No-Fishing Zones, Oil Spills and Wind Turbines
“Backwater” Issues Are Important, Too

Homeless Young Oysters: A Shell Of a Problem

Oystershells This is a mountain of oyster shells. I posted this picture to symbolize the mountainous -- but inspiring and important -- challenge that Maryland faces as it prepares to unveil a new program to restore populations of this keystone species to the Chesapeake Bay.

Governor O'Malley is scheduled to make an announcement about oysters at 1 p.m. today at the Annapolis Maritime Museum.  In December, he outlined a vision of building back the Bay's devastated oyster populations by expanding no-harvesting sanctuaries and encouraging underwater farms. He is expected to reveal details of that plan tomorrow.


There is no question that, after decades of overharvesting, pollution, and disease, a rescue plan is badly needed for the Chesapeake’s native oysters.  Harvests have fallen to less than 1 percent of historic highs.

The creation of more oyster sanctuaries would be an excellent way to boost oyster reproduction and protect reef structures that are critically important habitat for water-filtering networks of not only oysters, but also mussels, barnacles, fish, crabs, sea squirts, anemones and other life forms.  Aquaculture has the potential to grow dramatically in the Bay, providing not only more cleaning of the Chesapeake's waters, but also jobs and money for waterfront communities that have been hurt by the oyster's decline.

If this is the direction that Governor O'Malley wants Maryland to go, more power to him. Certainly, the rebound of blue crabs and rockfish in the Bay are examples of how science-based government intervention can work wonders.

But I also published this photo of the Mount Everest of oyster shells for another reason.  I wanted to highlight the reality that saving oysters will be quite a climb, and will require a heap more than just sanctuaries.

No-harvesting zones are absolutely needed.  But oysters can’t grow on just the bottom of the Bay. To survive, young oysters (called "spat") need to attach themselves on top of a hard substance, such as the shells of other oysters.  Hundreds of years ago, the Bay was paved with oyster reefs, so this was not a problem.  But so many oysters have been removed or buried in silt -- reefs in Maryland's portion of the Bay have declined an estimated 80 percent in the last 20 years alone -- that this hard bottom is increasingly rare.

So oyster shells, as a base upon which oysters can grow, have becoming a declining resource.  They are a key ingredient for oyster restoration.  At oyster hatcheries, like the one at the University of Maryland Center for Environmental Science Horn Point Lab (where this photo was taken), researchers badly need old shells as the base upon which oyster larvae can attach themselves before they are planted in the Bay.

"If you are going to rebuild oyster populations, you are going to need some kind of substrate to stabilize the bottom," said Dr. Don Meritt, who runs the University of Maryland hatchery, which provides most of the young oysters for restoration work in Maryland. "Shell has proven to be the best” base for the production of oysters in hatcheries, he said. “You eliminate (these) building blocks, and you are in trouble."

Unfortunately, these building blocks are disappearing. The practice of dredging up old shells to use in oyster hatcheries was halted in Maryland about four years ago after complaints from sports fishermen and charter boat captains that digging them up in the northern Bay was disturbing their fishing grounds.

The 15 foot tall heap of shells behind Dr. Meritt’s lab was sold to the state by oyster shucking houses. But these shucking houses are also dwindling in number, as oyster populations fall.  The Chesapeake Bay Foundation and Oyster Recovery Partnership encourage restaurants and diners to recycle old shells by donating them for restoration work, but this can only provide a limited supply.

Construction materials, such as chunks of concrete from Baltimore's old Memorial Stadium, as well as bits of the old Woodrow Wilson Bridge, have been dumped in the Bay and its rivers as homes for oysters and fish. These materials work, as long as the concrete is broken down into oyster-sized bits and screened.  Oysters are not picky and not vain about their accommodations.  But because transporting large and heavy chunks of concrete is difficult, this method can be highly expensive.  Moreover, Dr. Meritt and others have raised the concern that slabs of roadway and other construction debris are often not clean, which can mean adding pollution to waterways and oysters.

Just last week, this blog featured an innovative new alternative: the construction of concrete spheres called reef balls. These whiffle-ball looking structure can make good condos for oysters and fish in some areas. But, again, it would be expensive and difficult to cover the entire Bay bottom with man-made structures like this.

So we want our Chesapeake’s oysters to return, but where can they find a home?  That's a hill of a question.

Oysterhill




























Article and photos by Tom Pelton

Chesapeake Bay Foundation

Comments

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I know it sounds crazy, but has anyone tried seeding oysters on broken glass? There are a hell of a lot of bottles out there in the recycling world that could be put to use if that were an option...

What about the Grand Isle Oyster Reef Project: Lay a 3-5 inch veneer of smaller-sized rocks (limestone or granite) and oyster shell over existing rock.

Carolyn, I think you are right. Using limestone chunks as a base for oyster restoration has worked. The only question is the cost.

BC, broken glass? Maybe that could work for the oysters (and maybe not....I haven't heard of that one before). But I don't know if us humans would want to dump tons of broken glass into the Bay. I like to go wading and swimming in the Bay, and I hate to think of my feet being cut to ribbons.

Concrete reef balls are a boon for fisheries and allow fishermen and oysters to coexist with no interference. Using these green concrete products will allow the chesapeke oysters to continue to flourish for future generations.

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