Noble crayfish (Astacus astacus)

loading
Noble crayfish portrait
loading
Loading more images and videos...

Noble crayfish fact file

Noble crayfish description

KingdomAnimalia
PhylumArthropoda
ClassCrustacea
OrderDecapoda
FamilyAstacidae
GenusAstacus (1)

This crustacean varies in colour from green or blue to brown and sometimes black. The undersides of the claws are dark red (2). The head and internal organs of all crayfish are protected by the carapace and the six segments of the abdomen are individually encased with a flexible membrane between them to allow movement. Crayfish have a pair of large claws at the front end, followed by four pairs of walking legs and then four pairs of small swimming legs called swimmerets. These swimmerets are covered with fine hairs to which the female attaches her eggs. A central tail flap is surrounded by four other flaps that are used to move the crayfish rapidly through the water, as well as curling up to form a brood chamber. There are two eyes on the end of eyestalks, but the senses of touch and taste are far more important, and are perceived using a pair of large feelers (or antennae) and a pair of small, fine, centrally located feelers (or antennules).

Also known as
Broad-fingered crayfish, European crayfish.
French
Écrevisse á Pattes Rouges, Écrevisse Fluviatile, Écrevisse Noble.
Size
Length of male: 16 cm (2)
Length of female: 12 cm (2)
Top

Noble crayfish biology

Feeding at night on worms, aquatic insects, molluscs and plants, the noble crayfish spends the day resting in a burrow. It undergoes periodic moults, shedding the hard exoskeleton in order to grow slightly larger, and then forming a new shell. Sexual maturity is reached during the fourth year of life, and breeding takes place between October and November. The fertilised eggs are carried by the female, attached to her legs, over the winter until May, when they hatch and disperse. Both juvenile and adult noble crayfish are preyed upon by mink, eel, perch, pike, otter, and muskrat (2).

Top

Noble crayfish range

Previously prolific throughout Europe, the noble crayfish now has a scattered distribution through northern Europe and western Russia (1) (2).

Top

Noble crayfish habitat

A freshwater invertebrate, the noble crayfish is found along the banks of well oxygenated streams, rivers, lakes and ponds (2).

Top

Noble crayfish status

The noble crayfish is classified as Vulnerable (VU) on the IUCN Red List (1). It is listed under Appendix III of the Berne Convention on the Conservation of European Wildlife and Natural Habitats (3) and on Annex V of the EC Habitats Directive (4).

IUCN Red List species status – Vulnerable

Top

Noble crayfish threats

Considered to be the finest edible crayfish, the noble crayfish was once abundant in Europe, but was expensive to buy. The American ‘signal crayfish’ (Pacifastacus leniusculus) was introduced to European waterways as a cheaper alternative, but the presence of this species was to have disastrous effects on the noble crayfish. An outbreak of crayfish plague, carried by the signal crayfish, spread through populations of all of Europe’s Astacus species. Caused by the freshwater fungus Aphanomyces astaci, crayfish plague infects and kills the noble crayfish, leaving the resistant signal crayfish unharmed (3).

Dredging of waterways has further threatened Astacus crayfish species as it leaves the water cloudy and disturbs the habitat. Acid rain, also causing a decrease in water quality, is thought to be responsible for a decline in breeding success, as the egg cases of young crayfish are unable to form properly (2).

Top

Noble crayfish conservation

Efforts to reintroduce the noble crayfish have been hindered by the presence of the signal crayfish, which competes for food resources, although in Norway some recent reintroductions look promising (5). In most European countries limits have been set for the trapping of noble crayfish, including restricting trapping to a period of about three months, and setting a minimum crayfish length of 10 cm. In some areas, trapping is completely prohibited. Elimination, or at least reduction, of signal crayfish populations, and protection of crayfish habitat are required to allow the noble crayfish to recover (2).

View information on this species at the UNEP World Conservation Monitoring Centre.
Top

Authentication

This information is awaiting authentication by a species expert, and will be updated as soon as possible. If you are able to help please contact: arkive@wildscreen.org.uk
Top

Glossary

Abdomen
In arthropods (crustaceans, insects and arachnids) the abdomen is the hind region of the body, which is usually segmented to a degree (but not visibly in most spiders). In crustacea (e.g. crabs) some of the limbs attach to the abdomen; in insects the limbs are attached to the thorax (the part of the body nearest to the head) and not the abdomen. In vertebrates the abdomen is the part of the body that contains the internal organs (except the heart and lungs).
Antennae
Pair of sensory structures on the head of invertebrates.
Carapace
The top shell of a turtle. In arthropods (insects, crabs etc), the fused head and thorax (the part of the body located near the head) also known as ‘cephalothorax’.
Exoskeleton
The horny shell-like skeleton that encloses the body of all Arthropoda.
Invertebrate
Animals with no backbone.
Reintroduction
Putting an animal or plant into an area where the species or sub-species previously lived but from which they are locally extinct - usually referring to projects aiming to re-establish self-perpetuating populations.
Top

References

  1. IUCN Red List (September, 2008)
    http://www.iucnredlist.org
  2. Well, S.M., Pyle, R.M. and Collins, N.M. (1983) The IUCN Invertebrate Red Data Book. IUCN, Gland, Switzerland.
  3. Berne Convention (February, 2005)
    http://www.jiwlp.com/contents/bern.pdf
  4. EC Habitats Directive (February, 2005)
    http://www.jncc.gov.uk/page-1374
  5. Taugbøl, T. (2004) Reintroduction of noble crayfish Astacus astacus after crayfish plague in Norway. Bulletin Francais de la Peche et de la Pisciculture, 372(373): 315 - 328.
X
Close

Image credit

Noble crayfish portrait  
Noble crayfish portrait

© P. Morris / www.ardea.com

Ardea wildlife pets environment
59 Tranquil Vale
London
SE3 0BS
United Kingdom
Tel: +44 (0) 208 318 1401
ardea@ardea.co.uk
http://www.ardea.com

X
Close

Link to this photo

ARKive species - Noble crayfish (Astacus astacus) Embed this ARKive thumbnail link ("portlet") by copying and pasting the code below.

Terms of Use - The displayed portlet may be used as a link from your website to ARKive's online content for private, scientific, conservation or educational purposes only. It may NOT be used within Apps.

Read more about

X
Close

MyARKive

MyARKive offers the scrapbook feature to signed-up members, allowing you to organize your favourite ARKive images and videos and share them with friends.

Play the Team WILD game:

Team WILD, an elite squadron of science superheroes, needs your help! Your mission: protect and conserve the planet’s species and habitats from destruction.

Conservation in Action

Which species are on the road to recovery? Find out now »

Help us share the wonders of the natural world. Donate today!

Blog