New Jersey Employs Unique Fish To Battle Mosquitos

Department of Environmental Protection employees are busy this spring stocking many of New Jersey's lakes and ponds with thousands of unique species of fish. But it's not with anglers in mind. It's all about the impending annual battle with the State's pesky crop of mosquitoes.

On the front line of that battle, fighting to safeguard State residents from those biting bugs, are Gambusia affinis, Pimephales promelas, Fundulus diaphanous, Lepomis macrochirus, and Lepomis gibbosus, otherwise known as Gambusia, fathead minnows, freshwater killifish and pumpkinseed sunfish.

They're small fish with big names and even bigger appetites -- at least when it comes to mosquito larvae.

The DEP's Office of Mosquito Control Coordination, in partnership with county mosquito control agencies, has stocked its three millionth fish this year as part of its biological control program to combat mosquitoes, according to Bob Kent, administrator of the DEP's Office of Mosquito Control Coordination.

"These fish make excellent mosquito deterrents, and can be more effective than pesticides,'' Kent said. "Insecticides require multiple applications every mosquito season; the right fish can eliminate or greatly reduce the need for any applications at all. For every acre of mosquito habitat controlled by fish, an acre does not have to be sprayed with insecticide.''

Their effectiveness is partly due to their reproductive habits, explained Claudia O'Malley, the office's technical advisor. Mosquitofish, she noted, can start reproducing at just six weeks old, and then reproduce every four weeks.

"So you can build up a pretty good population quickly," O'Malley said. "This sustained population can continuously keep mosquitoes at bay without any need for insecticides.''

The program is supported by the state Mosquito Control Commission and the Bureau of Fresh Water Fisheries, which raises the fish that are used as bio control agents at the Division of Fish and Wildlife's Charles O. Hayford Hatchery in Hackettstown. The Bureau is providing its three millionth fish this year in the 20th year of the program, which began in 1992. They are offered to participating counties at no cost to them, and have been stocked at sites in all 21 counties since the program's inception.

Potential stocking sites are first scouted by biologists from the Office of Mosquito Control Coordination to determine which, if any, species of mosquito-fighting fish would be best suited for a particular location. Also considered by biologists are the potential impacts of mosquitofish, which are omnivores, on other native fish in potential stocking areas.

In those areas where Gambusia are not appropriate, the bio control program uses other species including the fathead minnows, freshwater killifish and bluegill sunfish. In most years, these species are stocked in even greater numbers than the Gambusia affinis.

For more information on the State's mosquito programs, visit:

For tips on reducing mosquito activities around your home this spring and summer, visit:

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