The sand roller, Percopsis transmontana, is endemic and considered rare in the lower Columbia River drainage, including the Willamette River and its tributaries. Historical records in the Willamette Basin are scarce. In 2005, we surveyed historical and some recently documented locations to determine the current distribution of sand rollers in the Willamette River basin. Sand rollers were found at 41% of the locations sampled, including most Willamette River subbasins. Sand rollers preferred slow-water habitats in low gradient streams and were most frequently associated with roots, other large wood, and undercut banks over sand or gravel substrates. Sand rollers were more common at locations containing only native fishes; larger numbers were collected at locations where nonnative fish were absent. Infrequent reporting of this species is probably related to its secretive daytime behavior and to inefficient gear, rather than to actual rarity.
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