Reference: Bin/. Bull. 180: 72-80. (February, 1991) The First Historical Extinction of a Marine Invertebrate in an Ocean Basin: The Demise of the Eelgrass Limpet Lottia alveus JAMES T. CARLTON 1 , GEERAT J. VERMEIJ 2 , DAVID R. LINDBERG 3 , DEBBY A. CARLTON 1 , AND ELIZABETH C. DUDLEY 4 ^Maritime Studies Program, Williams College Mystic Seaport, Mystic, Connecticut 06355; ^Department of Geology, University of California, Davis, California 95616; 3 'Museum of Paleontology, University of California, Berkeley, California 94720; and 4 Department of Zoology, University of Maryland, College Park. Maryland 20742 Abstract. Lottia alveus, a gastropod limpet once found only on the blades of the eelgrass Zostera marina from Labrador to New York in the western Atlantic Ocean, is the first marine invertebrate known to have become ex-tinct in an ocean basin in historical time. The last known specimens were collected in 1929, immediately prior to the catastrophic decline of Zostera in the early 1930s in the North Atlantic Ocean. The brackish water refugium ofZoslera throughout the decline was apparently outside of this gastropod's physiological range, and the limpet became extinct. Few marine invertebrates have habits as specialized and ranges and tolerances as narrow as did L. alveus. The fact that most marine invertebrates have large effective population sizes may account for their relative invulnerability to extinction. Introduction There are no reports of the post-Pleistocene extinction of any marine invertebrate, in spite of the fact that hundreds of terrestrial and freshwater species of animals and plants have become extinct as human activity has increased around the world (Martin and Klein, 1984: Vermeij, 1986; McNeely et a/.. 1990). This is perhaps even more remarkable given the widespread perception that many marine invertebrate species have suffered ex-tensive decimation and that a number of them are on endangered species lists (for example, Gee and Wilson, 1981; Franz, 1982; Wells et ai, 1983; Wicksten, 1984). Received 18 July 1990; accepted 24 November 1990. We report here the first historical extinction of a marine invertebrate from an ocean basin. The limpet Lottia alveus (Fig. 1), a once abundant stenotopic species that ranged from southern Labrador to Long Island Sound and lived only on the blades of the eelgrass Zostera marina (Conrad, 1831;Couthouy, 1839; Gould and Binney, 1870), is now extinct in the Atlantic Ocean. Here we consider the evi-dence for this conclusion and suggest why this extinction occurred. Materials and Methods Field studies Eelgrass populations were searched specifically for lim-pets in the following locations: Cape Cod, Massachusetts, between 1979 and 1982; along the eastern Connecticut shore (Fishers Island and Long Island Sounds) between 1982-1987 and 1989-1990, and at Vinalhaven (25 km east of Rockland). central Maine in 1984 (J.T.C. and D.A.C.); at Boothbay Harbor (45 km southwest of Rock-land), central Maine in 1971, and in Newfoundland (Come by Chance, in Placentia Bay, and at Norris Point, Bonne Bay, in the Gulf of St. Lawrence) in 1990 (G.J.V.). We contacted biologists who are familiar with the common Atlantic limpet Tectura testudinalis (= Acmaea testudi-nalis) and who have sampled Zostera epiphytes in Quebec (Rimouski), Nova Scotia (Halifax), Maine, Massachusetts, Rhode Island, and Connecticut. Since 1965, L. alveus has been searched for without success in south-central Nova Scotia, and in Labrador and Newfoundland (D. Davis and R. Noseworthy, pers. comm., respectively). We examined 72
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