Prehistoric Danes continued to fish for food even after the rise of agriculture

(CN) — Prehistoric people in what is now Denmark continued to rely on fish for sustenance even after the introduction of domesticated livestock, researchers say in a study released Wednesday in the journal PLOS One, challenging the notion that the rise of agriculture among early humans resulted in an abrupt change in subsistence strategies.

Danish and German researchers analyzed animal remains from the coast of the prehistoric Syltholm Fjord on the Danish island of Lolland, with samples ranging from the late Mesolithic period to the Bronze Age (roughly 4500 - 800 BCE). This time period includes the rise of agriculture in the region at around 4000 BCE.

The introduction of agriculture “is assumed to have been an event of major scale that transformed societies suddenly and at large,” the researchers say in the study. But they found the remains of fish appeared consistently throughout the time periods analyzed.

Many of those fish remains appeared alongside stationary fishing structures and other signs of human activity, like butchered animal bones and stone and ceramic artifacts, indicating they came from human food waste as opposed to naturally occurring deposits of deceased fish.

This suggests fish continued to play a substantial role in the diet of prehistoric humans at the Syltholm Fjord for several millennia after agriculture was introduced to the area.

Prior papers have attributed the continuation of fishing activity at the Syltholm Fjord after the introduction of agriculture to early humans near the fjord being a “relic population” that continued a hunter-gatherer lifestyle while their neighbors adopted agriculture. The study’s findings dispute this notion, with the researchers finding remains of fish from the same time periods as those of domesticated animals like cattle, indicating humans near the Syltholm Fjord were both fishing and raising livestock.

“The introduction of livestock is often considered a major change in subsistence strategies, yet we do not see any significant changes in other areas of food production — fish just continued to be a relevant food source,” lead author Daniel Groß, with the Museum Lolland-Falster, said in a statement.

The researchers found prehistoric humans near the fjord continued to target the same species of fish across thousands of years without clear evidence of an impact on the ecological makeup of fish populations, such as species depletion or a reduction in fish sizes, suggesting “a well-developed and potentially sustainable fishery practice.”

From the late Mesolithic era to the mid-Neolithic period, humans at the Syltholm Fjord relied on large wooden structures known as fish weirs to fish in the fjord. This method of fishing required communal cooperation, which the researchers speculate may have guarded against overexploitation of fish populations by encouraging mutual restraint.

“Even though people were fishing in the fjord for millennia, their impact on the environment was not clearly traceable," Groß said. “This research indicates that Neolithic fishing was sustainable, to a degree.”