Muskrat activity increases on Floating platforms

In the Fall of 2014, fresh water mussel shells were observed in piles one of the floating platforms. Some of the shells exhibited bite marks and broken pieces and some of the shells were just separated into two halves.
The motion activated cameras have captured new images of muskrats using the platforms in this Fall of 2015.
Among the interesting behaviors observed in the images, the muskrats can be seen bringing mussel shells and working to open them, and leaving empty shells behind.

Muskrats are known to eat yellow water lilies and over the last couple weeks, the northern end of Silver lake, which had a large number of water lily flower heads, now has just stems. Something has taken the flower heads and left behind just bare stems.
There were hundreds of pictures captured over the last week, and up to three (3) muskrats at a time are observed on the platforms.