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Eastern sand darter
The eastern sand darter (''Ammocrypta pellucida'') is a species of the Percidae family. The eastern sand darter is a relatively small perch, most plentiful in the Mississippi and Ohio Rivers, as well as Lakes Champlain, Erie, Huron, Michigan, and Ontario. It prefers sandy-bottomed streams and sandy shoals in the lakes.〔Daniels, R.A. Habitat of the Eastern Sand Darter, ''Ammocrypta-Pellucida''. Journal of Freshwater Ecology 8:462-479.(1993).〕 The eastern sand darter feeds on larvae of black flies and other small insects in the water. They also feed on zooplankton in small portions due to their small mouth size limiting their gape ability.〔Drake, D.A.R., M. Power, M.A. Koops, S.E. Doka, and N.E. Mandrak. Environmental Factors affecting growth of eastern sand darter (''Ammocrypta pellucida''). Canadian Journal of Zoology-Revue Canadienne de Zoologie 86:714-722.(2008).〕 Their average body size is around 1.5-2 in long and it breeds in the spring and summer in sandy-bottomed waters.〔O'Brien, Shannon M., and Douglas E. Facey. Habitat Use by the Eastern Sand Darter, ''Ammocrypta pellucida'', in Two Lake Champlain Tributaries. Canadian Field Naturalist 122:239-246.(2008).〕
==Distribution==
The eastern sand darter can be found in many areas throughout the United States and into southern Canada. In addition to the Mississippi and Ohio Rivers, it can be found in great concentration in Lake Champlain, Erie, Huron, Michigan and Ontario. They can also be found in the St. Lawrence River drainage in Canada along with the Lake Champlain drainage in Vermont south into New York, Pennsylvania, West Virginia, Kentucky, Illinois, and Indiana.〔 Currently, the greatest concentration occurs in northern Alabama and eastern Tennessee. Distribution has slowly decreased over the last few decades and two key factors could be the cause. The eastern sand darter requires clean sand substrates; hence, siltation is a major factor in their decline. Siltation decreases the quality of habitat for both egg development and adult darters by decreasing the oxygen levels within the sand in which they bury themselves. Furthermore, silted habitats can cause adult darters to not fully burrow or decrease their time burrowed which then causes them to waste energy reserves. Channel or water flow alterations, nutrient enrichment, or any other habitat modification can completely change the amount and quality of the shifting sand bars which can then turn detrimental for the eastern sand darter.〔Holm, E., and N.E. Mandrak. The status of the Eastern sand darter,''Ammocrypta Pellucida'', in Canada. Canadian Field Naturalist 110:462-469.(1996).〕 The increased construction of dams also has been a major factor contributing to the reduction of their habitats. Dams reduce river levels and flow, decrease oxygen levels in reservoir waters, and alter water temperatures, making it difficult for the eastern sand darter to reproduce at a comfortable temperature.〔Daniels, R.A. Significance in Burying in ''Ammocrypta-Pellucida.'' Copeia 79:92-94.(1989).〕 Dam construction adds a whole new dimension to decreasing the reproduction and survival rate for ''A. pellucida''.
抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』
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