CAUSES UNDERLYING THE HISTORICAL DECLINE IN EASTERN OYSTER (CRASSOSTREA VIRGINICA GMELIN, 1791) LANDINGS

Abstract

Landings of eastern oysters (Crassostrea virginica) along the United States East Coast (mainly Rhode Island through South Carolina) increased to nearly 27 million bushels by 1890s, but they then declined by nearly 60% to 11.5 million bushels by 1940 and by almost 99% to 0.35 million bushels by 2004. Though overharvesting usually has been cited as the primary factor for the decline in landings from 1890 to 1940, the principal causes were: (1) a fall in demand for oysters, because consumers became aware that oysters could contain pathogens and competition from other foods increased in markets; (2) three economic depressions; and (3) biological and physical damage to the oysters and their beds (predation, siltation, severe storms, channel dredging, and harvesting by dredges). As a consequence of a huge decline in oyster landings in Delaware and Chesapeake Bays during and after the 1960s because of high oyster mortalities caused by the diseases MSX and Dermo, space became available in the United States national oyster market. The oyster industries of Prince Edward Island, Long Island Sound (Connecticut and New York), and the United States Gulf Coast took advantage of this and increased their production.