Energy Density of Three Prosopium Fish Species Endemic to Bear Lake, Utah-Idaho

We used bomb calorimetry to quantify the energy density of three fish species endemic to Bear Lake, Utah-Idaho that were collected in 2020 – 2021. We collected Bear Lake Whitefish Prosopium abyssicola , Bonneville Whitefish P. spilonotus , and Bonneville Cisco P. gemmifer . We found that mean (± standard deviation) wet weight energy densities were 6,312 (± 760) joules per gram for Bear Lake Whitefish, 5,301 (± 778) joules per gram for Bonneville Whitefish, and 4,743 (± 443) joules per gram for Bonneville Cisco. We built linear mixed models and found relationships between energy density and dry matter ratio (i.e., ratio of dried weight to wet weight of a fish) for all three species, suggesting that the energy density of future samples collected in Bear Lake could potentially be determined from comparisons between the dried and wet weight of fishes belonging to these species. Our results will be useful for future bioenergetics modeling with these three Bear Lake endemic species, and potentially with others species in related genera that share similar feeding, behavior, and life history traits.