Report: Menifee Lake Fish Kill Attributed to Toxic Algae

The south end of Menifee Lake was clear of dead fish Friday afternoon -- a week after thousands ...

The south end of Menifee Lake was clear of dead fish Friday afternoon -- a week after thousands of fish died there.
Additional tests of the water in Lake Menifee showed high levels of toxic algae that is considered to be the cause of the death of thousands of fish since the end of April, the lake manager said today.

Ken Durante has prepared a two-page report of the test findings that is available to Menifee Lakes residents in the lake office and will be included in the next newsletter of the homeowners association in that private community. It describes the presence of Prymnesium Parvum – commonly referred to as golden alga – in the lake.

Menifee 24/7 has viewed the report from Aquatic Consulting & Testing, Inc., the Arizona lab to which water samples were sent last week when several species of fish continued floating dead to the surface (below). According to the report, “golden alga was detected and dominant in the samples tested.”

According to the Arizona Department of Game and Fish, golden alga is rarely found in California lakes but has been responsible for many fish kills in Arizona and Texas lakes. This alga is a tiny, one-celled aquatic organism propelled by two “tails”, called flagella, that help it move through the water.

As described in Durante’s report, golden alga release toxins that affect gill-breathing aquatic organisms. In a bloom situation – which is consistent with current climate and weather conditions – enough toxins are released into the water to kill fish in great numbers.

According to the report, the toxins cause fish gills to lose their ability to exchange water and absorb oxygen. Fish then die of asphyxiation. An algae bloom was traced to April 26 – the day before fish began dying.

Tests of the water showed more than sufficient levels of oxygen in the water, which seemed to disprove a rumor that a newly installed aeration system is faulty. The oxygen level was measured at 10.8 parts per million. Anything above 4.0 ppm is considered safe, acco