Mollusca of Assateague Island, Maryland and Virginia : a reexamination after seventy-five years

A comparison was undertaken of molluscan collections in waters surrounding Assateague Island by J. Henderson and P. Bartsch in 1913 and collections by the present authors during 1988-1989. In 1914, Henderson and Bartsch reported 38 species of bivalves and 44 species of gastropods as compared with 33 species of bivalves and 40 species of gastropods in the present study. Of 82 species reported by Henderson and Bartsch, 50 are now present in Assateague waters plus an additional 25 species, including one species of Polyplacophora, and the cephalopod Loligo pealeii , that were not reported in their study. Of 11 gastropod taxa erected by Henderson and Bartsch for specimens collected in Chincoteague Bay, two species have been synonymized and the remaining nine species were not found in the present study. Stabilization of an inlet with a stone jetty after the hurricane of 1933 produced a salinity change in the bays of Assateague Island that may be responsible for some changes observed in the molluscan fauna.