A fish dieoff that’s impacting several species of fish is taking place in Clear Lake. The dieoff may have started as early as Sept. 3, according to the Clear Lake Water Quality Facebook page, run by the Big Valley Band of Pomo Indians. … At one site, at Lucerne Harbor Park, several species of fish — from threadfin shad to bass and carp — have been found washing up on the beach in large numbers. The discovery on Monday of a dead 7-foot-long white sturgeon in Buckingham — a fish whose natural range does not include Clear Lake — coincides with the dieoff, which wildlife officials are attributing to oxygen levels.