Introduction :
Craydids , also known as crawfish, craydids, crawdaddies, crawdads, freshwater lobsters, mountain lobsters, mudbugs are freshwater crustaceans resembling small lobsters
Taxonomically, they are members of the superfamilies Astacoidea and Parastacoidea.
Habitat:
The body of a decapod crustacean, such as a crab, lobster,
or prawn (shrimp), is made up of twenty 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.
Geographical distribution and classification
The three families of crayfish
Astacidae: Austropotamobius pallipes
Cambaridae: Procambarus alleni
Parastacidae: Cherax pulcher.
Crayfish as Bioindicators for Monitoring level of pollution and ClO2 :
Monitoring of Pollution :
The Protivin brewery in the Czech Republic uses crayfish outfitted with sensors to detect any changes in their bodies or pulse activity in order to monitor the purity of the water used in their product.
The creatures are kept in a fish tank that is fed with the same local natural source water used in their brewing.
If three or more of the crayfish have changes to their pulses, employees know there is a change in the water and examine the parameters.
Scientists also monitor crayfish in the wild in natural bodies of water to study the levels of pollutants there.
The research was conducted by :
Research Institute of Fish Culture and Hydrobiology, South Bohemian Research Center of Aquaculture and Biodiversity of Hydrocenoses,
Faculty of Fisheries and Protection of Waters,
University of South Bohemia in České Budejovice, , Czech Republic
The effect of long-term exposure of signal crayfish to different levels of ClO2 were investigated and assessed through the observation of heart rate, diurnal rhythm and mortality.
The study showed the changes in the heart rate of unstimulated spiny lobster and the ClO2 exposed signal crayfish were similar in the premolting period.
The heart rate of an unaffected lobster increased 1–2 h before molting to a peak of 80–120 bpm and declined about 15 min before the beginning of molting.
Food :
Crayfish are eaten worldwide. 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.
Bait :
Crayfish are preyed upon by a variety of ray-finned fishes,and are commonly used as bait, either live or with only the tail meat. They are a popular bait for catching catfish ,largemouth bass, smallmouth bass, striped bass,perch & pike.
Transporting crayfishes as live bait has also contributed to the spread of zebra mussels in various waterways throughout Europe and North America, as they are known to attach themselves to exoskeleton of crayfishes.
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, regular fish food, algae wafers, and small fish that can be captured with their claws.