The species-level eDNA monitoring i

The species-level eDNA monitoring is often used to detect commonspecies, rare and endangered species, and invasive species. The eDNAof many species in various habitats was successfully detected by qPCR(Takahara et al., 2013; Sigsgaard et al., 2015) , a n d t h i s i s t h e m o s tpopular species-level eDNA detection method (Fig. 5). Jerde et al.(2011) used eDNA to monitor bighead (H. nobilis) and silver carp(H. molitrix). In that study, eDNA surveillance was used to delineatethe invasion front of these two invasivefishes in the Chicago area water-ways linking the Mississippi River and Great Lakes basins. In addition,the successful detection of Asian carp in the Great Lakes basin by theeDNA method could be employed for basin-wide surveillance of incipi-ent or remnant populations (Jerde et al., 2013).Research has shown that the relative abundance of mt- and nu-eDNA can be indicative of recent reproductive activity of Macquarieperch in the field, and fish eDNA methodology for detecting reproduc-tive activity has the potential to increase our knowledge of the repro-ductive biology of elusive species (Bylemans, 2018). Bracken et al.(2019) utilized a species-specific qPCR assay to monitor spatial andtemporal patterns of Petromyzon marinus via eDNA concentrationwithin two river catchments; they found that eDNA concentration increased at the onset of observed spawning activity and that patternsof concentration increased from downstream to upstream over time,suggesting dispersal into the higher reaches as the spawning seasonprogressed.