Mass fish die-off in Greece: The search for answers begins

With extreme flooding, record temperatures, drought, wildfires and water shortages on the Aegean Islands, Greece has been fighting one extreme weather event and environmental disaster after another over the past year.
The latest one began on August 26 in and around the port city of Volos on the east coast of central Greece when over 100 tons of dead freshwater fish washed up on the shoreline after entering the Pagasetic Gulf via a small river near the port.
On August 31, Greek authorities declared a state of emergency, which will last until the end of September. A massive clean-up is currently underway.
The dead fish came from Lake Karla, which is one of the largest lakes in Greece and situated about 20 kilometers (12.4 miles) north of Volos.
The lake was completely drained in 1962 to gain more arable land and in a bid to combat malaria. It was partly restored between 2010 and 2018.
After the torrential rain and extreme flooding that came with Storm Daniel in September 2023, the lake swelled to its original size of about 180 square kilometers (69.4 square miles) within just a few days.
In the months that followed, the fish in the lake had plenty of food, and the population exploded.
Then came the hottest Greek summer in living memory. Not a drop of rain fell for months on end. As a result, the lake’s water level plummeted too quickly. Many fish suffocated.
Early reports that suggested the freshwater fish died when they entered the sea because they could not adapt to salt levels there proved to be incorrect. It was established that the fish were in fact already dead by the time they reached the coast.
While this is not the first fish die-off in the region, it is by far the largest. As a result, it has been suggested that the authorities should have been monitoring the situation in Lake Karla, noticed the die-off at an early stage and spanned nets across the Xiria River to catch the dead fish and dispose of them. But none of this happened, and the fish were washed to the coast.
Since August 26, over 100 tons of dead fish have been removed from the water in the port and on nearby beaches. Local authorities have chartered trawlers and earthmovers for the clean-up.
The dead fish are collected in containers and transported to an incinerator in the nearby city of Larissa.
But there is also a huge amount of fish that are mixed up with sand, algae and rubbish. The city of Volos is currently looking for a suitable site for a special dump to take this waste. One option would be a disused quarry in the municipality of Rigas Feraios, north of Volos. It is still unclear what the local environmental impact of storing tons of dead fish there would be.
Photos of the masses of dead fish in the water made front pages all over the world.
The stench along the waterfront was unbearable for locals and visitors alike. Many tourists left shortly after the fish appeared — a bitter blow for the local economy, which depends heavily on tourism.
For hotel-owners in the region, the situation is very difficult. For the city’s famous tsipouradika — fish restaurants serving small portions of local delicacies — it has been a complete disaster.
Although the Health Ministry says that the die-off does not pose a threat to humans, people are staying away — the stench of rotting fish would put anyone off their food.
According to the Volos Chamber of Commerce, commercial activity along the waterfront has plunged by about 80% in recent days. Representatives have said that it is an “unbelievable environmental and economic disaster.”
The government has announced that a series of support measures for businesses affected by the die-off will be launched in the coming days. 
The search for those responsible for the catastrophe is already in full swing — even before all the dead fish have been cleared away.
Volos Mayor Achilleas Beos accused the governor of the Thessaly region in central Greece, the port authority in Volos and the relevant ministries of not having done their jobs. “They didn’t do the obvious, to put a protective net,” he said.
The Supreme Court of Greece has ordered an urgent investigation, saying that it must be determined who bears criminal liability for the situation. It also pointed out that the investigation will not just focus on events of recent days but possible failings in recent months.
The authorities are also waiting for the results of analyses commissioned by the state attorney’s office to establish whether the fish died of suffocation alone or whether the reckless use of fertilizers and pesticides in the region around Lake Karla could have played a role.
If that turns out to be the case, the impact of the fish die-off on the flora and fauna in the Pagasetic Gulf would be much worse.
Until 1962, Lake Karla was the second-largest wetland in Greece. The draining of the lake took 18 months and created 80,000 hectares of arable land.
However, the impact on the region was not all good: The water table sank dramatically, pollution increased, and phytoplankton blooms occurred in the Pagasetic Gulf.
In view of these past and present environmental disasters, Professor Antonis Kokkinakis of the Faculty of Agriculture, Forestry and Natural Environment at the Aristotle University of Thessaloniki wrote on Facebook that the Greek state is not learning from its past mistakes. “Nature speaks to us, but we don’t — or do not want to — listen,” he said.
This article was originally published in German. It was adapted into English by Aingeal Flanagan.