First report of the invasive eel pest Pseudodactylogyrus bini in North America and in wild American eels

We detected 2 species of monogenean gill worms, Pseudodactylogyrus bini (Ki kuchi, 1929) Gusev, 1965 and P. anguillae (Yin & Sproston, 1948) Gusev, 196 5 (Monopisthocotylea: Pseudodactylogyridae), on American eel Anguilla rostr ata in 2 rivers in South Carolina, USA. One of these, P. anguillae, was rep orted 5 yr ago from Nova Scotia; as well as in South Carolina, we also disc overed it in 2 localities in Chesapeake Bay. Differences in the morphologie s of specimens of either species of worm from North America and northeaster n Asia were negligible. Similarly, the level of variation in sequences in t he ITS2 (internal transcribed spacers) region of ribosomal RNA was minor, a nd not consistent with geographical origin. These data indicate that these monogeneans invaded North America only recently, possibly in parallel with the nematode Anguillicola crassus (which is known to have been introduced w ith commercial imports of foreign eels). We map the current global occurren ce of these monogeneans, and conclude that their dispersal from northeaster n Asia was largely as a result of the eel trade, and has probably been seco ndarily augmented by longshore migration of infected eels, and possibly als o by transport in ballast waters. With present technology, all eel stocks m ust still be collected from the wild; unless shipments are disinfected at q uarantine, these and other eel pathogens (such as A. crassus) are likely to continue to colonise other regions of the world.