Porto, July 4, 2025 (Lusa) - Salting tanks used during the Roman Empire in Galicia reveal a diet based on sardines, a team led by researchers from the University of Porto’s marine research centre has concluded after extracting and sequencing ancient DNA.

The study, published in the international scientific journal Antiquity on Wednesday, “shows that salting tanks used to ferment fish into pastes and sauces popular throughout the Roman Empire predominantly used European sardines as their main ingredient,” the Interdisciplinary Centre for Marine and Environmental Research (CIIMAR) said in a press release.

In research carried out at the archaeological site of the Roman village of Adro Vello, in O Grove, Pontevedra, Galicia, Spain, scientists were able, “for the first time, to extract and sequence ancient DNA,” showing that the method is “effective in identifying animal remains that have been damaged over time.”

“In this study, we have demonstrated that usable DNA can survive in fermented environments, such as the brines used by the Romans,” concludes researcher Paula Campos.

On the other hand, “by comparing the DNA sequences of the archaeological remains with current species, researchers discovered that the vats at the Adro Vello salting factory salted sardines in Roman times, and that these are closely related to those currently found in the same area”.

This confirms “genetic continuity despite the high mobility of the species”.

According to the scientist, “the methods allow the identification of species from these processed bones even under conditions that promote DNA degradation”.

The new methodology “will enable the study of archaeological remains in other salting vats from other regions, making it possible to find out what other species were used”.

“Furthermore, it has significant implications for other types of archaeological studies of fish in the future, allowing us to understand not only the evolution of these species, but also the history of their connection to humans,” adds CIIMAR.

In addition to CIIMAR researchers, researchers from the University of Vigo and the University of León in Spain, and the University of Copenhagen in Denmark, participated in this study.

The research was funded by national funds from the Foundation for Science and Technology and European Regional Development Funds under the PT2020 Programme.

ACG/ADB // ADB.

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