Monday, July 22, 2013

The Value of Oyster Shell- Virginia is Dredging River Bottom For It.

Mass Oyster team members are working hard to grow our oyster shell recycling program and we are enjoying seeing them taking off in other areas including Wellfleet and Martha's Vineyard.  It is interesting to see how other state's are going to great lengths to obtain shell; literally spending millions of dollars to access supply and support their coastal ecosystems. Here is a piece on Virginia.
Jim Wesson on shell dredging
7:42 p.m. EDT, July 12, 2013

A superstructure some 70 feet high is anchored in the James River across from King's Mill, harvesting barge after barge of fossilized oyster shells.The shells have been buried in sediment for 10,000 years, ever since the planet began to warm after the last Ice Age.

Now a billion of them are being dredged up over the next month, brought to the surface, washed and planted in deteriorating reefs to try to rebuild some of the best oyster rock sites in Virginia. It's the only such operation in the world, officials say.
"It's remarkable that we have the technology to be able to harvest these fossil shells from the bottom of the James and transport them to recreate a new layer of shell for new oysters to grow," said Doug Domenech, observing the operation Monday.

 Domenech is theVirginia's secretary of natural resources and an advocate of state efforts to replenish and rebuild the state's diminished oyster population and fishing industry. He was invited to watch the shell dredging by the Virginia Marine Resources Commission, or VMRC, from the deck of the agency's 43-foot custom deadrise, a low-slung vessel favored by oystermen.
'Gold rush for shell'

Virginia has been planting oyster shell since the 1920s, said VMRC's oyster expert, Jim Wesson. Oysters were once so plentiful in Hampton Roads that they supported a thriving fishery, their reefs so massive they were a hazard to river vessels.

Filter-feeding oysters also helped clean the waters of the Chesapeake Bay and its tributaries – a single oyster is capable of purging 50 gallons of water a day.But overfishing and invasion by two parasitic diseases deadly to oysters decimated the population and the fishing industry.The state's efforts to restore the stock and the fishery include restricting harvests and planting empty shell on state-owned public oyster grounds to give baby oysters, or spat, a hard substrate to attach to so they can survive and grow.

Oystermen harvest spat-on-shell from public grounds and relocate them to privately leased grounds, where they're tended until they grow to market size, typically within three years.
Shell-planting has made oyster shells a hot commodity — "There's a gold rush for shell," said Wesson.

For years, the state has purchased empty shell from shucking houses, but most such operations are small and too far away — chiefly in the Northern Neck — for cost-effective transport to the James.
Years ago, oystermen prospecting for old buried shell in the James found a cache of about 22 acres on the James City County side of the shipping lane, said Wesson.

Since 2000, the state has hired a private company to dredge that site as funding allowed, but funds have been spotty, with annual appropriations by the General Assembly ranging from zero to $1.3 million. This year, legislators appropriated a record $2 million, launching what state officials say is the largest replenishment effort in Virginia history.

'Our nest egg'
The massive hydraulic dredge superstructure sits in water 6- to 12-feet deep and bores into the river bottom with a corkscrew-like device. Wesson likens it to mining for pea gravel. Water shoots the shells up into the superstructure and onto conveyor belts, where they're washed, sorted by sieve into large and small sizes, and loaded onto one of two barges on either side of the structure. Sediment is returned to the river bottom.The smaller shell will be used to build the reef base, with the larger pieces placed on top and around the border. Oysters spawn in summer, so the new shell will soon be fresh habitat for new spat.

No comments:

Post a Comment