The video above from National Marine Sanctuaries explains how three alien species are causing big trouble for marine environments. All three have traits that give them an unfair advantage over native species, thereby allowing them take over and ruin existing habitats. These particular invaders were carried or dumped into their new homes, but they still offer a glimpse into what scientists fear on a global scale as organisms react to an undersea world altered by climate change.
The waters off of the southeastern U.S. Atlantic coastline, in the Caribbean, and in parts of the Gulf of Mexico are now infested with lion fish. These exotic-looking creatures are native to the Indo-Pacific region, so experts suspect that they were transplanted over time by pet owners dumping them into the Atlantic. Lion fish have no natural predators, and their voracious appetites are proving disastrous to reef biodiversity and health.
In the same areas, orange cup corrals—which likely arrived by clinging to ships, or in water that ships used for ballast—are displacing countless native corals from their reefs.
Up north, zebra and quagga mussels are displacing native species in the Great Lakes, tipping the local food chain out of balance, and degrading shipwrecks that had been serving as productive habitats. The mussels came to the lakes in ship ballast, beginning in the 1980s.
When an alien species takes over a habitat, the effect can be catastrophic. With the drastic effects of climate change only getting worse, it’s no wonder scientists are anxiously watching the seas.