Aquatic Midge Flies around the Lake: July Update

​If you’ve noticed flying insects around the Lake, you have also seen the reflection of an imbalanced Lake ecosystem. The creatures hovering near the Lakeshore are harmless aquatic midge flies. They may look a little like mosquitoes, but don’t worry! Midge flies do not bite, do not feed on blood, or carry diseases like true mosquitoes. They are an unfortunate nuisance, but also reflect the importance of a healthy Lake. ​ Aquatic midge flies (from the family Chironomidae) are a natural component of lake ecosystems worldwide. The life cycle of a midge fly spans between 3 and 7 days, from larva to adult. Swarms tend to occur throughout the summer, when the warm weather spurs reproduction. In a balanced ecosystem, midge flies play a valuable part in the larger food chain: several varieties of fish eat the underwater larvae casings, and other insects eat the flying adults. ​ However, as a result of the Lago Santa Margarita’s golden algae bloom and subsequent fish kills, the Lake no longer had the organic resources that would normally keep the midge population at bay. SAMLARC briefly considered insecticide treatments, but decided against harsh chemical sprays: fumigation only deters the population by 24 hours, and lingering fumes could pose a threat to the ecosystem and community at large. ​ At the July 24th, 2018 Board of Directors Meeting, the Board unanimously approved the introduction of fathead minnows into the Lake. The fathead minnow (Pimephales promelas) is a natural predator of midge flies, feeding on the midge flies’ underwater larvae. This is an important facet of midge fly population control: though chemical sprays provide temporary relief from adult swarms, underwater treatment is expensive and ineffectual. Fathead minnows offer a natural method of battling the larvae population, reducing the number of flies that reach adulthood. As water samples taken in July 2018 have shown sufficient decrease in golden algae levels (the primary instigator of fish kills), it has been determined that these hardy fish can be introduced to the Lake to mitigate the midge fly population without great strain on the Lake’s ecosystem. ​ The fathead minnows were purchased on Friday, July 27th and are expected to arrive at the Lake on Tuesday, July 31st. We hope to see a reduction in the aquatic midge fly population within a few weeks, and we are continuing to research additional, environmentally-sensitive methods of midge fly population management. ​ Thank you for your patience as we research and implement the most impactful and sustainable methods of Lake ecosystem stewardship. Updates on the Lake Ecosystem Repair Project will be published as they become available. ​ For questions regarding the Lake, please contact Jerry Corpuz, Beach Club & Aquatic Facilities Manager. He can be reached at 949-709-4009, or For more information on the Lake Ecosystem Repair Project, please contact Jeremy Pipp, SAMLARC Assistant General Manager. He can be reache