Zebra mussels were discovered in BBL in September of 2016. Their spread throughout the lake will determine how much damage they do to the body of water. The Big Birch Lake Association has worked intensely for years to prevent AIS from entering the lake but knew inevitably it would be the fate of this body of water too. The association continues to monitor the lake accesses during the summer to help prevent new species from entering the lake and zebra mussels from leaving to infest some other body of water. Unfortunately, there are worse invasive species than zebra mussels namely starry stonewort.