Thousands of fish dying off in Lake Elsinore amid Airport Fire; biologists monitoring water

LAKE ELSINORE (KABC) -- Biologists are monitoring the water at Lake Elsinore to see if falling ash from the Airport Fire could possibly be contributing to fish dying off at the lake.

Thousands of threadfin shad have been found dead in the past couple of days. Community Support Manager for the City of Lake Elsinore Adam Gufarotti said the issue was first reported to the city Wednesday night.

"We're still gathering data, it's still very early," he said.

Gufarotti told ABC7 there are a number of things that cause fish die-offs.

"The threadfin shad is a very small fish and it's very vulnerable to changes in pH and temperatures and dissolved oxygen," he said. "So when the lake heats up, this fish has problems. When water heats up as what we've seen in the last couple of weeks, we've had a heatwave, and the lake heats up, this fish species has problems."

Gufarotti said when the lake heats up, its carrying capacity of oxygen decreases, so there's less dissolved oxygen at the bottom of the lake.

That's when the threadfin shad essentially go into crisis.

"That's what we're seeing today," said Gufarotti.

In February, the city installed a nanobubble generator that basically injects the lake with oxygen. The city also added five monitoring stations.

Gufarotti said biologists are collecting data from those stations to get a better idea of why the fish are dying.

Meanwhile, Lake Elsinore reopened Friday after it was closed to the public due to firefighting operations.

So far, the Airport Fire has burned 23,494 acres in Orange and Riverside counties.