While in port, shipping vessels often suck huge quantities of water into their ballast tanks to replace the stabilizing weight of cargo they’ve off-loaded. Along with this water comes abundant aquatic life, such as mussels and crabs, which journey with the ships—often crossing entire oceans—until the ballast is dumped in preparation for loading new goods.
Log in
Subscribers, enter your e-mail address for full access to the Science News archives and digital editions.