MADRID, Spain — Millions of anchovies -- a protected species in Europe -- have died in northern Spain after an unexplained mass beaching, officials said Friday.

The fish, all juveniles, were found stranded along large stretches of Colunga beach, 35 miles east of the port city of Gijon, a normally pristine seaside landscape in the verdant province of Asturias.

"More than three tons have been found so far, and our main -- untested -- hypothesis at the moment is that they tried to flee from predators and accidentally beached," said Luis Laria, chief coordinator of a marine protection unit working with the government.

Laria said a European Union moratorium on fishing anchovies along the northern Atlantic coast of Spain and the western coast of France has been in place for two months. Less rigorous fishing restrictions had been used for the previous two years.

These anchovies are considered susceptible to extinction and are therefore closely monitored by scientists, according to Spain's Environment Ministry.

Although anchovies are exported from elsewhere in the world, including Peru and Chile, Laria said anchovies from the Atlantic off Spain and France are the most valued and expensive because of their flavor, derived from their nutrient-rich environment.

If the beached specimens had grown to full maturity, they would have represented more than 100 tons of potential breeders.

"It's a bit of a disaster," said Laria. "We can't fish them because they're so rare, and now they've killed themselves."

Laria said that experts had studied the dead anchovies and found no evidence of toxic chemicals that could have caused the beaching. "The likelihood is that a shoal tried to swim away from hungry dolphins or tuna."

A factor that may have disoriented the fish is unusually high water temperatures off Colunga in the high 70s, Laria said, adding that such a mass beaching of anchovies is unprecedented in northern Spain.

A cleanup team was dispatched Friday to begin scooping up the dead fish to avoid further unwanted environmental side-effects.