I have seen them in the stream that comes out of Burnaby lake. I ride the bike trail(between Gaglardi and North Rd.) that goes along side that stream looking for driftwood once in a while & have seen them in there.
When I was a kid we used to fish them out of a small arm of the salmon river that runs through Forest Knoles in Langley/Fort Langley. We just tied meat to fishing line and then when the cray grabbed it we whipped them out of the water, crude but effective, good kicks too...well not for the crayfish I guess.