Tens of thousands of fish who turned up dead along the coastal waters off Southern California over the weekend were killed by a lack of oxygen, state wildlife officials said.
The anchovies most probably took refuge in the harbor, became trapped and used up all of the oxygen in the waters at Marina del Rey, Los Angeles Times reported.
A large school of northern anchovies were spotted traveling offshore by the California Department of Fish and Wildlife staff during an aerial survey of area beaches last week, spokeswoman Janice Mackey said in an email to the Los Angeles Times.
About 300 bags of fish weighing more than six tons from the waters have been removed by a cleaning crew from the Los Angeles County Department of Beaches and Harbors, Sky News US Team reported.
Wildlife officials collected samples to analyze in a lab, Mackey said.
"We suspect these were the same ones later found in the harbor, and may have sought cover from a predator species," Mackey said. "Once in the harbor, the fish school became trapped, and subsequently depleted all of the available oxygen in the water."
Basin A of the harbor, near Bora Bora Way, saw the fish floating up dead among its docks and boats on Saturday evening.
By Sunday, stinking masses of fish carcasses blanketed the surface of the water in a small corner of the harbor, attracting hungry sea lions and pelicans, according to LA Times.
"While the sight of so many dead fish may be startling to some, this is not considered to be too unusual," Mackey said.
Similar conditions have caused other fish kills in recent years, including an incident three years ago that fouled the waters of Ventura Harbor with about 6 tons of sardines. In 2011, a die-off of millions of small fish in King Harbor in Redondo Beach was blamed on a lack of oxygen.
