Orange County officials launched an investigation in Laguna Niguel Regional Park after local fishermen found a large number of dead bass floating in the water.

"I saw all the dead fish," fisherman Aidan Woodward said. "There was probably like a 1,000 dead fish at least."

Woodward, who began fishing for bass at the man-made lake as a child, found the fish in the creek on Monday. He and fishermen posted pictures and videos to social media. 

"We are seeing live fish that are swimming around that are pretty much halfway dead, almost floating," fisherman Jakle Bray said. It's such a shame for having such a good fishery here for so many years and just die almost overnight."

Laguna Niguel Lake is in Supervisor Katrina Foley's district. Her staff is investigating everything from water quality to algae in the lake, as well as bubblers that add oxygen, which is crucial for the survival of the fish. 

"When the weather changes drastically, certain types of fish aren't able to take in the oxygen as quickly," Assistant Chief of Staff Alyssa Napuri said. "Bass and blue gill are not able to deal with warmer climates, and that's why the OC parks have been introducing catfish."