In 2013, in response to ~ 3 decades of high numbers of farmed salmon escapees entering the river, a field station with an upstream fish-trap was installed in the river Etne, Norway. This trap is monitored daily through April-November by a professional staff – permitting removal and total-sampling of all farmed escapees, and non-invasive sampling of all wild fish that are thereafter permitted to enter the river to spawn . Each year, we have also conducted extensive smolt-tagging, kelt-tagging, and juvenile sampling .
W e have now handled and sampled >20 000 adult salmon hatched in the wild, all of which have been analysed for growth and age, genotyped with 31 microsatellites for individual ID/ pedigree reconstruction, genotyped with 150SNPs that are diagnostic between the domesticated escapees spawning in the river 1986-2012 and the pre-aquaculture wild population. We have also genetic, disease and escape history of the escapees, and full-genome data for a sub-set of the adults from each year .
Here, we will present this unique system and what we have learned from this ~25% domestication-admixed wild population .