The surveillance program is carried out as a combination of environmental DNA (eDNA) monitoring and electrofishing. There was a general increase in eDNA concentration, going downstream, of both G. salaris and Atlantic salmon with the absolute highest concentration in the lower most station. For the locations upstream of Hellefossen in 2021, no Atlantic salmon were caught by electrofishing, while the environmental DNA analyses for Atlantic salmon were positive for two samples, indicating that Atlantic salmon is still present, however in low densities. Gyrodactylus salaris eDNA was only detected in the water sample from below Hellefossen and this corresponded well to the finding of high intensities of parasites on the Atlantic salmon parr in the same location.