- Hunter-gatherers transported brown trout into Norwegian mountain lakes at least 7000 years ago, representing the oldest known human-mediated fish translocation.
- Lake Tesse, located at 850 meters elevation, was covered by ice until about 8400 years ago and later became a rich trout fishery, yielding 9 tonnes annually before hydroelectric development.
- Alternative explanations like bird transport or natural upstream migration are ruled out by geography, such as impassable waterfalls.
- Wooden fish traps discovered in 2022 at Lake Tesse were radiocarbon dated to around 4950 BC, with some posts precisely dated to 2669-2668 BC, indicating sustained trap use from 5000 to 2650 BC.
- This early fish management predates farming in Scandinavia and may have involved transporting fish in waterskins, supporting summer highland foraging by family groups.