Oyster River crayfish

I spent a morning at the Bear Creek Nature Park with friends, visiting the fish hatchery on the Oyster River. The river here meanders, sprawls through a wetland, branches out into hatchery channels and side streams. It's mostly shallow and dark, even as the overhead greenery turns yellow and rains down. In a muddy pool, we found a crayfish.

Signal crayfish (also crawfish, crawdad), Pacifastacus leniusculus. Under about 6 inches of water, competing with the reflections from trees overhead.

There is only one native crayfish species in BC – the Signal Crayfish (Pacifastacus leniusculus). This species can be identified by its uniform brownish coloration, white or light coloration of the claw joint, and the smooth surface of its carapace and claws compared to that of nonnative species. (Fishnbc)

They have a white to pale blue-green patch near the claw hinge [me: here it's blue-green], like the white flags that signalmen used for directing trains—hence the name. (Wikipedia)

This critter appeared to be about 3 inches long. (It's hard to be sure underwater because of the refraction.) We caught one in the Campbell River a few years ago; it was a bit bigger. They usually grow to about 3 1/2 inches, but can reach as much as 8 inches, given, I imagine, a healthy diet of leftovers and a long life. (Wikipedia) They can live as long as 20 years. Which I find amazing.