At least 3,000 dead fish were found floating in the Malibu Lagoon last Thursday morning, following a mass die-off that was still being investigated by California State Parks scientists as of Tuesday, Aug. 28.
California State Parks Angeles District Superintendent Craig Sap said Thursday the cause of the mass die-off was still under investigation and could take several days to confirm. The working theory was that high water temperatures caused hundreds of fish to die, either Wednesday or early Thursday morning.
“It was 28 degrees Celsius,” Sap said in a phone call with The Malibu Times Thursday afternoon. That means the water temperature in the lagoon was measured at a little over 82 degrees Fahrenheit. “It may be related,” Sap said.
According to a story published this week in the LA Times, water temperatures measured this summer in Southern California have shown increases, including at the Santa Monica Pier (measured at 72 degrees, over the usual 68)—although temperatures at Zuma Beach were measured at 77 degrees, just one degree above normal.
By Tuesday, water temperature remained the main theory, although scientists were also considering the idea oxygen levels in the lagoon may have dropped overnight and come back up to normal by morning.
Though fish die-offs have occurred in and around Malibu in the past, Sap said this was the largest he could recall seeing in his years working for the state.
“I’ve seen—not to this degree—but historically, I’ve seen this happen before. I can’t recall how long ago, but I’ve seen some die-offs,” Sap said.
Longtime local Pete Haynes said he has witnessed die-offs in the Malibu Lagoon and Malibu Creek over the more than 60 years he has called Malibu home, including a major die-off of steelhead in 2012.
According to a story published in the Topanga Messenger in 2012, a “wholesale die-off of steelhead trout” occurred in Malibu Creek that year—but Haynes said he and City Council Member Jefferson “Zuma Jay” Wagner (pier concessionaire and longtime surfer) did not spot any dead steelhead when they went to the lagoon following the die-off.
Haynes added that the die-off did not appear to affect fish farther up in the creek, just those in the lagoon.
Most of the fish found floating belly-up in the lagoon were mullets, with some other, carp-type fish, Sap said.
“So far, the steelhead seem to be weathering through it, which is great,” Sap said in a follow-up phone interview on Tuesday. Southern California Steelhead Trout, a subspecies of steelhead found in waterways between Santa Maria and San Diego, have been considered endangered since 1997.
The Malibu Lagoon underwent a controversial restoration project in 2012 and 2013. Since then, scientists have touted successful reintroduction of local plant and animal species, but locals have raised concerns over alleged failures in the project. One common complaint is the lack of breeches in the lagoon, meaning lagoon water is not mixing with ocean water.
Information published by the City of Malibu on its website Monday said die-offs were common before the restoration, and that the lagoon project had successfully increased oxygen levels.
“Prior to the Malibu Lagoon restoration in 2012-13, smaller fish die-offs occasionally occurred within Malibu Lagoon and are not unusual for estuaries, lakes, marinas, and similar areas,” the information stated. “The circulation and dissolved oxygen levels of the lagoon post-restoration have significantly improved compared to pre-project conditions, and provide higher quality fish and wildlife habitat.”
Removal of the dead fish from the lagoon began Monday, and by Tuesday a contractor had been hired to more efficiently remove the thousands of fish—which had begun to smell badly, with the scent detectable from nearby Malibu shopping centers and in the Serra Retreat neighborhood. Sap said the contractor would begin work early Wednesday.
“We’ve gone to landfills a few times already with bags of what’s been removed, but it’s just to get rid of as much as we can as fast as we can, to get rid of the odor,” he said.
