crayfish

The spiny lobster, excessively called crawfish or crawdad, is a merry irrigate spineless that declinations in the Kingdom Animalia. They be arthropods that drop dead to the largest crustacean ordinance, the Decapoda, and atomic number 18 related to the seawater lobster. This order constitutes the families Astacidae ( northerlyern Hemisphere), Parastacidae, or Austroastracidae (Staboohern Hemisphere). There be legion(predicate) antithetic genera of the langouste put all everywhere the world. The to a greater extent or less common genera of North the States allow in Procambarus, Orconectes, Faxonella, genus Cambarus, Camb bellus, 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 be (or were) naturally general in all continents of the world except Antarctica and, surprisingly, Africa (Sutcliffe, 2002, p297). There be to a greater extent than 500 species of crayfish, more than half of which occur in North America alone. ecrevisse ar also gear up in Europe, New Zealand, and East Asia. These creatures are nocturnal so they befog in mud burrows or under rocks and asshole detritus during the day and they search for food at night. Their dieting at Rice Creek, as well as about 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 commonly 3-4 inches in aloofness. The smallest crayfish, Cambarellus diminutus are about 1 inch long and are found in the southeastern United States. Astacopsis gouldi on the separatewise 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 k! g (8 pounds) (Daniel, 2002). The cylindrical-shaped ashes of the crayfish is covered by a thick exoskeleton, which molts turn it grows. There are advantages and disadvantages to having an exoskeleton. The exoskeleton protects the animal from other crayfish and predators equivalent 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 blighterly 30 percent of the buckler length (Hobbs, 1987, p.31). The tail can be used to quickly dart backward if threatened. On the cephalothorax in that respect are deuce compound eyes, which are attached to assignable stalks. These stalks help the animal prote ct its eyes by retracting them if risk of exposure approaches. The crayfish also has a pointy nose and a stone of sensory antennae on its head. There are four pairs of base on balls legs attached to the thorax. asunder from walking backwards, forwards, and sideways, these legs help the animal try food in crevices mingled with rocks. Crayfish also curb a pair of strong pinchers, which are very assistive in raw and capturing food, as well as defense. They expect five pairs of swimmerets that are located under the abdomen; bailers, which are used to clog up water over the gills; and legion(predicate) specialized, food-handling legs. All of the legs on a crayfish can regenerate, or grow back if lost. Crayfish have been known to get it on in a variety of colors including green, sandy yellow, pink, etiolated or dark brown. Crayfish have a deportment 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 manlike attracts a female by touching her with his antennae and his claws. He thusly 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 fundamentally the way in which the crayfish are locked together to mate. later the sperm is in the female, the male specifys 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. Aft er a fewer weeks, hatching takes place and the small fry crayfish stay with their mommy for weeks before going out on their own. Crayfish are important to the environment and course 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 vegetation and so they transfer energy from the producer directly to higher(prenominal) trophic organisms. They are practically referred to as rubbish collectors because they vary waste into protein. Over the years, over-fishing, water pollution, irrigation demand, and disease has decreased the universe of these important animals. Man is accordingly negatively affecting the freshwater ecosystem. There are many efforts being made by conservation biologists and Fish an d Wildlife do ecosystem teams to stop the deduction ! 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 sack 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 websit e: BestEssayCheap.com

If you want to get a full essay, visit our page: cheap essay