Astacus astacus (L. 1758)
Synonyms: Cancer astacus, Astacus fluviatilis, Potamobius fluviatilis
Common names: Noble crayfish (English), Edelkrebs (German), écrevisse à pieds rouges (French)
Superior taxa: `Astacidae´ < Astacoidea < Astacida < Decapoda
The Noble crayfish is the largest crayfish species native to Central Europe and was once widely distributed and abundant in low- and mid-elevation streams and lakes with moderate temperatures. During the last 140 years, Noble crayfish have largely disappeared from their natural prime habitats because of crayfish plague, water pollution and spread of alien crayfish. Isolated lentic habitats, in particular artificial habitats, such as gravel pit lakes, constitute now important refuges for Noble crayfish in Central Europe.
Distribution map: dots indicate confirmed presence in 50x50 km CGRS grid cells and the red area shows the probable natural distribution range. Principal data source: Souty-Grosset et al. (2006) and Kozak et al. (2013), and citations therein.
IUCN conservation status: Vulnerable
Prime habitat: low- to mid-elevation streams and lakes with summer temperatures above 15 °C
Size (total body length): 15 cm, rarely up to 20 cm
Age at maturity: 2 to 5 years, depending on water temperatures and sex (males may mature earlier than females)
Longevity: approx. 10 years
Fecundity: up to approx. 250 pleopodal eggs
Key identification characters: First pleopod very prominent in males, in females smaller than the subsequent pleopods. Males without any hooks on the ischia of the pereiopods. Females without annulus ventralis. No prominent spine on the inner margin of the carpus of the chela (a row of smaller spines may be present). Two pairs of postorbital ridges. Cervical spines present. Rostrum flat, rostral cresta media prominent with denticulation (formed by visible spines). Rostral borders parallel or trapezoid. Chela compact, surface granulation big and rough. Inner margin of the fixed side of the chela (propodus) with an indentation limited by two tubercles.
Head view of a Noble crayfish. Key characters are highlighted in color.
Coloration: Dorsal coloration usually dark brown, but highly variable from blue-grey to greenish, reddish, and almost black. Rarely pure blue. Small red spot on the dorsal side of the chela joint. Ventral sides of the chelae and pereiopods reddish. Juveniles with dark spots on the carapace and orange chelae tips.
Main references and further reading
- Füreder, L., (Ed.) (2009). Flusskrebse: Biologie, Ökologie, Gefährdung. Veröffentlichungen des Naturmuseums Südtirol 6, Folio Verlag, Bozen, Wien, 144 p. ISBN: 9783852564067 (in German)
- Souty-Grosset, C., Holdich, D.M., Noel, P.Y., Reynolds, J.D., Haffner, P. (Eds.) (2006). Atlas of Crayfish in Europe, Museum national d`Histoire naturelle, Paris, 187 p. ISBN: 2856535798