From the Institute of Marine Research (IMR):
A fish farm in western Norway is currently under police investigation after being identified by IMR as the source of a salmon escape. This is the first example of DNA methods being used to trace farmed escaped salmon to source of origin...Needless to say, this technology is a monumental step forward in the quest to catch all of the world's marine fugitives. I'll sleep soundly tonight.
The Directorate took samples from all fish farms in the area and delivered them to IMR in Bergen. Samples from the escapees were also collected and analysed.
Results indicated that most of the recaptured escapees originated from a specific cage, and that it was highly unlikely that the escapees came from any other fish farm.