Mosquitofish: A natural tool to combat Lee and Collier's pests
Mosquitoes are the unwanted guests of nearly every Floridian’s outdoor forays.
As Southwest Florida’s rainy season gears up, these bloodsucking pests will be buzzing about looking for standing water to lay eggs.
While the Collier and Lee mosquito control districts readily advise residents to vigilantly dump sources of standing water, some areas such as abandoned pools or backyard swales aren’t easily drained.
To combat the problem, both districts deploy a natural predator: the Gambusia holbrooki.
Gambusia, or more commonly, mosquitofish, are the 2-3-inch relatives of guppies, but with a voracious appetite.
“They are native to here and very well known and loved,” Nora Demers, associate professor of biology at Florida Gulf Coast University, said. “They’re the good guys. They’ve evolved with our ecosystem and are a natural part of it.”
A 2018 report, mandated by the United States’ Global Change Research Act, says climate change is expected to make conditions more suitable for disease-carrying mosquitoes in southern Florida.
Conditions are already suitable for the Aedes aegypti species, which can spread dengue, chikungunya and Zika, the report says.
“The Southeast is the region of the country with the most favorable conditions for this mosquito and thus faces the greatest threat from diseases the mosquito carries.”
The report predicts a permanent, year-round breeding season if management strategies are not put in place.
Enter the mosquitofish, a tool in local efforts to fend off the pests.
Collier's curbside pickup
At the Collier Mosquito Control District, two 800-gallon tanks store mosquitofish. The district raises them for residents who may apply through the district website and pick them up for free.
“People can make an appointment to pick up the fish from one of our biologists,” district spokeswoman Robin King said. “The biologist will determine how big of a space the resident has, what it’s needed for, and how many fish they need.”
Last year, Collier’s district gave out 4,000 mosquitofish with its curbside pickup.
“We’re seeing that we are getting repeat people coming back every year because they are finding they definitely help,” King said. “It’s a really nice biological control method.”
For now, orders have been slow, but King said the demand will increase as rainy season picks up.
This is the district’s third year raising mosquitofish and King said they upgraded their storage capacity after the first year since it was so popular with residents.
“It’s definitely something the public is interested in, but we’re not at the point where we have the capability to send fish out with techs for distribution,” King said.
Lee's gambusia program
The Lee Mosquito Control District works in partnership with the county’s Hyacinth Control District to raise its mosquito fish, spokesman Eric Jackson said.
The Lee district’s spot treaters and scientists will survey the county for certain sites where mosquitofish would be a good option.
“When you have a body of water that has no other natural aquatic predators in it, that’s where they’re mostly effective,” Jackson said. “A ditch growing larvae with no other predators may be a good application or it could be even abandoned swimming pools with no chlorine or chemicals.”
Mosquitofish won’t take care of the entire problem, Jackson said, and stocking mosquitofish in some areas isn’t beneficial.
“A retention pond in a community that already has fish wouldn’t benefit,” Jackson said. “Chances are the mosquitofish would just get eaten.”
It’s likely the retention pond wouldn’t be growing mosquitoes anyway, he said. Larvae are more likely found in containers around the outside of the house.
While gambusia can reduce mosquito larvae, they also benefit the natural environment as part of the food chain.
“Mosquitofish are food for another fish or food for a bird,” Demers said. “They’re native to our region and they belong here. The only problem is there are not enough of them for the bigger fish to eat.”
Karl Schneider is an environment reporter. Send tips and comments to firstname.lastname@example.org. Follow on Twitter @karlstartswithk