Archaeological research at high-altitude Lake Tesse in Norway’s Jotunheimen region suggests that 7,000 years ago Stone Age communities were introducing fish into mountain lakes by artificial means, developing an early form of fish farming. The project, led by archaeologist Axel Johan Mjærum of the Museum of Cultural History in Oslo, provides some of the earliest and most concrete evidence that hunter-gatherer groups were not just passively exploiting nature but deliberately engineering and managing their environments.
Secrets revealed as water levels fell
The discovery began in 2022 when amateur archaeologist Reidar Marstein, hiking by Lake Tesse, noticed a series of regularly spaced wooden stakes on the exposed lakebed as the water level dropped. The following summer, archaeologists excavating the area recovered 113 wooden stakes, which were then subjected to dendrochronological (tree-ring) analysis. The results showed that the earliest of these fish traps dates to around 5000 BC, roughly 7,000 years ago, and that the system remained in use for at least 2,300 years.
Life carried up the mountains in leather bags
According to the researchers, it would have been impossible for trout to reach this lake on their own by jumping the steep waterfalls that separate it from lower waters. Lake Tesse lies about 850 metres above sea level. Stone Age people are thought to have caught live fish in rivers downstream and transported them step by step uphill, probably in waterproof containers made from animal hides. The team considers it likely that this laborious process, and the time needed for the fish to establish a self-sustaining population in the new waters, took decades and perhaps even a century. This indicates a collective investment by the community, not just to meet immediate needs but to secure food resources for future generations.
Other archaeological evidence worldwide supports the idea that prehistoric communities actively managed water sources and aquatic life. For example, research in Egypt suggests that around 3,500 years ago people were already gathering fish from lagoons in the Sinai Peninsula and engaging in early fish-farming practices [1]. Similarly, at high-altitude Lake Redon in the Pyrenees in Spain, studies indicate that humans introduced fish artificially at a very early date [2]. On the Brittany coast of France, a 7,000-year-old monumental stone structure discovered underwater has also revealed that early communities developed complex engineering solutions to control water resources and trap fish [3].
A collective investment in the future
At Lake Tesse, the complex fish trap system provided vital food security for groups engaged in prestigious reindeer hunting in the surrounding mountains. Even if the hunt failed, the fish in the lake allowed people to stay in the highlands for longer periods, and in some cases may have supported permanent or semi-permanent settlement in this harsh landscape. The discovery suggests that fish populations in mountain lakes we often regard as entirely natural may in fact be the legacy of deliberate, large-scale environmental engineering carried out by people who lived thousands of years ago.
Sources and further reading
- [1] NLA University College in Bergen - Academic Positions
- [2] NLA University College in Bergen - Academic Positions
- [3] Egyptians farmed fish 3,500 years ago: study
Image & News Source: Sciencenorway / sciencenorway.no