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The northern hogsucker (''Hypentelium nigricans'') belongs to the family Catostomidae, the suckers. It is native to the United States and Canada. It prefers clear, fast streams, where it can forage through pebbles for bottom life, especially aquatic insects. It grows up to 2 feet (60 cm) in length. It lives in the rivers of the Mississippi River Basin, its range extending from Oklahoma and Alabama northward to Minnesota. It is present in the Great Lakes and rivers of the mid-Atlantic region. Its current range is similar to its historical distribution, except in western areas, where it has experienced some extirpations. Habitat disturbance due to agriculture practices in states such as South Dakota, Iowa, Missouri, Kansas, and Oklahoma have contributed to the extirpation events.〔Raney, E. C., and E. A. Lachner. 1946. Age, growth, and habits of the hog sucker, Hypentelium nigricans (LeSueur), in New York. American Midland Naturalist 36(1):76-86.〕 Males can reach sexual maturity in their second season, while females usually do not reach maturity until their third year. Specimens in smaller streams are smaller and take longer to mature. ''H. nigricans'' may reach up to 33 cm by the end of its fifth growing season. Exceptionally large specimens of this species are usually female. The maximum life span is about eleven years.〔 Although the species is not currently found on any state or federal threatened and endangered listings, it is still susceptible to the manmade influences that have affected other freshwater fish species. Channelization, sedimentation, pollution, and dam construction always have the potential to alter populations of the species. Lack of suitable spawning habitat could be a detriment in the future and should be monitored closely.〔Grabowski, T. B., N. L. Ratterman, and J. J. Isely. 2008. Demographics of the spawning aggregations of four Catostomid species in the Savannah River, South Carolina and Georgia, USA. Ecology of Freshwater Fish 17(2):318-327.〕 Sedimentation degrades living and breeding habitat within the streams.〔Matheney, M. P. and C. F. Rabeni. 1995. Patterns of movement and habitat use by northern hogsuckers in an Ozark stream. American Fisheries Society. transactions 124(6):886-897.〕 ''H. nigricans'' can be found in national and state parks throughout its range, the largest being the Great Smoky Mountains National Park. It is common throughout all streams in the park up to 2800 feet in elevation. It is protected in park habitat.〔Grossman, G. D., and R. E. Ratajczak. 1998. Long-term patterns of microhabitat use by fish in a southern Appalachian stream from 1983 to 1992: effects of hydrological period, season and fish length. Ecology of Freshwater Fish 7(3):108-131.〕 The fish can be found in or next to riffle areas in warm water, medium sized creeks and small rivers. It can also occur in cold water streams, tiny creeks and large rivers and on occasion in reservoirs. Its diet mainly consists of insect larvae, crustaceans, mollusks, diatoms, and bits of vegetation. While feeding, it scrapes of the top surface of rubble, turns over stones on the bottom, and sucks the loosened material which contains a variety of small organisms. As it feeds, other fish, such as shiners and smallmouth bass position themselves downstream to feed on the free-flowing materials the hogsucker roots up. Predators of the northern hogsucker typically vary depending on the environment. During its early years in shallow, fast-moving streams it can fall prey to piscivorous species. Later in life it is typically one of the larger species in the waterways. In the northern tier of its range it lives in deeper streams and lakes and are sought by large predatory fish such as muskellunge and northern pike. Sometimes it competes with other sucker species and redhorse for breeding habitat. During the egg-laying process, daces, minnows, and chubs will sometimes forage on the freshly expelled eggs.〔Scott, W. B., and E. J. Crossman. 1973. Freshwater fishes of Canada. Fish. Res. Bd. Can. Bulletin 184:1-966.〕 Spawning takes place in shallow water riffles usually during May, when the water temperature is about 15°C. Breeding males will congregate over these gravel areas where each receptive female may be courted by several males. The spawning activity is violent, and shallow depressions are formed in the gravel from the commotion. The eggs are non-adhesive and settle on the gravel. The hogsucker is not a threatened species. It is sympatric with threatened species, however, and efforts to conserve these have benefitted the hogsucker.〔 ==References== 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Northern hogsucker」の詳細全文を読む スポンサード リンク
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