BARCELONA (Reuters) - Archaeologists digging up a former fish market in Barcelona in northeast Spain have discovered the wreck of a ship that may have sunk about 500 years ago.

The team came across the ruined stern of a large vessel that could have sunk in the 15th or 16th centuries.

A large fragment of the boat, 10 metres long and three metres wide and crossed by more than 30 curved wooden ribs, was found in good condition at a depth of five metres below sea level.

"It is of great importance because it is unusual to find underwater archaeological remains and when we do the studies on the keel and wood, etcetera, more details will be known," said Santiago Palacios Nieto, 30, director of the archaeological team, told Reuters.

"What we've found is a fragment of a ship, likely of Mediterranean-style construction, but with Atlantic influences —probably from the Basque Country or Galicia."

The timbers of the vessel had been preserved by the damp sand that covered it. The team must now ensure the wreck is preserved from drying out, so it has to be watered night and day.

(Reporting by Graham Keeley, Alejandra Angulo Alonso, Nacho Doce; Editing by Alex Richardson)