Alien Marine Biota of Europe

Abstract

The recognition that marine species in European coastal waters originate from other parts of the world has lagged, in somecases centuries, behind their postulated arrival. The NW Atlantic soft shell clam Mya arenaria is considered one of the earliest introductions: it was proposed that it had been brought in the 16th century intentionallyas bait or food, unintentionally with in solid ships' ballast, with oysters (Hessland 1946). But it may have been broughtearlier still: a find of Mya shells from the Kattegat, Denmark that was dated to 1245–1295 excited a debate on possible transport in Vikings' vessels(Petersen et al. 1992). Vikings aside, the history of marine biological invasions most likely began with the development of“global” maritime trade routes in the 16th century. Some of the first observations of vessel-transported alien species dateback to the 17th and 18th century: live specimens of Balanus tintinnabulum were described and illustrated from a vessel coming from West Africa and wrecked off the Dutch coast in 1764 (Holthuis andHeerebout 1972). The first record of the east Pacific Megabalanus coccopoma in European waters dates to 1851, from a vesselin Le Havre, France (Kerckhof and Cattrijsse 2001). Indeed, Darwin (1854) himself suggested that barnacles had been transportedas foulants on ship hulls, and he was the first to record the Indo West-Pacific Balanus amphitrite from the Mediterranean and the Portuguese coast. But it was the excitement attending the excavation of the Suez Canal thatfocused attention on possible mass incursion of alien marine biota from one sea to another. On the eve of the opening of theCanal Vaillant (1865: 97) argued that the cutting through the Isthmus of Suez offered an opportunity to examine the immigrationof species and the mix of faunas from both seas. Indeed, within 20 years two Red Sea molluscs, the Gulf pearl oyster Pinctada radiata and Cerithium scabridum, were collected in Alexandria and Port Said (Monterosato 1878; Keller 1883).