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Pacifastacus leniusculus
Common name(s):
Signal Crayfish
Size:
Up to 15 cm in length, from tip of rostrum to end of telson.
Identification:
Bluish/brown to reddish/brown in color. Muscular, large smooth claws. White patch near claw hinge.
Food:
P. leniusculus is an opportunistic generalist feeding polytrophically on aquatic plants, terrestrial plants, algae, carrion, insects, fish eggs,live fish and snails.
Range:
British Columbia, California, Idaho, Nevada, Oregon, Utah, and Washington. Introduced into Sweden, Finland, Great Britain and Japan.
Habitat:
Rivers, streams and lakes.
Misidentification:
Red Swamp Crayfish (Procambarus clarkii) the carapace is dark red bordering on black, and there is with a wedge-shaped stripe on the abdomen. Introduced populations of red swamp crayfish have been found in the King County area.
Life History:
Mating occurs in the fall and females carry the fertilized eggs on the underside of the abdomen for 7 to 8 months. In the spring when the eggs hatch the babies (identical to the adult form only smaller) stay with the mother until their second molt. After the second molt they leave the mother and start to feed on the same foods as the mother. During the first year an individual may triple in size. At age three or four they become sexually mature. Some individuals can live up to ten years.
Predators:
Raccoons, Fish, Birds, Rats, Otters, etc.
Additional Resources:
Suggested Reading:
Covich, Alan P. , and James H. Thorp, ed. Ecology and Classification of North American Freshwater Invertebrates. San Diego: Academic Press, 1991.
Last updated Thursday, August 24, 2006, by Lisa Ferrier
