NEW ORLEANS (AP) – In a large above-ground pool here, entomologists are breeding front-line mosquito fighters.

Hiding in the fibrous root systems dangling in the brown water, these fighters – hundreds of inch-long, guppy-like minnows – are being raised to be deployed to thousands of festering, flooded-out pools, ponds and hot tubs abandoned in New Orleans and the Gulf Coast since Hurricane Katrina.

Their mission: devour mosquito larvae and, potentially, prevent the spread of diseases like mosquito-borne encephalitis and the sometimes deadly West Nile virus. In the process, they’ll help minimize one of this region’s most annoying summer pests.

The fish have been used to control mosquito populations since the 1930s, but this post-Katrina offensive marks the first time they’ve been harvested by the thousands for deposit into pools that have become scummy breeding tanks for mosquito larvae.

The abundance of standing water and hot summer temperatures can create a mosquito-breeding haven. And with as many as 6,000 abandoned pools in New Orleans alone, mosquito experts say the tiny fish are their biggest allies in protecting the Gulf Coast from a nasty mosquito infestation.

“Just a bucket of water can breed thousands of mosquitoes,” said Ashley Gray, a college student interning this summer with the mosquito control board.

The mosquito fish, which are native to the region, are surface-breathers and capable of surviving in polluted waters with low oxygen levels. Their primary food source is mosquito larvae, though they also can live off algae.

Fast reproducers, one female can give live birth to up to 100 babies every 30 days or so. Each can gobble as many as 100 mosquito larvae a day.

The fish can survive for years and will eat their young if the population gets too high, reducing the risk of overpopulation, said Steve Sackett, another research entomologist for the mosquito control board.

Sackett and his team, with about a dozen volunteers, have put fish into more than 1,000 pools since April 17.

In some cases, they found pools that already had fish living in them, deposited from ditches and other waterways during the massive flooding that followed the August storm. Some pools also have become home to other natural mosquito predators like beetles, frogs, turtles and aquatic insects.

“The pools have become ponds,” Sackett said.

So far this year, a severe drought has helped keep mosquito larvae to a minimum, and there have been no reports of West Nile virus in Louisiana, according to the Centers for Disease Control and Prevention.

But there have been at least four reports of West Nile in humans in other states: two in Texas, one in Mississippi and one in Colorado.

Last year, Louisiana had 188 West Nile virus cases, including 11 deaths. The state’s worst West Nile season was in 2002, when it had 329 cases and 25 deaths.

Now that the summer heat has set in, mosquitoes are laying eggs, and mosquito control officials say they’re concerned about what will happen when the drought ends and the Gulf Coast starts getting more rain.

“If we get into a period of heavy rainfall, all the containers – containers in abandoned yards, toys, boats and everything else that can hold water – are perfect reservoirs for mosquito breeding,” Sackett said.

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Centers for Disease Control and Prevention: http://www.cdc.gov