St. Paul, MN (MNN)  --  The Minnesota Department of Natural Resources has a powerful weapon in its effort to stop the spread of invasive zebra mussels.  They have been found in at least eight Minnesota lakes this summer.

The D-N-R is using two zebra mussel sniffing dogs and boat launch check points.  One of them, Brady, was checking boats and trailers going in and out of Lake Independence Saturday.  Any time Brady smells a zebra mussel he immediately sits, then gets a reward.  His handler, Julie Siems, says he is a good educational tool, as well.