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Piping plover abundance has most recently been affected by habitat loss. Urbanization and <br />development of beach habitats along the Atlantic Coast and Great Lakes has significantly reduced <br />nesting sites and remaining habitats are greatly fragmented. Agricultural conversion and intense <br />livestock use of wetland habitats, as well as the impoundment, containment and operation of the <br />Missouri River have greatly reduced piping plover habitat in the Northern Great Plains. Piping plovers <br />remain distributed across much of their historic range except along the Great Lakes. Recruitment rates <br />recorded from many breeding sites are not meeting those necessary to provide population growth and <br />populations appear to be declining. Exchange of birds between the three regional breeding populations <br />and movements of birds on the wintering grounds is not well understood. <br />PALLID STURGEON <br />Species Description <br />The pallid sturgeon, Scaphirhynchus albus, also known as white sturgeon, white shovelnose, white <br />hackleback (Kallemeyn 1983), and rock_ seon (Bailey and Cross 1954) is endemic to the <br />Y. ellowstone, Missouri, middle and lower Mississippi Rivers, and the lower reaches of their mayor <br />tributaries (Bailey and Cross 1954). The specimens for species identification were collected at or near <br />Grafton, Illinois on the lower Illinois and Mississippi Rivers (Forbes and Richardson 1905). The pallid <br />sturgeon grows to lengths of over 6 ft (1.8 m), can weigh in excess of 80 lbs (36 kg), and can be <br />described as having a flattened, shovel- shaped snout, a long and completely armored caudal peduncle, <br />and lacks a spiracle (Smith 1979). The mouth is toothless, protrusible, and ventrally positioned under <br />the snout, as with other sturgeon. <br />Pallid sturgeon are similar in appearance to the more common and darker shovelnose sturgeon <br />( Scaphirhynchus platyrhynchus) and have five rows of scutes that run the entire length of the body. <br />Pflieger (1975) reported the principal features distinguishing pallid sturgeon from shovelnose as the <br />paucity of dermal ossifications on the belly, 24 or more anal fin rays, and 37 or more dorsal fin rays. <br />Forbes and Richardson (1905) noted that pallid sturgeon contained 20 to 22 ribs while the shovelnose <br />sturgeon had only 10 to 11 ribs. The air bladder was also noted as being relatively smaller in the pallid <br />sturgeon. Those authors recorded differences between the pallid and shovelnose sturgeon in the <br />number of ventral radials, relative depth of lateral scutes, orbital space size, proportional lengths of inner <br />and outer barbels, mouth width, proportion of head width to head length, and proportion of head length <br />to body length. Prior to the listing of the pallid sturgeon as an endangered species, very little was <br />known about this freshwater sturgeon and much of what is currently known about the life history is from <br />recent studies conducted on the Missouri River and its largest tributary, the Yellowstone River. <br />Genetics <br />The issue of species status for the pallid sturgeon has been often debated since the pallid sturgeon was <br />Status Range Wide -PS 95 <br />1' <br />1 <br />