Like many local businesses, Wloch has seen bookings plunge by 90% following the as yet unexplained catastrophe on the lush banks of a river between Poland and Germany.

“I’m just starting to realise the scale of what happened,” Wloch told AFP.

“Yesterday, I slept all day because I was depressed, unable to move,” he said.

In the empty tourist marina of Cigacice in Poland, firefighters in a rubber dinghy are still removing dead fish while environmental agency workers take water samples for tests.