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freshwater crustaceancrustacean
, primarily aquatic arthropod of the subphylum Crustacea. Most of the 44,000 crustacean species are marine, but there are many freshwater forms. The few groups that inhabit terrestrial areas have not been particularly successful in an evolutionary sense; most require
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 smaller than but structurally very similar to its marine relative the lobsterlobster,
marine crustacean with five pairs of jointed legs, the first bearing large pincerlike claws of unequal size adapted to crushing the shells of its prey. The segmented body of the lobster consists of a large cephalothorax (made up of 14 segments) and a moveable, muscular
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, and found in ponds and streams in most parts of the world except Africa. Crayfish grow some 3 to 4 in. (7.6–10.2 cm) in length and are usually brownish green; some cave-dwelling forms are colorless and eyeless. They are scavengers, feeding on decayed organic matter and also on small fish. The swamp crayfish digs a burrow up to 3 ft (91 cm) deep with a water-filled cavity at the bottom in case of drought. The eggs develop while attached to the swimming legs of the female and look like miniature adults when hatched. Although crayfish are not eaten in most parts of the United States, they are consumed in areas in the Mississippi River basin and are used in the Louisiana area in a thick soup called crayfish bisque. They are agricultural pests in the Mississippi Delta area, where they feed on sprouting wheat and corn. A red-clawed species is considered a delicacy in Europe. Crayfish are classified in the phylum ArthropodaArthropoda
[Gr.,=jointed feet], largest and most diverse animal phylum. The arthropods include crustaceans, insects, centipedes, millipedes, spiders, scorpions, and the extinct trilobites.
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, subphylum Crustacea, order Decapoda.



an invertebrate of the order Decapoda. The body length is usually 6–30 cm, but some species, such as the Madagascar crayfish, reach a length of 80 cm. Most crayfishes inhabit freshwaters. They are nocturnal animals and hide in their burrows during the day. Crayfishes feed primarily on aquatic vegetation growing near the shore, but occasionally they feed on animal substances. The males are longer than the females and have more powerful claws. Crayfishes reproduce in the fall, after the females molt. The females carry from 50 to 100 eggs on their abdomen.

There are three families of crayfishes, distributed in temperate zones throughout the world, excluding Africa. Eight species of the family Astacidae are found in the USSR, with Astacus leptodactylus and A. astacus having the greatest commercial value. Approximately 90 percent of the entire catch of crayfishes in the USSR is from the basin of the Sea of Azov and the Baltic Sea.


Budnikov, K. N., and F. F. Tret’iakov. Rechnye raki i ikh promysel. Moscow, 1952.
Ivanov, A. V. Promyslovye vodnye bezpovonochnye. Moscow, 1955.


(invertebrate zoology)
The common name for a number of lobsterlike fresh-water decapod crustaceans in the section Astacura.


(esp US), crawfish
1. any freshwater decapod crustacean of the genera Astacus and Cambarus, resembling a small lobster
2. any of various similar crustaceans, esp the spiny lobster
References in periodicals archive ?
The white-claw, the UK's only native crayfish, is an important indicator of good water quality as they are sensitive to pollution.
The adaptability of the marbled crayfish has made it a pest species in many places (for a species that evolved in an aquarium, it would likely be a pest wherever it went), and it has already spread from Germany to as far as Sweden, Japan and Madagascar.
Researchers have been surprised by the marbled crayfish's reproductive success and remarkable adaptability, with genetically identical crayfish now thriving in the wild in diverse habitats from subtropical Madagascar to Sweden, Japan and German cities including Hanover and Heidelberg.
In Mr McKays case, he was involved in selling crayfish illegally in Tauranga in January this year.
The noble crayfish is of commercial interest for aquaculture and for restocking measures, including production in recirculating aquaculture systems (RAS), but effectively formulated diets are lacking to reach commercial production levels.
DNA testing was used to identify Crayfish Plague when dead specimens were reported in the river this month.
A voracious predator, the signal crayfish will eat almost anything it finds including plants, invertebrates, snails, small fish and fish eggs.
deanae collected in 2013, and our sampling protocols may not have been adequate to determine crayfish density.
Although the marination technology is well developed for meat, poultry, and fish industries, no information is yet available in the literature about preservative effects of rosemary and thyme essential oils (EOs) on marinated crayfish (Sallam et al.
In the same tank is also a medium sized crayfish, a smallish squeaker, and an exotic "mud sucker" type fish.
It is bigger and more aggressive than the native white-clawed crayfish and has eradicated the latter from many rivers.