Hundreds of fish die in lagoon in tony Malibu, California

California officials are trying to solve a stinky mystery: A die-off has left hundreds of fish floating in a recently restored lagoon on the tony Malibu coast.

California State Parks Angeles District Superintendent Craig Sap said Monday that scientists believe the Malibu Lagoon die-off, which began last Wednesday, is likely caused by the unusually warm water temperatures.

But other possibilities include elevated nutrient levels, dropping levels of dissolved oxygen or having too many fish in the lagoon. Officials are taking water samples and fish for testing.

Malibu Lagoon underwent a controversial restoration project in 2013.

Sap says officials improved the ecosystem by providing better oxygen levels and that the number of fish in the lagoon has since increased.