If you want to study invasive species in the ocean, the Panama Canal offers a lot to explore. The ships passing through can inadvertently transport plants, animals, and even parasites from the Atlantic into the Pacific, or the reverse direction. Some species stow away in ballast tanks, others cling to ship hulls. In this video Mark Torchin, a scientist at the Smithsonian Tropical Research Institute, shares some of the invasive species-related questions he's investigating near this oceanic thoroughfare. For a look at non-native species in colder climates, read a blog post about their prospects in Alaska's coastal waters.