Arizona lake closed due to potential safety hazards after fish kill event

Access to San Carlos Lake has been restricted after a catastrophic fish kill left decomposing fish around one of Arizona’s largest lakes, authorities announced Friday.

The San Carlos Recreation and Wildlife Department said the fish died due to a combination of recent drought conditions and water released from the nearby Coolidge Dam.

Officials said the dead and decomposing fish created a public health concern. Visitors are being asked to avoid the affected area while conditions are monitored.

Due to health risks, the San Carlos Recreation and Wildlife Department said visitors are not allowed to fish, harvest or take fish from the lake. They also can’t take part in any fishing-related recreational activities.

What caused the fish kill at San Carlos Lake?

San Carlos Lake is a popular destination about 2.5 hours from both Phoenix and Tucson. It features 158 miles of shoreline and has produced some of Arizona’s largest recorded fish, including a nearly 72-pound flathead catfish.

The reservoir primarily serves as an agricultural water source for the San Carlos Irrigation Project, meaning water levels can fluctuate significantly.

Recent drought and a lack of winter snowpack caused the lake to drop to its lowest level in years, according to PinalCentral, which reported that the lake was at 386 acre-feet as of Wednesday.

When water levels fall too low, algae can bloom and consume the remaining oxygen in the water. Without enough oxygen, fish cannot survive, leading to widespread deaths.

The last time a massive fish kill took place at San Carlos Lake was in 2018.

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