Thousands of dead fry washed up in Puerto Pollensa

A local resident, Iván Simón, reckons that they were red prawns. He saw some on Wednesday, but by Thursday they had spread as far as the military base.

He has contacted the Balearic government's fisheries ministry, explaining that, from his experience, prawns usually die because of high levels of nitrites (faecal) or high temperatures. They were no more than three millimetres long.

Local fishermen said that the larvae or fry they saw were shorter than this - less than a millimetre. It was difficult to ascertain what they were, but if they were prawns, they were of a variety with no commercial use because they cause stomach problems. Fishermen in Puerto Pollensa don't normally catch prawns.

A few days ago, there were loads of jellyfish on the same beach. Currents could be causing this, the fishermen added, though high temperature is also a possibility.