Millions of sardines died Monday night in King Harbor due to a lack of oxygen in the water, according to the latest water tests, authorities said. And while city and county crews worked Tuesday to remove the fish, the city closed public access to part of King Harbor Marina.

Near Moonstone Park at the harbor, the surface of the water was covered by tons of sardines, in some places a foot thick, Redondo Beach police Sgt. Phil Keenan said.

The job could take several days, as dead fish on the bottom
decompose and float to the surface.

Keenan said it's believed that the sardines may have been chased into the harbor by some type of predator fish, piled up on top of one another, and perhaps couldn't get out again because of strong winds.

"We believe they died of oxygen deprivation," Keenan said, adding that the University of Southern California and other organizations just concluded tests that showed no presence of toxins or pollutants in the harbor.

"But the oxygen level was below the level sustaining life," Keenan said.

Other fish remain alive and swimming in the harbor; it's just the sardines that died off, Keenan said.

"There are millions of dead fish. Some of them are submerged, coating the bottom of the sea. Eventually, they'll decay and come to the surface," Keenan said.

Thousands of people visited the harbor to see the masses of dead sardines, but Redondo Beach police officers blocked access to the part of the marina with the highest concentration of dead fish while crews worked to remove them. Keenan said access was restricted for safety reasons while heavy equipment was being used during removal.

Redondo Beach Harbor Patrol, a division of the fire department, first reported the dead sardines at about 7:20 a.m. Tuesday, Keenan said.