Golden Algae

Golden Algae at Lake Mission Viejo

Lake Mission Viejo first experienced a serious loss of our fish population in November 2014 when the aquatic pest algae by the name of "Prymnesium parvum", never seen before in our lake, appeared. The Golden Algae released its toxin that damaged the gills of fish and compromised their ability to breathe despite good oxygen levels in our lake. Humans and other non-gill-breathers are not affected by the toxin however and affected fish is safe to eat.

Golden Algae, present in Texas and Arizona since the mid-1980s, first appeared in California in the fall of 2013 at East Lake in Yorba Linda. Several other lakes in Southern California were stricken with Golden Algae during early 2014 but LMV initially tested negative. Fish began dying in LMV on November 10, 2014 but when the water was tested again, it was found to have almost undetectable levels of the golden algae. Over the next several weeks almost all of the fish died in LMV beginning with the bass then sunfish, and finally the catfish.

LMVA has reached out to the scientific community, speaking with various researchers and governmental agencies to survey the science, history, and efforts to eradicate Golden Algae from other lakes, ponds, and rivers across the country. The difficult news is that there is no sure treatment available to get rid of this alga. LMVA’s treatments with algaecide targeting Golden Algae have resulted in only some limited and temporary benefits. The golden algae may not go away but may merely stop producing the toxin. Some reports indicate that toxic events have been more common during the colder months. Unusual fish behavior may be our best indicator of another recurring event. That behavior includes near-shore mass schooling of non-feeding fish that frequently "yawn", shake their heads and jump as well as having a blotchy skinappearance.


LMVA Board and staff are hard at work seeking a solution that will return LMV's fishery to a stable and healthy state once again.  Thank you all for your concern and support as we attempt to solve this stubborn problem.

Day Date Events
Tuesday Feb 14th 2023 LMVA Board of Directors Meeting
Saturday Feb 18th 2023 Workout at the Lake
Tuesday Mar 14th 2023 LMVA Board of Directors Meeting
Saturday Apr 8th 2023 Marine Appreciation Day
Tuesday Apr 11th 2023 LMVA Board of Directors Meeting
Sunday Apr 30th 2023 OC Triathalon

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