Musseling Back on Invasive Species

The United States Coast Guard plans to release a new regulation for how many stowaway species can be carried in ship ballast water. This announcement has been met with mixed reactions. Invasive species like the zebra and quagga mussels have already breached the Great Lakes, brought here in ballast water. These invasive species have killed off strands of the Great Lakes food web, altering our lakes’ wildlife and even chemical composition.

The technology for ships to comply with the new regulation already exists.  Although imperfect, a combination of the three main treatment methods is very effective at controlling the number of stowaway organisms. A filtration system at the intake and outtake pumps of the ballast tanks keeps larger organisms from being sucked on board or deposited at the ships destination. Ballast water can also be used to cool the ship’s engine, simultaneously killing off organisms that might bypass the filters.

The last most commonly used treatment is biocide chemicals. Although effective, how these biocides react to sea water is not fully studied, and dumping water containing killing agents instead of invasive species is a problem in its own right.

The Coast Guard’s actions are to be lauded as recognition of the importance of addressing invasive species issues to the Great Lakes. The initial ballast regulation was a self-policing program, but as such it was not readily followed. In 2004 it was made mandatory. The proposed changes reflect current International Maritime Organization standards, and will limit a certain number of organisms of varying size to be released. In theory this will make it harder for the displaced species to gain a finhold in the Great Lakes. It is estimated the regulations will be finalized in April 2011, pushed back from the original release date of December 2010.

So, if much of the damage has already been done, what can we hope to achieve by implementing these types of regulations now that our waters are already contaminated?

It’s important to keep in mind that despite the damage already done, Lake Michigan can still be further degraded. Our waters already contain more than 100 different invasive species, but the regulations should not be viewed as too-little-too-late; rather, they should be viewed as a step towards preventing and mitigating future damage.  Secondly, when society gets in the habit of taking regular, systemic action to prevent and mitigate the damage invasives cause the Lake, citizens will become more accustomed and prepared for taking the major actions that will significantly improve lake quality.

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