Sunday, April 19, 2009
The Great Lakes ecosystem is vulnerable to invasive species. The photo to the left is of a mass of zebra mussel shells. This species was introduced into Lake St. Clair in the mid-80s and quickly spread throughout the lakes. Native to the Caspian Sea region, this mussel was brought here like most invasive species to the lakes, in ballast water.
It occupies a niche in the ecosystem that was not occupied, so the mussel population exploded.
The second photo is of an alewife. This is a fish native to the Atlantic. If you've ever been on the beach in the spring after a quick warm-up in the temperature of the lake, you may have seen massive die-offs of the alewife population. They cannot handle the stress of a quick change in temperature.
A new regulation was recently put into effect that requires all vessels coming into the Great Lakes system (from other fresh water systems) to rinse out their ballast tanks with salt water. This will purge most fresh water species before they can be transported into the Great Lakes, but it is not a perfect solution. This point is illustrated by the alewife, an Atlantic Ocean species.
So, what is the solution?
There are ways to treat ballast water to insure that no live creatures or plants survive to thrive in the Great Lakes. The water can be treated chemically or with UV light. What needs to happen for this to happen? Lisa Jackson, the new head of the EPA, vowed to review regulations for the Great Lakes. She could enact a new ballast water regulation. While there is no pending legislation in Congress, it is a good idea to alert your representatives to your concern over invasive species in the Great Lakes.
Why should you care? Zebra mussels, alone, have required up to 5 billion dollars to contend with since they arrived. Water intake pipes used to bring in lake water (for cities like Chicago) or for industry (like the three nuclear power plants on Lake Michigan) get clogged with the mussels and have to be cleaned. These mussels also compete for the food that small fish eat, making it tougher for fish to thrive.
It is virtually impossible to eliminate a new species once it has been established in the lakes. It is surprisingly easy, though, to prevent their arrival in ballast tanks.