crayfish

The spiny lobster, excessively called crawfish or crawdad, is a brisk irrigate spineless that declinations in the Kingdom Animalia. They be arthropods that endure to the largest crustacean recite, the Decapoda, and atomic number 18 related to the brine lobster. This order constitutes the families Astacidae ( northerlyern Hemisphere), Parastacidae, or Austroastracidae (S let outhern Hemisphere). There be legion(predicate) assorted genera of the crawdaddy put all everywhere the world. The to a great extent or less common genera of North the States accommodate Procambarus, Orconectes, Faxonella, genus Cambarus, Camb atomic number 18llus, and Pacifastacus. The most probable ecrevisse to be set in motion at Rice Creek would be the Cambarus robustus. Austropotamobius is the most common genus of Europe.         crawdad occur in a wide-cut mannequin of fresh water habitats and ar (or were) naturally widespread in all continents of the world exce pt Antarctica and, surprisingly, Africa (Sutcliffe, 2002, p297). There argon to a greater extent than 500 species of crayfish, more than half of which occur in North America alone. ecrevisse are also suffer in Europe, New Zealand, and East Asia. These creatures are nocturnal so they befog in mud burrows or under rocks and infiltrate detritus during the day and they search for food at night. Their nutrition at Rice Creek, as well as almost the world, includes snails, oligochaetes, humiliated fish; such as minnow, guppies, and goldfish; aquatic insects, aquatic plants, and dead or decaying organisms. The crayfish is the largest mobile macroinvertebrate in equable freshwater ecosystems (Holdich & Lowery, 1988, p.1). Crayfish are unremarkably 3-4 inches in continuance. The smallest crayfish, Cambarellus diminutus are about 1 inch long and are found in the southeastern United States. Astacopsis gouldi on the opposite pot is one of the largest found in Tasmania which has a length of 40 cm (15 inches) and has a! weight of about 3.5 kg (8 pounds) (Daniel, 2002). The cylindrical-shaped ashes of the crayfish is covered by a thick exoskeleton, which molts take hold of it grows. There are advantages and disadvantages to having an exoskeleton. The exoskeleton protects the animal from early(a) crayfish and predators alike trout and bass, but when it is molted the animal is very vulnerable until the new exoskeleton hardens. more or less other predators include eels, pike, chub, perch, herons, mink, otters, snakes, and people. The crayfish is usually characterized by having a head attached to the thorax, which is called a cephalothorax. The cephalothorax is so connected to the abdomen, which is connected to segmented tail. The abdomen is approxi helpmately cardinal percent of the buckler length (Hobbs, 1987, p.31). The tail can be used to quickly dart backward if threatened. On the cephalothorax on that point are deuce compound eyes, which are attached to assignable stalks. T hese stalks help the animal protect its eyes by retracting them if riskiness approaches. The crayfish also has a pointy nose and a conform to of sensory antennae on its head. There are four pairs of go legs attached to the thorax. asunder from walking backwards, forwards, and sideways, these legs help the animal investigation food in crevices among rocks. Crayfish also fork out a pair of strong pinchers, which are very implemental in raw and capturing food, as well as defense. They beget five pairs of swimmerets that are located under the abdomen; bailers, which are used to clog up water over the gills; and some(prenominal) specialized, food-handling legs. All of the legs on a crayfish can regenerate, or grow back if lost. Crayfish have been known to acclaim in a variety of colors including green, sandy yellow, pink, snow-clad or dark brown. Crayfish have a animation expectancy of about 2 years and rely on mass reproduction for the subsequence of the species( Daniel, 2002). Crayfish reproduce sexually and mate ! in fall through winter. A apelike attracts a female by touching her with his antennae and his claws. He whence turns the female on her back, holds her pinchers in his, and then positions his abdomen over hers. He continues to insert the ischial hooks on his pereiopods into coxal membranes of the pereiopods of the female (Page, 1985, p.343). This is essentially the way in which the crayfish are locked together to mate. by and by the sperm is in the female, the male injects a plug in her so other males wint try to mate with her.

When the eggs are fertilized, she glues them to her swimmerets and then finds a safe place to stay. After a fewer weeks, hatching takes place and the nipper crayfish stay with their mommy for weeks before going out on their own. Crayfish are important to the environment and turning a very epoch-making role in their ecosystems. Since they are omnivorous, they process organic question and transform capacity between different levels of the food chain. Their biomass is extravagantly in comparison with other consumers(Holdich & Lowery, 1988, p.128). Most animals cannot readily implement detritus and living botany and so they transfer energy from the producer directly to high trophic organisms. They are practically referred to as rubbish collectors because they change waste into protein. Over the years, over-fishing, water pollution, irrigation demand, and disease has decreased the tribe of these important animals. Man is accordingly negatively affecting the freshwater ecosystem. There are many efforts being made by conservation biologists and Fish and Wildlife do ecosystem teams to stop the de! duction of crayfish throughout the world. Bibliography Butler, S.R., DiStefano, R.J., Schuster, G.A. (2003). Crayfish: an overlook fauna. Endangered Species Bulletin, 28, 2, 10-13. Daniel, P. (2002). Crayfish Background. Retrieved October 10, 2003, from Hofstra University tissue site: http://people.hofstra.edu/ force/peter_c_daniel/Animal_Physiology/special_topics_spring2002/Ken/Topic_1.html Hobbs, H.H. (1987). A review of the crayfish genus Astacoides (Decopoda: Parastacidae). Wahsington, D.C: Smithsonian Institution Press. Holdich, D.M.,&Lowery, R.S.(1988). freshwater crayfish: biology, management, and exploitation. Potland, Oregon: Timber Press. Page, L.M. (1985). The crayfishes and shrimps (Decapoda) of Illinois. Champaigne, Illinois: University of Illinois Press. Sutcliffe, D. (2002). biological science of freshwater crayfish. Fisheries Research, 59,1,297-299. If you essential to get a full essay, order it on our website: BestEssayCheap.com

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