Sometime in 1979 or perhaps 1980 a bulk cargo ship pushed off from a port in the Americas, with a load of wheat or iron ore, bound for a Russian port on the Black Sea. Perhaps it was winter, and the vessel needed more weight to keep it down in stormy seas. Or perhaps the vessel was “‘high on the nose,” and needed extra weight to keep its bow down just a little more. The ship “ballasted up,” pumping water into its bottom ballast tanks, and adding another 1,000 metric tons to a forepeak tank. The voyage went well: cargo and water were released on the north shore of the Black Sea, 22 days later.

Carlton, J.T. 1996. Marine bioinvasions: The alteration of marine ecosystems by nonindigenous species. Oceanography 9(1):36–43, https://doi.org/10.5670/oceanog.1996.25.

This is an open access article made available under the terms of the Creative Commons Attribution 4.0 International License (https://creativecommons.org/licenses/by/4.0/), which permits use, sharing, adaptation, distribution, and reproduction in any medium or format as long as users cite the materials appropriately, provide a link to the Creative Commons license, and indicate the changes that were made to the original content. Images, animations, videos, or other third-party material used in articles are included in the Creative Commons license unless indicated otherwise in a credit line to the material. If the material is not included in the article’s Creative Commons license, users will need to obtain permission directly from the license holder to reproduce the material.