Influence Of Water Collection Method On The Relationship Between Environmental DNA and Fish Biomass

The use of environmental DNA (eDNA) to detect the presence of genetic material from rare aquatic organisms is a promising new tool in fisheries science. Current methods typically aim to determine the presence or absence of a target organism. We are developing this technique utilizing quantitative PCR (qPCR), a method that enumerates copies of a target sequence, so it might be correlated, and subsequently used, to estimate fish biomass. We use the common carp (Cyprinus carpio) as a model because it is abundant, relatively well understood, and the subject of active control efforts. We investigated how eDNA collection method affected the relationship between cytochrome b copy number and common carp biomass in a laboratory setting. Precipitation and centrifugation of eDNA was compared to filtration of water through filters with four pore sizes, ranging from 0.2 to 5 μm. Centrifugation exhibited the lowest eDNA recovery, whereas all filter pore sizes tested produced a significant positive relationship between copy number and fish biomass. These results suggest that eDNA qPCR may prove to be a useful tool for routine monitoring of both invasive and game fish populations. This research is funded by Environment and Natural Resources Trust Fund.