Thousands of fish have died in the Sufnersee in the canton of Graubünden following an overnight water level reduction by the Kraftwerke Hinterrhein (KHR). The Kantonspolizei Graubünden confirmed the incident on Thursday, noting that carcasses of protected species, including grayling, trout, and sculpins, were found along the shoreline. Authorities are currently investigating whether the drawdown required for electricity production caused the mass mortality.
Investigation into the cause of death
The Kantonspolizei Graubünden, in coordination with the Office for Hunting and Fisheries and the Office for Nature and Environment, is conducting an investigation to determine the exact cause of the event. Officials are specifically assessing if the abrupt withdrawal of water from the shore zones, which reportedly left juvenile fish unable to reach deeper water, played a direct role in the deaths. The Kraftwerke Hinterrhein has stated it is cooperating fully with the authorities and will support further inquiries into the matter.
The Sufnersee serves as a habitat for several protected species, including the stone loach and the sculpin, which were among the fish found dead by observers on Thursday morning.
Environmental and operational impact
Local angler Mirco Nobili reported the discovery on Thursday morning, describing a scene where fish were found leathery or struggling at the water’s edge. Nobili noted that the rapid change in water levels left little time for aquatic life to retreat to deeper areas. The incident has raised questions regarding the intersection of renewable energy production and the preservation of sensitive local ecosystems. While the KHR manages the reservoir for power generation, the presence of protected species makes the balancing of water levels a critical environmental issue.
The situation at Sufnersee highlights the inherent tension between hydroelectric power generation—often categorized as “green energy”—and the preservation of biodiversity. When reservoir levels are managed for peak energy demand, the resulting fluctuations in shorelines can have immediate, lethal consequences for species that rely on stable littoral zones. The upcoming investigation will likely focus on whether current operational protocols for water level management provide sufficient safeguards for protected fish populations.
What follows the inspection
Following the inspection of the site by the Office for Hunting and Fisheries and KHR representatives, authorities are expected to compile findings to determine if regulatory violations occurred. If the investigation confirms that the water level reduction was the primary driver of the die-off, it is possible that future operational permits or management strategies for the reservoir could be reviewed. For now, the focus remains on identifying the scope of the impact and ensuring that environmental compliance is maintained during ongoing power production activities.
Frequently Asked Questions
Which fish species were affected by the water level drop?
The Kantonspolizei Graubünden confirmed the presence of dead brown trout, rainbow trout, sculpins, stone loach, and minnows along the shore.
Who is responsible for the reservoir operations?
The Kraftwerke Hinterrhein (KHR) operates the dam and is cooperating with regional authorities during the ongoing investigation.
Are the fish species in the Sufnersee protected?
Yes, according to local reports, the reservoir is home to high-protection species, including the stone loach and the sculpin.
How should the balance between renewable energy needs and local wildlife protection be managed in the future?
