Marine crustacean invasions in North America: a synthesis of historical records and documented impacts

We examine the history and relative importance of marine crustacean invasions for North America. Nearly 400 non-native species of invertebrates and algae have established populations in marine and estuarine waters of North America. Of these documented invasions, 28% are crustaceans, contributing the largest number of species of any taxonomic group. Crustaceans also dominate non-native species richness on each coast of North America, but there are strong differences in the total number of non-native species and in their taxonomic distribution among coasts. Crustaceans contribute prominently to the current knowledge base about marine invasions, due both to the large number (proportion) of documented introductions and also the extent of research on the group; they are thus a potentially important model for understanding marine biological invasions in general. Using an analysis of available literature, we evaluate what is known about the impacts of 108 non-native crustaceans in North America. Ecological and economic impacts are reported for many (28%) of these species, but they are rarely well documented, resulting in low certainty about the magnitude, spatial scale, and temporal scale of effects.