Alien Marine Crustaceans of Japan: A Preliminary Assessment

摘要: Although invasions may have commenced in the 1500s, our record of alien marine and estuarine species Japan begins largely 1930s. We expand previous inventory 10 to 31 cryptogenic species, underscoring that this, too, be a striking underestimate. Most crustacean into occurred along Pacific coast; number crustaceans form abundant populations urbanized bays near international ports. The specific geographic sources most are not known; studies clarified origins barnacle Balanus glandula (from America), but hybridization or low genetic divergence has inhibited clarification exact source crab Carcinus Megabalanus coccopoma. biogeographic fauna include North Atlantic South oceans. cannot distinguish between ship fouling ballast water as vectors for species; this said, it is probable been major contributor arrival barnacles. No yet known introduced solely by water, an artifact lack collections identification potential ballast-only taxa (planktonic copepods, cladocerans, mysids). Other importations from China Korea shellfish stocking, crabs farming, live bait; all these lead introduction novel stocks associated species. There few examined ecological economic impact crustaceans. Amphibalanus amphitrite appears competitively superior native barnacles negative on their densities. Alien inhabit communities established mussels (which serve prey); “alien communities” occur, example, inner areas Tokyo Bay. European declining some regions while American Pyromaia increasing. cost power industry, shipping, aquaculture fisheries clearing biofouling with other organisms probably severely underestimated. Invasive Species Act was passed 2005, did refer organisms. Consequently, preventing Japan, subsequent dispersal its coastline, proving difficult enforce.