Download or read book Spring and Summer Spatial Distribution of Endangered Juvenile Lost River and Shortnose Suckers in Relation to Environmental Variables in Upper Klamath Lake, Oregon written by U S Department of the Interior and published by . This book was released on 2014-03-30 with total page 62 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lost River sucker Deltistes luxatus and shortnose sucker Chasmistes brevirostris were listed as endangered in 1988 for a variety of reasons including apparent recruitment failure. Upper Klamath Lake, Oregon, and its tributaries are considered the most critical remaining habitat for these two species. Age-0 suckers are often abundant in Upper Klamath Lake throughout the summer months, but catches decline dramatically between late August and early September each year, and age-1 and older subadult suckers are rare. These rapid declines in catch rates and a lack of substantial recruitment into adult sucker populations in recent years suggests sucker populations experience high mortality between their first summer and first spawn. A lack of optimal rearing habitat may exacerbate juvenile sucker mortality or restrict juvenile growth or development.