LAUSR

The environmental DNA (eDNA) technique is a convenient and powerful tool to detect rare species. Knowledge of the degradation rate of eDNA in water is important for understanding how degradation influences the presence and/or estimate biomass of aquatic animals. We developed a new set of species-specific primers and probe to detect eDNA of Japanese eel Anguilla japonica, which is a commercially important and endangered species, and then conducted a laboratory experiment to quantify the temperature-dependent degradation of emitted eDNA. Eels were held in tanks at five different temperature levels from 10 to 30 °C and water from each tank was sampled and kept in bottles at each temperature over 6 days. The concentration of eDNA was measured every day and the results showed that temperature (T) had a significant and positive effect on the degradation rate (k) as k = 0.02T + 0.18. Improved understanding of the effect of temperature on degradation rates would help data interpretations and adjustments would increase the reliability of eDNA analysis in future studies.