Allometric scaling of eDNA production in stream-dwelling brook trout (Salvelinus fontinalis) inferred from population size structure

Environmental DNA (eDNA) concentration exhibits a positive correlation with organism abundance in nature, but modelling this relationship could be substantially improved by incorporating the biology of eDNA production. A recent model (Yates et al. 2020) extended models of physiological allometric scaling to eDNA production, hypothesizing that brook trout eDNA production scales non-linearly with mass as a power-function with scaling coefficients < 1 in lakes. To validate this hypothesis, we re-analysed data from Wilcox et al. (2016) that examined the correlation between eDNA concentration and brook trout abundance in streams. We found that allometrically scaled mass (ASM) (e.g. ∑(individual mass0.36) best described patterns of eDNA concentration across streams (r2 = 0.43). ASM exhibited substantially improved model fit relative to biomass (r2 = 0.31, ∆AIC = 5.19), indicating that eDNA production did not scale linearly with biomass. However, the explanatory power of ASM was comparable ...