Reinventing the Oyster

Story and photos by Bill Sherrod, Editor

In an unassuming setting on the banks of the Coan River, a team of

Virginia seafood proponents is working on a comeback plan.

The lowly oyster once anchored � literally and figuratively � Virginia�s mighty seafood industry.    

This crusty, bottom-dwelling bivalve and that more glamorous crustacean, the blue crab, formed the foundation of the Chesapeake Bay �s once-flourishing commercial seafood trade. But this historically prolific fishery has been on the decline for decades.

And while the blue crab�s decline has slowed somewhat in recent years, the oyster � besieged by disease, pollution, over-harvesting and predation from blue crabs and the cownose ray � has all but disappeared from its native territory.

Before the oyster�s decline, vast reefs of oyster beds stretched across thousands of acres of bay and river bottom along the Chesapeake Bay and its tributaries in Virginia and Maryland . Subsequent generations of oysters took root on their ancestors� shells, Nature�s blueprint for the perfect oyster-breeding habitat.

Strategies to restore the oyster to its historic prominence have made some headway. A Northern Neck company � Cowart Seafood � is deeply involved in the effort to reintroduce and propagate oysters in their historic range. Cowart Seafood and Lake Packing Co. Inc. are situated on the Coan River near Lottsburg in Northumberland County. Lake Cowart Jr. manages both companies. His family has been in the seafood and canning business since 1908.

Cowart Seafood and Bevans Oyster Company in nearby Kinsale are working cooperatively on a project to develop a method of growing oysters � or �aquaculture� � that is commercially sustainable. They are working to perfect a system that will provide enough fast-growing, sterile oysters to keep their shucking houses in business. 

In a parallel effort, these two Northern Neck companies are working cooperatively to produce fertile oysters to plant on public grounds, in hopes of accelerating repopulation of the bay�s historic oyster beds. �Oyster aquaculture has been in Virginia for the past two decades,� notes A.J. Erskine, aquaculture manager and field scientist for the project. �It isn�t new � we�re trying to develop a way to produce more oysters, faster.�

A key component in this effort has been development of a �floating upweller� system for nurturing the oysters from the spat stage � oyster infancy, so to speak � to a sort of adolescent phase of the bivalves� development, when they can be put into growing cages and placed in the Coan River to develop to harvestable size.

�We started the aquaculture project in 2005, using a rack-and-bag system,� notes Erskine The rack-and-bag procedure was successful and showed that the temperature, salinity and other characteristics of the Coan River environs would, indeed, be favorable to growing oysters. To produce oysters in the numbers needed to significantly supplement the Cowart Seafood shucking and packing operation, however, a more prolific off-bottom cage system was built. 

The floating-upweller system consists of a line of enclosed, submerged cages attached to a floating platform. A large paddle-wheel is fixed at the open, river end of the platform and keeps water and nutrients circulating through the system of cages, which are filled with the tiny seed oysters.

The sterile seed oysters come from several commercial hatcheries, including one in Mathews, as well as from facilities located in New England and other locales. Sterile oysters are used because they grow faster � there�s no energy wasted on reproduction � and a quality meat yield is realized during summer months. The sterile oyster�s faster rate of growth also lessens the likelihood that it will fall victim to the various diseases that have decimated the bay�s oyster stocks.

The oyster seedlings are miniscule � like grains of sand � when they first arrive at Cowart Seafood. Before they can be placed into the floating-upweller system, they are nurtured in an enclosed downweller system, where they grow large enough to be placed in the more robust environment of the floating upweller.  "The upweller circulates oxygen- and nutrient-rich water through the whole system using the large paddle-wheel,� says Erksine. �It�s like having a high tide and a low tide all at once.� 

It takes four to eight weeks in the floating-upweller system to get a �plantable� oyster, according to Erskine. When the young oysters reach a size between � and one inch in length, they are �graded� and separated out to be put into open-water cages located on private oyster grounds in the Coan.

These cages are 4-by-6-by-1 feet in dimension and hold about 10,000 seed oysters each. The cages have been modified to allow a way out for small blue crabs that have gotten in through the wire mesh. The conical escape route lets the crabs find their way back into the open water, but doesn�t encourage entry into the cage.

As the oysters grow in these cages just off the river bottom, they are checked regularly and separated out by size. Eventually, the cages hold 1,500 to 2,000 oysters when they�re ready to be harvested.

Once the oysters are removed from the upweller and placed into the growing cages in the Coan, it typically takes 12 to 18 months for the bivalves to reach marketable size, about 3 inches in length.  �We planted about one million seed oysters in 2005, and harvested between 2,000 and 2,300 bushels in the fall of 2006,� Erskine continues.

After harvest, the oysters are taken to Cowart Seafood Corporation for shucking, packing and distribution. Cowart Seafood, for example, distributes a wide variety of oyster products to grocery dealers across the nation.

�We�re working on increasing the volume of oysters that can be used in the shucking houses,� notes Jason Kenner, an employee of Cowart Seafood who works with Erskine on the oyster aquaculture project. �We sell oysters frozen on the half shell, frozen breaded, in the shell, fresh shucked in eight-ounce to one-gallon containers, and frozen shucked,�

Kenner notes. "We can process as many as 10 million a year,� Erskine adds. �The need is there, and we�re hoping to refine the process to meet this demand.� 

The floating-upweller system is called an �intensive� form of aquaculture, according to Erskine. A parallel part of the program is �extensive,� and its goal is to produce fertile oysters that can be planted on public oyster grounds and help to re-establish oysters in their historic breeding areas.

The extensive aquaculture system employs wide-mesh plastic bags filled with oyster shells and submerged in tanks, through which raw river water is pumped. Fertile oyster larva are introduced and �strike,� or set on the shells. The shells are then taken out into the Chesapeake or its tributaries and dropped on suitable oyster-breeding bottom on public grounds. As well, sterile oyster larvae are set on shells and planted on private grounds to further diversify aquaculture operations.

The hope is that the fertile oysters will gain a foothold and be the genesis of a growing native population.

This would be good for the Chesapeake Bay and its tributaries for a number of reasons. Economically, it could help begin the process of restoring the oyster to its once-lofty status at the summit of the Virginia seafood industry. This would mean more jobs for watermen, shuckers and packers at the local seafood-processing plants, and more sales of locally produced seafood across Virginia and the U.S.

But even more importantly, an expanding, self-propagating oyster population could help restore the health of the bay itself. "Oysters are a �keystone� species,� notes Erskine. �This means that the rest of the bay�s health is linked to the health of the species.�

Erskine says that a single 3-inch oyster can filter � purify � up to 50 gallons of Chesapeake Bay water a day. And, before Chesapeake Bay oyster beds were depleted, a typical traditional oyster reef consisted of millions of oysters. �Oysters can help clear up algae � this would help to end the algae blooms that have caused the �dead zones� in the bay in recent years,� he adds.

�It could be a great story, and we�re hoping that what we�re doing here on the Northern Neck will in some way help things along,� Erskine concludes.