Crayfish, also known as crawfish, crawdads, freshwater lobsters, mountain lobsters, mudbugs or yabbies, are actually freshwater crustaceans resembling a smaller version of a lobster, to which they are related; taxonomically, they are members of the super families Astacoidea and Parastacoidea. They are small crustaceans that live in freshwater water habitats in which do not freeze over in cold conditions. Adult size is reached by crayfish in the wild in about 4 years. They can live from 20 to 30 years.
Crayfish are categorized by a joined head and thorax, or midsection, and a segmented body, which is sandy yellow, green, red, or dark brown in color. The head has a sharp snout, and the compound eyes are on movable stalks. The exoskeleton, or body covering, is thin but tough. The front pair of the five pairs of legs has large, powerful pincers (chelae). There are five pairs of smaller appendages on the abdomen, used mostly for swimming and circulating water for respiration. Their large anterior-most pairs of legs have powerful claws which are efficient tools for defense, food gathering, and object manipulation. Their four pairs of walking legs assist them in rapid locomotion across the bottom substrates of their aquatic habitats. Most adult crayfish are about 7.5 cm (3 inches) long. Among the smallest is the 2.5-cm-long Cambarellus diminutus of the southeastern United States and the largest is Astacopsis gouldi of Tasmania, which may reach 40 cm in length and weigh about 3.5 kg (8 pounds).
They breathe through feather-like gills. Some species are found in brooks and streams where there is running fresh water, while others thrive in swamps, ditches, and rice paddies. Crayfish feed on living and dead animals and plants. Rivers and brooks are the main living habitat for the crayfish due to their water clarity and thin ice conditions. Humans will rarely see crayfish during the day but if you shine a flashlight in the water at dark its a whole different story. These guys do their traveling and feeding during the darkest hours of the night. You will see them walking ever so slow to their destinations but when danger arises, the flap their strong tail and their gone in the blink of an eye.
History
Crayfish evolved from marine ancestors dating back some 280 million years. There are more than 300 species of crayfish worldwide, which are categorized into three families: the Astacidae, the Cambridae (found only in the Northern Hemisphere), and the Parastacidae. A few species have modified to tropical habitats, but most live in temperate regions. None occur in Africa or the Indian subcontinent, though one species is found in Madagascar. Crayfish live in water, hiding beneath rocks, logs, sand, mud, and vegetation. Some species dig burrows, constructing little chimneys from moist soil excavated from their tunnel and carried to the surface. Some terrestrial species spend their whole life below ground in burrows, emerging only to find a mate. Other species live both in their tunnels as well as venturing into open water. Many species live mostly in open water, retreating to their burrows during pregnancy and for protection from predators and cold weather.
Nutritional Value
Apart from their wonderful taste, cooked crayfish is a good source of nutrients, vitamins and minerals. Consuming 85 gram of cooked crayfish offers 2.64 µg of Vitamin B-12, 0.493 mg of Copper, 29.1 µg of Selenium, 14.89 g of Protein, 205 mg of Phosphorus, 0.94 mg of Iron, 1.26 mg of Zinc, 1.417 mg of Vitamin B3, 0.114 mg of Vitamin B6 and 0.435 mg of Vitamin B5. Moreover many Amino acids 0.207 g of Tryptophan, 0.601 g of Threonine, 0.72 g of Isoleucine, 1.18 g of Leucine, 1.295 g of Lysine, 0.42 g of Methionine and 0.167 g of Cystine are also found in 85 gram of cooked crayfish.
How to Eat
Like other edible crustaceans, only a small portion of the body of a crayfish is eaten.
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, other portions, such as the claw meat, may be eaten.
In France, dishes with a base or garnish of crayfish (écrevisse) are often described as à la Nantuaise.
Crayfish tails and butter are also used to flavor the Nantua Sauce commonly served with Quenelles.
Ma la flavored crayfish is shortened to “ma xiao” and is often enjoyed with beer in a hot mid-summer evening in Beijing.
Crayfish are a traditional seasonal appetizer that is used as an accompaniment to beer and liquor in Russia and Ukraine.
Russians rarely include crayfish into complex dishes and, unlike other cultures; they usually consume the entire crayfish, short of the shell and the antennae.
One traditional Swedish and Finnish practice is to eat crayfish with a vodka or akvavit chaser.
Other Facts
Crayfish are kept as pets in freshwater aquariums.
Smallest crayfish is the 2.5-cm-long Cambarellus diminutus of the southeastern United States.
Largest is Astacopsis gouldi of Tasmania, which may reach 40 cm in length and weigh about 3.5 kg (8 pounds).
Tips
Crayfish are territorial. Keeping multiple crayfish in one tank is not suggested. Do not keep them with fish small enough for them to eat or fish big enough to eat them.
Crayfish in captivity typically live only about 2-3 years, but with proper treatment they can live to 7-8 years.
Crayfish that are old will feed at night and the younger ones feed during the day.
Crayfish outgrow their exoskeleton from time to time and shed it in a process called molting. The hard protective shell will split down the back and the crayfish will emerge. When crayfish shed their exoskeleton, they are extremely vulnerable and will look for a place to hide. Provide sufficiently of cover and remove all predatory creatures (including large snails and aggressive fish). Do not handle your crayfish until a new exoskeleton is fully developed (about one week).
Crayfish love the dark so put them in the dark whenever you can.
Avoid using cat food or any canned fish products. Canned fish is high in salt and preservatives and is actually more expensive than a three dollar container of shrimp pellets that would last a single crayfish more than a year.
Leave the crayfish in a dark shady space.
Crayfish also like caves, if you can, get a small cave for your aquarium.
If you want to breed crayfish, be very careful. You will have to find one that does not fight with other one and interacts well.
Crayfish will walk backwards and raise their claws if threatened.
Warnings
When you are transporting the crayfish via car, truck, or bus, be sure not to move it around too much. This could result in what some people call “crayfish soup.” This may sound funny, but it is a serious term that can cause your crayfish to become over stressed and extremely confused. Some certain salt water crayfish are more prone to this than most others. Be careful!
Make sure that if you are keeping a crayfish never keep them out of the aquarium no matter what unless you’re cleaning the tank.
Don’t pick the crayfish up near its eyes or tail! If you do that, you might get pinched.
Few things you didn’t know about crayfish
Crayfish have blue blood.
Crayfish do not walk backwards, however they can swim backwards by flapping their tail.
The male crayfish has two extra legs under his belly.
Signal crayfish have a pale patch near the claw hinge.
