Fresh Water Crustacean

We discovered this little guy a couple of weeks ago on our first trip to the cottage. There was still snow on the ground so we had to hike in.



It was in about a foot of icy water on the edge of the lake, dead but perfectly preserved. About the size of my hand, it has deep blue claws that seem almost too big for its prawn like body. I've been going to this lake my entire life but have never seen one before.

Freshwater rock lobster? Super claw prawn lobster? Crayfish?

Can anyone put a name to this thing?