ATHENS – Freezing winter weather in Greece that even iced over some parts of the sea also caused hundreds of thousands of farmed fish to freeze in their waters afer a heavy snowstorm.

The dead fish, seabream and white seabream, began to emerge on the surface of the Richo Lagoon of Drepano Lake on Jan. 25 as the temperatures in the water dropped to as low as zero degrees Celsius, the freezing point.

“The destruction is huge, it is estimated there are around 50 tonnes of dead fish,” Ioannis Ouzounoglou, who works at the state-owned fish farm, told Reuters after collecting some in his rowing boat.

“In all the last years that I have been recording and measuring temperatures in the area, I never expected that we would have such low temperatures in the minuses,” he said.

Locked into the lagoon, the fish couldn’t get out to deeper waters of the lake or to the sea to survive, scientist Konstantinos Perdikaris from the Department of Fisheries told the news agency. “They died from thermal shock,” he said.

Seabream, unlike other fish, are susceptible to low temperatures and cannot survive below 4C (39 degrees Fahrenheit), Perdikaris said. The fish were at a shallow depth where the cold was quicker to penetrate the water.

“At shallow depths the reaction of the air is more intense,” he said. Usual temperatures in the lagoon this time of year are about 7-8 Celsius (44.6-46.4 Fahrenheit,) well above freezing.

Drone video showed thousands of dead fish floating on the surface of the lagoon and on the shores. “Every year we free them into the lake, but this year unfortunately we did not have the chance to free them in time, because the frost (came quickly),” said Ouzounoglou.