Importance of Mosquito Control

Over the past several years, the mosquito has metamorphosed from pesky summertime nuisance to serious public health threat. The rapid spread of West Nile virus and St. Louis encephalitis has transformed management of mosquito populations from pest control to public health necessity. According to the Center for Disease Control, as of January 2003 more than 250 people have died of West Nile virus in the United States; several thousand more "laboratory-positive human cases" were confirmed. Reported cases of other mosquito-borne diseases, including malaria and dengue, are also on the rise in the United States.

Role of Gambusia affinis in Mosquito Control

Increasing awareness of the necessity of controlling mosquitoes -particularly in the larval stage-- has coincided with concern over the widespread use of pesticides to combat disease-transmitting vectors.

Environmental scientists warn that the pesticides most frequently used to combat West Nile disease carry their own toxicity risks, and repeated use of the chemicals may reduce their effectiveness when those chemical agents must be used as a last resort. In this scenario, biological control, or the use of biological organisms to control pests, has become one of the most important weapons in the war against mosquito-borne disease.

The Center for Disease Control opines that biocontrol may become a more important tool and play a larger role in mosquito control in the future. CDC further states that the most effective and economical way to control mosquitoes is by larval source reduction; control of adult populations by aerial application of pesticides is usually a last resort.

What is Gambusia affinis?

Gambusia affinis, appropriately named the "mosquito fish," is a small, guppy-like fish ranging in size from approximately ¾ to 1 ½ inches long. As its name implies, it is a natural predator of mosquito larvae.

Larvae Consumption

Gambusia affinis is a voracious predator. According to statistics cited in U.S. Navy research, a large female Gambusia is able to consume 225 larvae within a one hour period, and a pair of half-grown Gambusia are capable of consuming over 5000 larvae in 11 weeks. All sizes of Gambusia feed on mosquito larvae; even fry only a few hours old will attack young instars.

Reproduction Capabilities

Gambusia bear live young, producing an average of three to four broods per summer at intervals of three to six weeks. The number of fry per brood averages between 25 and 125. Reproduction usually occurs during the warmer spring and summer months.

Cold-Tolerant Gambusia

More than 30 years of natural selection by Fattig Fish has resulted in a genetically adapted cold-tolerant stock of Gambusia affinis able to survive temperatures below -30° and to 100° Fahrenheit. This special cold-tolerant strain is particularly well-suited to climates above the 39th parallel, where winter temperatures often prevent overwintering of Southern Gambusia. Additionally, the cold-tolerant strain has been observed to feed at 50° water temperatures, a distinct advantage over other strains, which generally begin to feed at considerably higher temperatures.

Desirability of Cold-tolerant Gambusia affinis

The mosquito fish is an ideal form of biological control. It is a hardy and adaptable fish, tolerant of a wide range of salinity and temperature variations, and presents a cost-effective, safer alternative to pesticides. With its prolific quality and ability to overwinter, an investment in Gambusia affinis brood stock now will result in future mosquito control benefits.

Optimal Stocking Considerations

Gambusia affinis can generally be shipped from early spring through late fall. Placement of these biological agents in early spring, however, enables them to begin consuming mosquito larvae as soon as the larvae begin to hatch in late spring.

Shipping Information

Pre-adult cold-tolerant Gambusia affinis are packaged in quantities of 1000 per box or according to purchaser specifications. They can be shipped by FedEx or UPS anywhere in the continental United States with guaranteed live delivery.

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SEE how the State of New Jersey has utilized our mosquito fish in a successful long range control program. This page addresses many of the questions and concerns of those seeking to safeguard the public or their families against West Nile Virus. http://www.nmca.org/Nmca94-16.htm

Gambusia effectiveness in NJ (1996 update)

New Jersey Biological Mosquito Control Program

Overkill: Why Pesticide Spraying for West Nile Virus May Cause More Harm Than Good

About.com's Mosquito Fish information page

Mosquito Fish wiki

Species Summary: Gambusia affinis Mosquitofish http://fishbase.org/Summary/speciesSummary.php?genusname=Gambusia&speciesname=affinis

NAS - Species Fact Sheet - Gambusia affinis
http://nas.er.usgs.gov/queries/FactSheet.asp?speciesID=84

National Mosquito Control Assn. www.nmca.org