What’s in ballast water?

THEY called it the blob that ate the Black Sea. Thirty years ago, a ship from North America sailed up the Bosphorus and dumped ballast water containing comb jellyfish from back home. The invader – Mnemiopsis leidyi – went crazy, gobbling up plankton and triggering a catastrophic decline in marine life, including commercial fisheries. At one point its biomass reached a billion tonnes, 10 times the world’s annual fish landings.

A simple drawing of a ballast system.

A simple drawing of a ballast system.

While the quote above from a recent article by New Scientist sounds like a tall tale from a nightmare, it is a true story about invasive species. Invasive or alien species damage the lands and waters that native plants and animals need to survive.

Boats, specifically their thru-hulls and ballast water often accidentally help spread invasive species. One of our Clean Regattas Best Practices asks regatta organizers to require boats traveling by trailer to a different body of water to scrub their hull where they are pulled out of the water. This can greatly help reduce the chances that a recreational boat spreads invasive species.

Zebra Mussels

Zebra Mussels – one of the more commonly known invasive species in North America.

It is very important for recreational boaters to do their part, however it is important to note the impact of the shipping industry in the spread of invasive species as well. The global transport of ballast water is the single biggest cause of marine invasive species being spread in our oceans, lakes and rivers. A United Nations treaty agreed in 2004 that would require ships to install kits to kill off biological stowaways in their ballast water has still not been ratified by enough nations to come into force (including the US). Learn more about this problem and the treaty in the recent article by New Scientist: Ships must kill off the beasties in the ballast water.

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