which suffers pollution from sewage overflows and failing septic systems.
While Grizzle’s mission is to rejuvenate these so-called ecosystem services, the trick is to outsmart the MSX parasite in the process.
Grizzle: Our basic approach is to try to introduce oysters into the population here that have a natural disease resistance. They’re all Crassostrea virginica, the eastern oyster, but they’re from different brood stock lines that have been raised in a diseased challenged environment and have survived to reproduce.
Grizzle’s been doing this for five years now, testing different strains of disease resistant oyster and experimenting with different reef sites.
He says he’s added about a half million surviving oysters since his project began.
Another quarter million weren’t so lucky.
Grizzle: We’ve lost fifty percent on one reef, probably to MSX because there’s no harvest there. And we’ve lost nearly one hundred percent on another reef, Salmon Falls, which was a smaller reef, had 75,000 oysters on it. But they did very well for four years. Very well.
Some of the reefs exist in harvestable areas.
Grizzle’s technician, Holly Abeels, says they inform oystermen about their project and ask them to stay off the reefs.
Using oyster tongs, Grizzle brings up oysters from one of the beds.(Cheryl Senter, NHPR)
Abeels: And they’re pretty cooperative because they want more oysters to grow too for them. And if our oysters spawn and the larvae go over there, then there will be more oysters for them in the coming years. They really help to work with us.
Grizzle’s ultimate goal is to have breeding reserves for the animals: reefs that are free from harvesting so they can spawn and replenish harvested reefs.
Bruce Smith with the Department of Fish and Game says closed areas like this already exist—but not by choice.
Smith: It’s a defacto reserve system. It’s brought on by the fact that we have pollution.
Large swaths of the Great and Little Bays and the rivers that feed into them are closed long term to harvesting because of wastewater and bacterial contamination.
And like the animals themselves, oyster licenses have declined about ninety percent.
Smith: We just can’t sell these things or promote these things for sale knowing that the resource is in decline.
With Grizzle’s help that downward trend could turn around.
The goal established by Fish and Game is to restore 20 acres of oyster reef by the year 2010 and Grizzle has established three.
He expects two more acres to be added this fall when he sends a million baby oysters to find their new home on a reef in the Bellamy River.
SOQ
