crayfish

Astacoidea
 

The study of crayfish is called astacology .

The anatomy of crayfish may be found in the article "decapod anatomy".

Names

The name "crayfish" does not derive from the word "fish", but rather from the Old French word escrevisse (Modern French écrevisse) from Old Frankish *krebitja (cf.

In New Zealand the name crayfish (or cray) refers to a spiny lobster, and crayfish are called freshwater crays or koura, the Māori name for the animal.

Some kinds of crayfish are known locally as lobsters, crawdads , mudbugs  In the Eastern United States, "crayfish" is more common in the north, while "crawdad" is heard more in central regions, and "crawfish" further south, although there are considerable overlaps .

Geographical distribution and classification

There are three families of crayfish, two in the northern hemisphere and one in the southern hemisphere.

The greatest diversity of crayfish species is found in south-eastern North America, with over 250 species in nine genera, all in the family Cambaridae.

Australasia is another centre of crayfish diversity, with over 100 species in a dozen genera. Many of the better-known Australian crayfish are of the genus Cherax, and include the marron (Cherax tenuimanus), red-claw crayfish (Cherax quadricarinatus), yabby (Cherax destructor) and western yabby (Cherax preissii).

Madagascar has a single (endemic) crayfish species, Astacopsis madagascarensis.

Europe is home to seven species of crayfish in the genera Astacus and Austropotamobius.

Moulting in crayfish

Crayfish also need to moult as they grow because their hard exoskeletons do not allow much room for expansion. The first few days after a moult, a crayfish's skin is very soft and it is very vulnerable to attacks from other animals and crayfish.

When the crayfish is ready to moult, it will try to find a hiding spot.

The freshly moulted crayfish will invariably be larger as part of the growing process, but is vulnerable on several fronts.

Crayfish as a dish

Crayfish are eaten in Europe and China, but they are perhaps most popular in the U.S. state of Louisiana, where the standard culinary term is crawfish;

Crayfish is a popular dish in Sweden and Finland, and is by tradition primarily consumed during the fishing season in August.

The Mexican crayfish is named locally as Acocil and was a very important nutrition source of the ancient Mexican Aztec culture;

Crayfish's recent culinary popularity swept across China in the late 1990s, featuring its Ma La (a combine flavor of Sichuan pepper and hot chilli) flavor.

Crayfish as pets

Crayfish are sometimes kept as pets in freshwater aquaria. In nations where imported alien crayfish are a danger to rivers, such as England, crayfish spread because specimens captured for aquariums from one river are often flung back into a different one.

Crayfish plague

Some crayfish suffer from a disease called crayfish plague.