Invasive Species

Aquatic Invasive Species

Asian shore crab, Hemigrapsus sanguineus

With the arrival of zebra mussels in the Great Lakes more than a decade ago, local, national, and international attention have focused on the establishment of non-native, invasive or nuisance species in freshwater and marine habitats. Aquatic plants like water chestnut, hydrilla, and Eurasian water milfoil choke local lakes, adversely affecting recreational activities, and depressing lakefront property values. The Asian shore crab, Hemigrapsus sanguineus (image, left)has become the dominant intertidal crustacean in the Northeast, displacing both native and non-native crab species; its omnivorous diet includes juvenile mussels, other crabs, and seaweed. Marine tunicates foul boat lines, dock pilings, and are causing problems for some shellfish industries. The pathways for species from their native habitats to new ones are many, including ballast water, recreational boats and bait buckets, live seafood shipments, discharges of unwanted aquarium organisms, and other intentional as well as inadvertent means. It is a global problem costing enormous ecological and economic problems.