Genetic tests conducted on fish bones found in a shipwrecked vessel off the coast of Israel, south of Haifa, indicate that a now-extinct subspecies of tilapia existed as early as 1,300 years ago in the country.

The seventh-century ship (from the early Islamic period) was found in the Mediterranean Sea about 100 meters away from Dor Beach, at the foot of the Carmel Mountains.

The species of tilapia that still exists in Israel, and popularly called St. Peter's fish (musht, in Hebrew), typically lives in fresh water.

The underwater excavation team that studied the wreck was headed by Prof. Yaacov Kahanov, a University of Haifa marine archaeologist. Among the findings were urns containing thousands of bones of small fish.

The bones were sent to the genetics laboratory of Prof. Micha Ron of the Volcani Center, a government-sponsored agricultural research organization located outside Tel Aviv.

“We sequenced a section of DNA and compared the findings to all the fish that exist today. We found great similarity to tilapia – with the exception of one mutation,” says Ron. The mutation appeared again and again in all the bones that were examined, which means that the bones probably belong to a subspecies that can no longer be found in nature.

Open gallery view Bones found inside urns at the underwater archaeological site in the Mediterranean. Tilapia are usually found locally in fresh water. Credit: Y. Gottlieb

Besides fresh water sources, the ancient species tilapia apparently lived in the estuaries of rivers flowing to the Mediterranean. It is also possible that at some point, the fish was bred inside special installations, perhaps a type of ancient fish farms. Structures of this type have been discovered at excavations at the Jisr al-Zarqa and Caesarea beaches, which are not far from Dor.

Kahanov emphasizes that the urns in which the fish bones were found were in the bottom part of the ship.

“It’s possible that the sailors wanted to keep them at a low temperature,” he says. “These are very small fish and they may have been used to prepare a fish stock, a kind of sauce we are familiar with from the Roman period. They may have wanted to trade in them or to use them aboard the ship.”