Signal Crayfish are indigenous to Western North America and in the peaceful waters of Morrison Creek can reach a decent size. Photo by Jim Palmer

Signal Crayfish are indigenous to Western North America and in the peaceful waters of Morrison Creek can reach a decent size. Photo by Jim Palmer

Crayfish are represented in BC by a single native species, Pacifastacus leniusculus, with three subspecies. These are restricted to freshwater ponds, lakes, rivers, and streams.

Miniature Signal Crayfish.  Photo by K Clouston

Miniature Signal Crayfish. Photo by K Clouston

The signal crayfish is native to North America west of the Rocky Mountains, in BC, Washington, Oregon, and Idaho.  The crayfish found in BC belong to a small family that includes Pacifastacus as well as the native European crayfish, Astacus.  Both crayfish and lobsters are omnivores, feeding on nearly anything they encounter.

Members of this species are typically 6–9 centimetres (2.4–3.5 in) long, although sizes up to 16–18 cm (6.3–7.1 in) are possible. 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, like the white flags that signalmen used for directing trains—hence the name.

Around 200–400 eggs are laid after mating in the autumn, and are carried under the female’s tail until they are ready to hatch the following spring. The eggs hatch into juveniles, which pass through three moults before leaving their mother. Sexual maturity is reached after 2 or 3 years, and they can live up to 20 years.

This is how you might spot them as they trundle along the creek bottom. Photo by K. Clouston

This is how you might spot them as they trundle along the creek bottom. Photo by K. Clouston