Every time this huge tankers let out water out, they are infecting an area with the organisms from the last place they picked up water.
In the Great Lakes, the Zebra Mollusk is a terrible threat, and now thes mollusks are carried on boats to other lakes. These Zebra Mollusks are now being found in small lakes in the middle of the Great Plains.
There are similar examples for all the countries of the world.
It's a mess.

I still blame the dolphins for this mess.