1,500 dead fish were found at a private duck club called Wheeler Island, in a pond adjacent to Honker Bay.

"And of those 1,500 fish it appeared that the majority were striped bass and the others were carp."

Mark Lucero is a patrol captain with the state Department of Fish and Game. He says the pond was drained by a contractor working for Chevron to repair a petroleum pipeline.

In a statement, Chevron says it had the proper work permits for the project. Lucero says investigators are checking into that.

"At this point we understand that the permit was for a dry work site. And obviously we had a wet worksite with the siphoning of the pond. So we're trying to ascertain what happened."  

Chevron officials say they are cooperating with authorities.