"As aquatic or semi-aquatic species move through the water DNA is shed exogenously and suspended in the aquatic habitat. The suspended DNA can be collected and detected using environmental DNA (eDNA) methods. eDNA methods use quantitative Polymerase Chain Reaction (qPCR) genetic analysis techniques to extract and detect DNA of selected target taxa from environmental samples. In this study, surface water was sampled to collect and detect Chinook salmon (Oncorhynchus tshawytscha) DNA deposited in the water column. This method relies on aquatic organisms shedding exogenous genetic material (i.e., DNA) into their environment through feces, exfoliation, mucus and urine. A positive result from qPCR analysis suggests use, by the target taxa, of aquatic features at the sample site at, or shortly preceding, the time of sample collection. The positive detection of target taxa DNA in the aquatic features used as habitat by the species can be used to establish species presence."--from Summary.
