In 1954, Chesapeake harvests rose dramatically in response to a 15 percent increase in ex- vessel price, which was itself the result of a decrease in mid-Atlantic harvests. However, this boom did not last for long. In 1959, the protozoan pathogen Haplosporidium nelsoni (MSX) invad- ed the Chesapeake Bay and, soon after, Perkinsus marinus (Dermo) — both have been responsible for catastrophically killing most of the oysters in high-salinity regions of the Bay. In Virginia, leaseholders, or private growers, hold a majority of their leased bottoms in the high salinity areas affected by MSX and Dermo — public grounds are in the lower-salinity waters. Unlike Maryland watermen, who have depended for their harvests primarily on publicly open grounds, Virginia’s pri- vate industry has been virtually decimated.
In spite of the MSX invasion in the Bay, oyster production in Maryland in the 1960s in- creased for a short period. A major reason for that increase was the discovery of pre-historic fossil shell sources and the development of a dredge to extract the shell for use as a substrate to “catch” natural oyster seed. Subsequent employment of these resources by the State of Maryland was com- monly referred to as the “repletion program.”2
Prior to the repletion program, state legislation had required processors to make 10 percent of their shucked shell available for purchase by the state in order to ensure the availability of sub- strate for future oyster production. The legislation also provided funds for state shell-planting ac- tivities. The discovery of additional shell sources provided a cheap alternative to freshly shucked shell and yielded significant production increases. Maryland’s oyster production doubled from around 1.5 million bushels to some 3 million annually. The increase in importance of the reple- tion program relative to natural oyster set helped transform the oyster fishery from traditional nat- ural resource gathering into a “put-and-take” state fishery.3 Watermen were temporarily relieved of the constraints of nature alone and no longer solely dependent on the “recycling” of processed oyster shell.
The use of relatively inexpensive dredged shell also changed the philosophy of oyster man- agement in Maryland from maintenance of a collapsing industry to revitalization, through reple- tion, of a potentially valuable one. The state switched from its regulatory role of oyster manager to a champion of production growth. Although production began to wane in the late 1960s and has continued to do so, until about 1981 Maryland oyster production remained over 2 million bushels. During this time there was concern that the market could not absorb, at an acceptable price, more than about 2.5 million bushels. In this new scenario, the market, not nature, became the con- straining element.
Since the 1980s oyster production has been suffering from the reappearance of MSX and, es- pecially, Dermo. Maryland’s harvest has declined from over 2.5 million bushels during the 1980-