Ancient Hunter-Gatherers Stocked Norway's Mountain Lakes with Fish

Archaeologists have uncovered evidence that ancient hunter-gatherers introduced fish to Norway's Lake Tesse approximately 7,000 years ago. This finding, led by Axel Mjærum from the University of Oslo, represents the oldest documented instance of human-mediated fish translocation globally.

Prior to the introduction of agriculture in Norway, these early humans transported brown trout to the isolated mountain lake, situated at an elevation of roughly 850 meters. Lake Tesse, once covered by the Fennoscandian ice sheet until about 8,400 years ago, was initially devoid of life. The purpose of introducing fish was to create a reliable food source during summer foraging trips in the highlands.

Evidence from Ancient Fish Traps

The discovery of ancient wooden fish traps in 2022, when the lake's water level was lowered, provided key insights into this historical practice. Radiocarbon dating of the traps revealed that the earliest was constructed around 4950 BC. The research team also managed to precisely date some of the trap posts using the pine tree ring chronology from the central Scandinavian mountains. They found evidence that these traps were maintained for extended periods, with one post dating to between spring 2669 BC and winter 2669-2668 BC, and another from winter 2657-2656 BC.

Mjærum noted that the continued use and maintenance of these traps suggest that this fishing method was practiced from around 5000 to 2650 BC. This long-term management of the fish population highlights an early form of environmental manipulation to secure food resources, predating the agricultural revolution in the region.

Challenging Natural Dispersal Theories

While there were alternate theories about how fish came to inhabit Lake Tesse, such as natural migration or transportation by birds, the geographical features of the region, including large waterfalls, render natural upstream dispersal impossible. The presence of brown trout in Lake Tesse before modern interventions suggests human involvement was necessary.

This practice of introducing fish is not unique to Norway; similar early aquaculture activities were noted in other parts of the world. For instance, eel traps and channels constructed in Australia date back 8,600 years. However, the method by which these ancient people transported the fish to the lake remains unknown, though waterskins might have been used.

Implications for Understanding Ancient Societies

These findings offer a glimpse into the resourcefulness of ancient societies and their ability to adapt and manipulate their environment for survival. The creation of a stable and predictable food supply potentially allowed these groups to extend their stays in the mountains, supporting not just hunters but entire family groups.

The study, published in the journal Antiquity, contributes to a broader understanding of early human innovation and environmental management practices long before the widespread adoption of agriculture in Scandinavia.