Thesis (M.S., Environmental Science)--University of Idaho, June 2014 | Studies were conducted in 2011 and 2012 on paddlefish stocks from North Dakota, Montana , and Oklahoma to develop a better understanding of paddlefish physiological based on energy content. Lipid accumulation and storage in juvenile paddlefish in relation to age, stock, tissue type, year, and an index of growth using RNA/DNA ratios were pursued in Chapter 2. An emphasis on growth and a relatively large rostrum size in age-0 and age-1 fish may be adaptive in avoiding predation while accruing necessary energy reserves for overwintering. Chapter 3 provides reference data for proximate composition of 3 tissue types from wild adult paddlefish, and investigates lipid accumulation and storage in adult paddlefish in relation to tissue type within individual fish, between sexes, and between two different stocks. Life history, growing season, and metabolism may help explain observed differences in lipid concentrations. Chapter 4 concerns suitability of alternate methods of estimating energy density in juvenile and adult paddlefish.