The hard clam (Mercenaria mercenaria) is one of the most important commercial species harvested in Virginia's Bay waters. Annually since 1987, dockside values have varied from $4 million to $6 million, with more than a millions pounds of meat landed each year.
In addition to their economic value, the hard clam plays an important role as both filter feeder and recycler in the Chesapeake Bay with the decline in oyster resources. Filter-feeding organisms help to clarify the water through their biological processes, removing particulate matter and potentially toxic materials, providing for a healthy marine environment.
With the decline of oysters, there has also been an increase in the exploitation of hard clams. Areas, such as the James and York rivers, are receiving a lot of pressure from commercial clammers. And as a result of heavy harvesting of public clam grounds, the need for mature, spawning clams is a concern.
The hard clam fishery in Virginia is concentrated on the seaside of the Eastern Shore and in the rivers of the lower Chesapeake Bay. The mouths of the James and York rivers provide large areas with salinities greater than 15 parts per thousand and less than 35 parts per thousand, which are essential for the growth and survival of clam larvae.
Spawning occurs in hard clams when environmental cues trigger males to release sperm as females are releasing eggs. An increase in the probability of successful fertilization, and thus settlement of new clams, can be achieved by high densities of spawning clams in a given area. Keeping this in mind, the Virginia Marine Resources Commission has devised a way to increase the level of productivity in these areas by designating hard clam broodstock sanctuaries. Coordinating with biological scientists and computer modelers from the Virginia Institute of Marine Science and individuals within the hard clam fishery, VMRC staff select protected sites to place large numbers of clams to increase reproductive potential.
The Hard Clam Broodstock Program was created and in April 1995, the pilot site at Lower Brown Shoals in the James River was designated.
The Back River Reef Broodstock Sanctuary, the second site in the program, was created in February 1997. This site was selected because of its potential for larval disbursement within the Bay, the protected status of the area from commercial fishing ressure and the presence of material on the bottom to provide protection from natural predators. An initial deployment of 15,300 clams was invested in early April 1997; a second allotment of 15,300 clams followed in mid-April. Additional deployments are planned to create a sustained broodstock site and to enhance and perpetuate wild stocks.
The Middle Ground Light Broodstock Sanctuary, the third site in the program, was created in March 1998. It was selected because of its potential for larval disbursement within the immediate Hampton Roads area. The site will receive an initial deployment of 30,000 bushels of dredged oyster shell to prepare 2.4-2.9 acres of bottom for the placement of 300,000 seed clams, along with 7,455 market-size clams (2-2.875").
Subsequent deployments of clams and mitigation material will be made as funding becomes available. The VMRC has more clam broodstock sanctuaries planned and will be initiating the development of each site in the near future.
The broodstock sanctuaries are expected to produce very positive results for the clam fishery, yet there is a hindrance working against us. Currently, chowder clams (adult spawners) are being harvested not only for table fare, which are of minimal value in comparison to littlenecks and cherrystones, but for bait in commercial crab pots. Chowder clams, which normally go for around 8 cents a clam are now selling for up to 20 cents apiece.
This poses a problem in the spring, when adequate supplies of preferred crab pot baits (menhaden and bunker) are not readily available. The dilemma stands: Commercial clammers are getting generous dockside prices for chowder clam sales to commercial crabbers, yet they are hurting themselves in the long run by harvesting the broodstock chowders that will provide themselves, along with generations to come, with clams for the future.
It is understood that the commercial clammers are trying to make a living as are the rest of us. But, if the mature chowder clams are returned to the bottom, there will be a continued abundance of more profitable littlenecks and cherrystone clams for the watermen in the future.
The hard clam is one of the top commercial seafood species harvested in Virginia's Chesapeake Bay waters and one of the key elements in filtering those waters. The VMRC is trying to promote the success of hard clams in the Bay and its tributaries by implementing the Hard Clam Broodstock Program.Planting the adult clams in such tight, environmentally friendly sanctuaries will help to promote mass spawn-outs in the future and a large dispersal of larvae. The extensive distribution of the clam larvae by tidal currents will help to increase the stability of the clam resource.
This will, in turn, improve the productivity for commercial watermen and increase water quality for everyone.
Ryan W. Cool
Fisheries Management Technician