Everything about Crawfish totally explained
» For the marine crustaceans commonly known as crayfish, see spiny lobster.
Crayfish,
crawfish, or
crawdads, are
freshwater crustaceans resembling small
lobsters, to which they're closely related. They breathe through feather-like
gills and are found in bodies of water that don't freeze to the bottom; they're also mostly found in brooks and streams where there's fresh water running, and which have shelter against predators. Most crayfish can't tolerate
polluted water, although some species such as the
invasive Procambarus clarkii are more hardy. Some crayfish have been found living as much as 3
m (10
feet) underground.
In
Australia and
New Zealand, the name
crayfish (or
cray) generally refers to a saltwater
spiny lobster, of the type
Jasus that's indigenous to much of southern
Oceania, whilst the
freshwater species are usually considered a
yabby, or a
koura, from the
Aboriginal, and
Māori, names for the animal.
The study of crayfish is called
astacology .
Names
The name "crayfish" comes from the
Old French word
escrevisse (
Modern French écrevisse) from
Old Frankish *
krebitja (cf.
crab), from the same root as
crawl. The word has been modified to "crayfish" by association with "fish" (
folk etymology). The largely
American variant "crawfish" is similarly derived.
Some kinds of crayfish are known locally as
lobsters,
crawdads ,
mudbugs .
Anatomy
The body of a
decapod crustacean, such as a crab, lobster, or prawn, is made up of nineteen
body segments grouped into two main body parts, the
cephalothorax and the
abdomen. Each segment may possess one pair of
appendages, although in various groups these may be reduced or missing. A crayfish is usually 7.5 centimeters long, but may grow larger.
Geographical distribution and classification
There are three families of crayfish, two in the
northern hemisphere and one in the
southern hemisphere. The southern-hemisphere (
Gondwana-distributed) family
Parastacidae lives in
South America,
Madagascar and
Australasia, and is distinguished by the lack of the first pair of
pleopods . Of the other two families, members of the
Astacidae live in western
Eurasia and western
North America and members of the family
Cambaridae live in eastern
Asia and eastern
North America.
The greatest diversity of crayfish species is found in south-eastern
North America, with over 330 species in nine genera, all in the family
Cambaridae. A further genus of
astacid crayfish is found in the
Pacific Northwest and the headwaters of some rivers east of the
Continental Divide.
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). The world's largest crayfish,
Astacopsis gouldi, which can achieve a mass in excess of 3
kilograms, is found in the rivers of northern
Tasmania.
Madagascar has a single (
endemic) crayfish species,
Astacopsis madagascarensis.
Europe is home to seven species of crayfish in the genera
Astacus and
Austropotamobius.
Cambaroides is native to
Japan and eastern mainland Asia.
Crayfish as a dish
Crayfish are eaten in
Europe,
China,
Africa,
Australia and the
United States. 98% of the crayfish harvested in the United States come from Louisiana, where the standard culinary terms are
crawfish or
écrevisses.
Louisiana crawfish are usually boiled live in a large pot with heavy seasoning (salt, cayenne pepper, lemon, garlic, bay leaves, etc.) and other items such as
potatoes,
maize,
onions,
garlic, and
sausage. They are generally served at a gathering known as a
crawfish boil. Other popular dishes in the
Cajun and
Creole cuisines of Louisiana include crawfish
étouffée, crawfish pie, crawfish dressing, crawfish bread, and crawfish beignets , and crayfish are an ingredient in
Chicken Marengo.
A common myth is that a crawfish with a straight tail died before it was boiled.
Crayfish is a popular dish in
Scandinavia, and is by tradition primarily consumed during the fishing season in August. The boil is typically flavoured with
salt,
sugar,
ale, and large quantities of the flowers of the
dill plant. The catch of domestic freshwater crayfish,
Astacus astacus, and even of a transplanted American species,
Pacifastacus leniusculus, is very limited and to satisfy demand the majority of what is consumed has to be imported. Sales depended on imports from
Turkey for several decades, but after a decline in supply,
China and the
United States are today the biggest sources of import.
The Mexican crayfish is named locally as
acocil and was a very important nutrition source of the ancient Mexican
Aztec culture; now this kind of crayfish is consumed (mainly boiled) and prepared with typically Mexican sauces or condiments in central and southern Mexico.
In China, the culinary popularity of crayfish swept across Mainland China in the late 1990s. Crayfish is generally served with
Mala flavour (a combined flavour of Sichuan pepper and hot chili) or otherwise plainly steamed whole, to be eaten with a preferred sauce. In
Beijing, the
Ma La flavoured crayfish (麻辣小龙虾) is shortened to "Ma Xiao" (麻小) and is often enjoyed with beer in a hot mid-summer evening.
Like other edible crustaceans, only a small portion of the body of a crayfish is edible. In most prepared dishes, such as soups, bisques and étouffées, only the tail portion is served. At crawfish boils or other meals where the entire body of the crayfish is presented, however, other portions may be eaten. Claws of larger boiled specimens are often pulled apart to access the meat inside. Another favourite is to suck the head of the crayfish, as seasoning and flavour can collect in the fat of the boiled interior. A popular
double entendre laden phrase heard around crawfish season in Louisiana derives from this practice: "Suck the head, pinch the tail" .
Crayfish as pets
Crayfish are kept as pets in freshwater aquariums. They prefer foods like shrimp pellets or various vegetables but will also eat tropical fish food, algae wafers, and even small fish that can be captured by their claws, such as
goldfish or
minnows. Their disposition towards eating almost anything will also cause them to consume most aquarium plants in a fish tank; however, crayfish are fairly shy and may attempt to hide under leaves or rocks. When keeping a crayfish as a pet, one must provide a hiding space. At night, some fish become less energetic and settle to the bottom. The crayfish might see this as a chance for an easy meal, or a threat, and injure or kill the fish with its claws. Crayfish are effective scavengers and will consume fish carcasses. They sometimes will consume an exoskeleton after it's moulted. Since crayfish are accustomed to being around ponds or rivers that'll have a tendency to shift gravel around on the bottom of your tank, creating mounds or trenches to emulate a burrow. Crayfish are great
escape artists and will try to climb out of the tank, so any holes in the hood should be covered.
However, most species of dwarf crayfish, such as
Cambarellus patzcuarensis won't destructively dig or eat live aquarium plants. They are also relatively non-aggressive and can even be kept safely with
dwarf shrimp. Because of their very small size of 1.5 inches or less, some fish, such as
loaches are often a threat to the crayfish than the other way around.
In some nations, such as
England,
United States,
Australia, and
New Zealand, imported alien crayfish are a danger to local rivers. The three species commonly imported to Europe from the Americas are
Orconectes limosus,
Pacifastacus leniusculus and
Procambarus clarkii.
Crayfish may spread into different bodies of water because specimens captured for pets in one river are often flung back into a different one. There is a potential for ecological damage when crayfish are introduced into nonnative bodies of water.
Crayfish plague
Some crayfish suffer from a disease called
crayfish plague. This is caused by the
water mould Aphanomyces astaci. Species of the genus
Astacus are particularly susceptible to infection, allowing the more resistant
signal crayfish to invade parts of
Europe. Crayfish plague isn't indigenous to Europe, rather it was introduced by the incorporation of new species of crayfish from the Americas.
Further Information
Get more info on 'Crawfish'.
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