They're called signal crayfish. They are definitely larger than their US cousins. The folks that own the fishing pond are glad when I make an order. The crawfish are known to cut the fishing lines of folks bottom fishing.
Wikipedia:
"Members of this species are typically 6–9 cm (2.4–3.5 in) long, although sizes up to 16–20.32 cm (6.30–8.00 in) are possible.[3] They are bluish-brown to reddish-brown in colour, with robust, large, smooth claws. They have a white to pale blue-green patch near the claw hinge,[4] like the white flags that signalmen used for directing trains—hence the name."
