SKEETER EATERS
L.A. County enlists little fish in a battle against a surge in mosquitoes
Outfitted in chest-high camouflage waders and tall rubber boots, Ryan Amick stepped cautiously into a murky artificial pond in South Los Angeles.
Ducks preened themselves on a small island and half a dozen turtles slid gently through the green water. Amick ignored them. He was there for the fish.
It was his second such excursion in a week, made necessary by the explosion of particularly aggressive mosquitoes throughout Los Angeles County.
Itchy residents placed nearly twice as many calls to the county’s bug police last month than they did the previous August, and it’s looking as though the trend will continue through September.
So Amick and his colleagues at the Greater Los Angeles County Vector Control District are fighting back — with mosquitofish.
The small, silvery creatures will be delivered to backyard fountains and ornamental ponds throughout the region to help limit the number of mosquito larvae that grow up to be flying, biting, disease-carrying adults.
“They are very good at what they do,” said Susanne Kluh, the district’s director of scientific services. “They are surface feeders, they don’t have very much in clean water requirements, and they breed in the most nasty conditions. That makes them a very useful tool.”
Vector control has used the fish to manage mosquitoes for decades.
But they’ve never seen demand like this.
“People are getting more bites than ever before,” said Kelly Middleton, the agency’s outreach coordinator.
In June, Middleton announced on the NextDoor app that her office was giving away the fish. Her phone lines blew up the next morning.
“We had so many requests at the beginning of summer that we had to contact the Orange County vector control office and ask if we could buy some fish from them,” she said. “They donated 5,000 fish to us to serve our residents up here.”
That infusion lasted through the end of July, but by August they had run out again.
Everyone hates mosquito bites, but the insects are more than just a nuisance; they can be dangerous. As they seek out hosts to provide their next blood meal, they can spread viruses such as Zika and West Nile.
In 2017, mosquitoes infected at least 553 Californians with serious cases of West Nile virus, leading to 47 deaths.
That’s why Amick was willing to get wet at Augustus F. Hawkins Nature Park.
He had already unloaded his gear: three large red coolers suitable for a tailgate party, canisters of dog food and fish flakes, and a long seine net with yellow foam floaters on top and small lead weights on the bottom.
Now he directed two of his vector control buddies as they set out to collect more fish.
Vector control specialist Larry Ballesteros struggled to keep his balance as he walked along the pond’s rocky shore holding one end of the net while Amick held the other.
“And there it goes,” Amick said as water trickled in over his waders. “I’ve got wet underwear now.”
The net formed a Ushape as the two men slowly dragged it through the pond. After they had gone about 10 feet, they swung it up like a hammock. Trapped inside were hundreds of 2-inchlong fish, all jumping and flipping like popcorn.
Jocelyn Analusia, anoth- er mosquito control technician, used a hand-held bait net to scoop the mosquitofish into the water-filled coolers.
They repeated the process two more times, sometimes tossing a few pieces of dog food into the water to get the fish’s attention.
When all three coolers were filled, Amick took a moment to examine the catch. He was pleased to see that very few fish showed signs of disease.
Satisfied, Amick snapped the coolers shut and stood up.
“They look great,” he said.
This pond is one of dozens that serve as holding tanks for mosquitofish.
Machado Lake in Harbor City and an artificial marshland in Carson are two of Amick’s favorite spots. Vector control also keeps stocks of mosquitofish in other ponds, lakes and public golf course water hazards across the county.
Any fish Amick collects are brought to vector control’s headquarters in Santa Fe Springs to confirm that they are in good health. Only then can they be delivered to residents eager to beat back the mosquito scourge.
Without humans, Los Angeles County would not be a very hospitable place for mosquitoes, Kluh said. The insects require standing water to lay their eggs, and we provide it.
Sure, she said, there might be some floodwater mosquitoes along the L.A. River in the spring and the occasional outbreak of saltwater mosquitoes along the coast after an especially high tide. But the bulk of mosquitoes that bite us today owe their existence to our overwatering.
“We call it ‘urban drool,’ ” Kluh said. “Without the urban drool, we would not have a mosquito problem.”
The county’s most common mosquito is called Culex. As mosquitoes go, it’s not a particularly bad one.
Lady Culexes need a blood meal to lay their eggs, but they’d rather bite birds than people. In fact, just 2% of all Culex bites involve humans. And because they are inclined to lay their eggs in dirty swimming pools and other fairly large bodies of water, they are relatively easy to manage — especially with the help of biological controls such as mosquitofish. A single female fish can eat as many as 100 squiggly, thread-like mosquito larvae in a day.
But over the last 10 years, a new type of mosquito known as Aedes has invaded Southern California. This one has Kluh and her colleagues at vector control worried.
Culex mosquitoes transmit West Nile virus, but Aedes mosquitoes can spread a host of potentially more dangerous diseases, including Zika, dengue fever, yellow fever and chikungunya.
Also, Aedes are more stealthy than Culex. They tend to bite people on their ankles, where they are less likely to be seen and slapped. And their larvae can survive in just one-eighth of an inch of water.
“We’ve found them in the depression of a chip bag that gets hit by a sprinkler,” Kluh said.
Aedes eggs can remain viable for years, even in dry conditions. Females attach them to hard surfaces like the side of a half-empty bucket or the edge of a plant saucer. When the vessel fills with water, they hatch.
Kluh said that if the Aedes population continues to grow, it won’t be long before being outside on a summer day will be just as uncomfortable in parts of Los Angeles County as it is in mosquito-infested regions such as Florida.
“In some places, it already feels like that,” she said. “People and kids are just covered in bites, and Los Angeles residents are absolutely livid.”
Shaun Crha is more of a gentle soul than the livid type, but he became so frustrated with the mosquito situation at his Bellflower home that he called vector control to see if they could help.
“In less than 15 minutes of playing outside with the dogs, I’d get a half-dozen bites,” he said. “At first I thought we had fleas in the yard.”
Crha, an interior designer, and his husband recently remodeled their spacious frontyard with broad cement pavers, a fire pit, couch seating and droughttolerant plantings of olive trees, rosemary, lavender and salvia. They also installed a 3-foot-wide fountain.
Crha worried that the fountain might be the source of his mosquito problem. He also feared he was creating mosquito problems for his neighbors.
When Amick arrived at Crha’s home, he knelt by the new fountain and aimed his f lashlight along its edge. The moving water would probably preclude Culex mosquitoes from laying their eggs, Amick said, but Aedes mosquitoes could attach their eggs to the fountain’s wall and the larvae could survive along the edge where the water was calm.
Amick asked Crha whether the fountain ran all night. Crha said it didn’t. Then Amick pointed out an area where the water remained still, even when the fountain was on.
“Some hearty mosquitoes might be able to survive in those areas,” he said.
Convinced that his silver mosquito killers could be of service, Amick dumped seven of them into the water, where they quickly disappeared from sight.
“You don’t have to feed them. You don’t really have to do anything,” he told Crha. “If they start dying, give me a call.”
Then Amick searched the entire yard for standing water, examining buckets, rain barrels, storm drains and backyard trash. He dumped the saucers beneath two large pots on Crha’s front porch and turned them upside down. The rest of the yard passed inspection.
Before leaving, Amick gave Crha some pamphlets, advised him to use an insect repellent with DEET, and asked him to share the advice with his neighbors.
“The invasive mosquito in L.A. County is a new fact of life,” Amick said. “We have to learn to live with it and protect ourselves from it.”