THE MOSQUITO LIFE CYCLE Our services MOSQUITOFISH FACTS ABOUT Mosquitoes have four distinct The Marin/Sonoma Mosquito MOSQUITOES developmental stages: egg, larva, pupa and adult. The average time it takes a & Vector Control District is mosquito to develop from egg to adult committed to protecting the is five to seven days. Mosquitoes require 1. All mosquitoes need water to complete their life cycle. Prevent health and welfare of the water to complete their mosquitoes from breeding by eliminating communities in which we serve. life cycle. or managing standing water. Our programs and services are EGG RAFT supported by property taxes and Most mosquitoes lay egg rafts 2. There are over 20 that float on the water. Each are provided free of charge to all different types of raft contains approximately residents in Marin and Sonoma mosquitoes in Marin and 100 to 400 eggs. Within a counties. Sonoma counties. few days the eggs hatch into larvae. Our services include: LARVA 3. Only the female The larva or “wiggler” comes • Mosquito Control & Mosquitofish mosquito bites to obtain to the surface to breathe a blood meal. The male through a siphon tube. It • Ground-Nesting Yellowjacket Control mosquito feeds only on feeds on micro-organisms and plant juices. organic matter in the water. In • Rodent Control Advice a matter of days the larva will molt (shed its skin) four times. On the fourth molt it will change into a pupa. 4. The female mosquito may live as long as PUPA three weeks during the The pupa or “tumbler” cannot summer or many months eat. It breathes through two over the winter in order tubes on its back. The adult mosquito grows inside the to lay her eggs the pupal casing and within a few following spring. days, when fully developed, it will split the casing and emerge as an adult mosquito. Marin/Sonoma Mosquito & Vector Control District ADULT 595 Helman Lane, Cotati, CA 94931 The newly emerged adult rests Monday through Friday 7:00am to 3:30pm on the surface of the water 1.800.231.3236 or 707.285.2200 until it is strong enough to fly www.msmosquito.com away and feed. Protecting public health since 1915 FEEDING litter which may cause the pH level to A pH level of 6.5-8.0 in the water is become lethal. best. Inexpensive pH kits are available Established ponds will naturally supply at pool or pet stores. mosquitofish with their daily diet. However, when placing mosquitofish in It is against California Department of Certain pond design considerations newly constructed or recently cleaned Fish and Game regulations for private and regular maintenance may help water features where natural food is citizens to plant mosquitofish in waters minimize mosquito production. For Mosquitofish, Gambusia affinis, are absent, supplemental feeding ( i.e. of the State without a permit. (Title 14 example, aeration may discourage native to the southern and eastern fish flakes, crackers, stale bread, or CCR, Fish and Game Code, Section mosquito production because female parts of the United States. They crumbled dog food) is 1.63, Section 6400, and Section 238.5). mosquitoes aren’t likely to lay their eggs were introduced into California necessary. on turbulent water surfaces. Aeration in the early 1920’s for the control also creates water circulation, which of mosquito larvae. Mosquitofish After bacteria Generally, mosquitofish are stocked in will slow algae growth and increase continue to be an important and algae have small numbers because of their ability dissolved oxygen levels in the water. component of the Marin/Sonoma had time to build to quickly reproduce. Elevated dissolved oxygen levels are Mosquito and Vector Control District’s up in the water also beneficial for mosquitofish. Integrated Pest Management program. the fish will no Mosquitofish Stocking Rates Their voracious appetite for mosquito The water in newly established ponds longer need to be Ornamental Pond 4 to 6 fish larvae and pupae make these fish an supplied with additional must be treated to remove chlorine Swimming Pool 10 to 15 fish excellent alternative to insecticides in food. The continuation of supplemental that most cities add to drinking water. backyard ponds and other man-made feeding could actually decrease the Wine Barrel 3 to 4 fish You can purchase water conditioning water features. For more information on effectiveness of mosquitofish for Water Trough 4 to 6 fish treatment kits from your local pet shop obtaining these fish, call our office at controlling mosquito larvae. or pond and garden store. There is no 1.800.231.3236. Mosquitofish are extremely hardy, need to treat water used for topping off STOCKING FISH and can tolerate a wide range of a pond due to evaporation, as long as BIOLOGY temperatures. During the winter months the amount of water added is less than Mosquitofish are appropriate for use in these fish move to the bottom of the 20% of the pond’s total volume. The mosquitofish is a member of the ornamental ponds, water troughs, wine pond, become inactive, and do not barrels, neglected swimming pools family Poeciliidae. They do not lay feed. In most cases they will survive the VEGETATION eggs, but rather give birth to live, well and numerous other man-made water winter and become active again in the developed, and very active young. sources with a minimum water depth of spring when the temperatures rise. A pond with vegetation is both Mosquitofish breed throughout the 18 inches. aesthetically pleasing and beneficial summer with new broods of up to 100 Mosquitofish prefer sunlit areas of Pond Management when properly managed. Choosing the young produced at intervals of about ponds and do not thrive well in heavily correct type of vegetation is important six weeks. Young mosquitofish are shaded areas. This is important to These fish can also endure varying for the health of the mosquitofish as approximately ¼ inch in length and grow remember when deciding on the levels of organic content load. While they cannot survive in ponds where the to nearly three inches long. Mosquitofish placement of wine barrels or the there is generally no need to test the vegetation has taken over. Keeping the have insatiable appetites and are location of new ponds. Be mindful of pH level of the water on a regular basis, pond well-groomed will also help to capable of consuming up to three times areas such as under trees where the it may be necessary when stocking fish reduce mosquito production. Many pet their body weight, or 100-500 larvae, potential for heavy shade could occur, in new ponds or wine barrels because stores have products that help control per day. The average life span for a as well as the accumulation of leaf they have the potential to leach lime or vegetation and are safe to use with fish. mosquitofish is two to three years. other chemicals into the water.