Delaware environment: Saving oysters while there’s something to save
Project aims to boost funding, population
http://www.delawareonline.com/article/20101008/NEWS02/10080357
By MOLLY MURRAY • The News Journal • October 8, 2010
Between 2005 and 2009, the baby oysters that settled onto shell reefs in the Delaware Bay reached record numbers.
Scientists believe the reproductive success was linked to a four-year, $5 million project to add clam shells to existing oyster reefs in the Delaware Bay.
The clean shell – about 2.1 million bushels placed on 1.3 percent of the total shell beds in the bay – provided new habitat for baby oysters, called spat. In 2006, for instance, the rate of recruitment, as it is called, was 10 times higher on the beds with new shell than those without it.
But federal money for the shell-planting project dried up last year, and now the Partnership for the Delaware Estuary is scrambling to raise private dollars to resume the project.
One of the biggest fears is that bay oyster reefs – in better condition than most throughout the region – could deteriorate to a point where restoration would no longer be an option, said Eric Powell, director of the Haskins Shellfish Research Lab in New Jersey. The question, he said, is “do we want oyster reefs in the bay or do we not?”
Oyster reefs support a fishery, provide habitat for other fish resources and the bivalves – which are filter feeders – and help improve water quality.
Once you lose the reefs, it gets expensive to rebuild them, Powell said.
So the partnership, a Wilmington-based nonprofit established as part of the Delaware National Estuary Program, is proposing a public-private partnership to continue smaller-scale shell planting.
The plan, said Jennifer Adkins, executive director, is to raise $200,000 by April and plant additional shell just before the oyster spawn.
The partnership has committed $50,000 to the project and hopes to raise the other $150,000 from private sources, she said.
Adkins said no donation is too small: A few weeks ago, a woman donated the proceeds from a yard sale, she said.
“This money is needed to revitalize oyster reefs before the summer spawning season,” Adkins said. “Otherwise, countless baby oysters, or larvae, may never mature to filter the bay’s water, provide habitat for marine life and reach marketable size.”
Oysters reproduce by broadcasting sperm and egg into the water column. The larvae move in the water and then cement themselves to hard surfaces – like existing oyster reefs.
The fresh shell provides additional habitat.
In the Delaware Bay, the oysters are so desirable that they are sold for the half-shell market. That means commercial fishermen are harvesting the oysters shell and all.
But they compensate for what they are removing by contributing to a fund that goes to Delaware and New Jersey to buy and restore shell.
The trouble, Powell said, is not shell loss from harvest but loss from oyster disease.
“The total number of deaths, that’s really the problem,” he said.
Oysters are considered a keystone species in the Delaware Bay because their huge biomass contributes to spawning and nursery areas for other fisheries and because of their contribution to water quality.
In the 1880s, the commercial harvest reached a peak of 2.4 million bushels a year and Delaware Bay oysters – both canned and on the half-shell – were a delicacy.
There were an estimated 500 oyster boats working the oyster beds in the bay, and fortunes were made in bayfront communities like Port Mahon in Delaware and Bivalve in New Jersey.
The harvest was half that in the 1950s but still robust.
Then the oyster disease MSX hit. In a matter of months, an estimated 50 percent of oysters on the beds were dead. By 1960, 49,000 bushels of oysters were harvested.
Through the 1970s and 1980s, the fishery made a slow recovery, and in 1988, a second oyster disease, Dermo, hit.
Powell said Dermo is directly related to climate change in the estuary and rising water temperatures.
“It would not naturally be in Delaware Bay,” he said. “It’s here because Delaware Bay has warmed up.”
Even with the disease, the beds hung on.
The trouble is, they eventually put oyster reefs into a negative shell balance “and that’s something that can’t be easily fixed.”
The oysters that survive still are reproducing and the shell that is there continues to provide habitat, but because of lower reproduction, there is less new shell created on the reef.
From 2004 to 2005, the Army Corps of Engineers in Philadelphia and New Jersey and Delaware partnered for the shell-planting project.
“It was so successful,” said Barbara Conlin, a marine ecologist with the corps in Philadelphia.
Then “our funding ran out,” she said.
Part of the frustration for state and federal partners is that money is still available for oyster habitat restoration in the Chesapeake Bay.
The National Oceanic and Atmospheric Administration has spent more than $27 million on oyster reef restoration in the Chesapeake since 2004.
Conlin said that the Delaware Bay shell project supplemented shell on about 1,000 acres of existing oyster reefs in the bay.
They estimated that in one year, they had a $40 return for every $1 invested based on the shellfish harvest alone.
“We spent $5 million and had remarkable success,” she said.
This year, prices for Delaware Bay oysters are high – $50 per bushel, Powell said. That compared with $40 to $45 a bushel in a normal year, he said.
The one uncertainty with the oyster project is how much shell it will take before Delaware Bay oyster reefs can be self-sustaining again.
Conlin said she believes there is a point where harvest levels – with the contribution to the shell fund – will make a reef project self-sustaining.
But Powell said doing nothing is taking a huge risk. Once reefs are badly damaged or gone, “the cost is absolutely astronomical” to rebuild them. Here in Delaware Bay, the total reef acreage hasn’t declined, he said.
“If we invest a little money each year,” he said, “the cumulative cost is lower than one big reef project in the Chesapeake.”