Mosquito Fighters Target Popular Lake

To nature lovers, fishermen and picnickers, Harbor Regional Park’s 23-acre lake is a sanctuary amid a sea of highways and high-rises.

But to some state and local officials, the lake is seen not so much as a haven for pleasure seekers as a home for mosquitoes that breed along the lake’s swampy, weed-infested shoreline and pose a health threat.

“It’s one of the largest sources in the Los Angeles metropolitan area for disease- and non-disease-carrying mosquitoes,” says Charles Myers, a public health biologist with the state Department of Health Services. “All the ingredients for mosquitoes are at Harbor Lake.”

“It’s just a natural spot for mosquitoes,” adds A. C. Estes, who serves as the City of Los Angeles’ representative on the Southeast Mosquito Abatement District Board of Trustees. “The lake simply attracts mosquitoes because of its ecology.”

The abatement district warned that it will not be hesitant about using its powers to control disease-carrying insects at Harbor Regional Park.

Now, however, the abatement district says it is determined to put a large dent in the park’s mosquito population, which is believed to have increased in recent years as maintenance of the area’s swamps and weeds has declined.

Appeal for Action

The district, fearing a repeat of last year when encephalitis-carrying mosquitoes were discovered at the 230-acre park, has appealed to the Los Angeles City Department of Recreation and Parks, which is responsible for operating and maintaining the park, to take action to permanently control the problem.

Moreover, district officials say that they have warned the city that the district will not be shy about using its enforcement powers to get the job done. Under state law, the district could fine the city $500 a day for every day it believes a public health problem exists.

“We’re not raising the red flag and saying we are going to have an encephalitis outbreak the day after tomorrow,” Estes says. “We do feel, though, that this is a threat to the public health and we can’t afford to let it go. And we believe recreation and parks must assign a higher priority to this thing than they have (in the past).”

Several abatement district officials say that their get-tough stance stems from the fact that there were more than 20 cases of encephalitis reported in Los Angeles County last year. One case was contracted by a man living near Harbor Lake, the officials say.

Also, the district’s concerns have been heightened because last fall it discovered that there were mosquitoes at the lake carrying the virus. The find was made after the district placed a “sentinel” flock of chickens near the water.

Chickens are used because mosquitoes prefer to feed on poultry. If the animals are infected, they do not suffer symptoms of the disease, but their blood shows signs of the virus.

“We have been telling the department for the past 14 years that there was the possibility of disease-transmitting mosquitoes in the area and it finally occurred,” says Jack Hazelrigg, an entomologist with the district.

The abatement district’s effort to persuade the city to find a solution to the lake’s mosquito problem comes a time when a program aimed at improving the lake’s fishing is nearing completion. In all, $1.2 million in state funds was allocated to the Recreation and Parks Department to dredge a portion of the lake, install an aeration system, clean up the shoreline and construct a new dam.

While state Fish and Game Department officials have already planted about 4,000 catfish in the lake as part of the program, they have agreed, at the request of the abatement district, to delay planting bass until this summer or fall. The district was concerned that the bass could add to the mosquito problem because the fish feed on gambusia, or mosquito fish, which eat mosquito larvae.

Real Concern

“Naturally, we were somewhat reluctant to halt any of our activity when we were first contacted,” explained Keith Anderson, a fisheries management supervisor for the department. “But it’s probably the best thing to do because there is a bona fide public health concern. When we have a public agency saying there is a problem, we have to accept their expertise.”

Recreation and parks officials say they agree with the abatement district that the mosquitoes are a problem. But they say the department has been careful to consider the concerns of environmentalists, who have complained that any large-scale removal of bulrushes to give mosquito fish a better chance to forage could destroy or harm the nesting habitats of some wildlife and birds such as the least bittern.

In addition, the officials say, the department’s maintenance efforts at the lake have been affected in recent years by decreases in personnel and funds.

As an example, the officials say, the department purchased an amphibious machine in 1977 to control the mosquitoes by cutting paths between the bulrushes to allow the mosquito fish to forage. But after the passage of Proposition 13 in 1978, the operation was curtailed because of a loss of manpower, and the bulrushes grew back at an even greater density.

‘Mud Cat’ Machine

Nevertheless, recreation and parks officials say that because of the abatement district’s latest concerns, the department recently purchased a barge-like vehicle called a “mud cat.” The machine, which is now being used around the lake’s shoreline, is capable of cutting bulrushes off about 18 inches below the water level.

In addition, Gat Lum, a senior recreation director for the deparment who supervises operations at Harbor Regional Park, says recreation and parks has requested that California Conservation Corps workers be assigned to help cut the bulrushes at the northern end of the lake to allow stagnant water to drain or dry up. She predicted that the workers could start by late April or May, well in advance of the hot months when mosquitoes pose the most serious threat.

Lum, as well as the abatement district, say the two efforts should help control the mosquito population at the park this year. But they say the work will not offer a permanent solution to the mosquito problem, a view shared by Councilwoman Joan Milke Flores, who represents the area and has discussed the mosquito problem with both sides.

“I think (the mosquito problem) is serious enough that at this point we have to talk about the long-term solution,” Flores said. “I don’t think it is a question of maintaining the status quo or putting a Band-Aid on the problem. It is my feeling we should discuss the long-term solution in terms of the worst-case scenario.”

Reviewing Several Plans

Lum said the department’s planners are now reviewing several plans. The district has suggested that an earthen dam be erected across the outer fringe of the vegetation in the northern part of the lake, where the bulrushes are the thickest.

According to the district, the dam would separate the main portion of the lake from the area where bulrushes are dense, and a drainage pipe could be then installed to carry summer runoff water to the main lake. The bulrush area could then dry during the summer, they say.

Besides the dam proposal, Lum said, the department is studying the feasibility of removing bulrushes by dredging that portion of the lake left untouched when work was done for the fish-enhancement program, and filling in some of the problem areas of the lake with dirt.

Lum said she is not certain when the department and the abatement district will meet to decide on a solution. And while no price tags have been discussed, she estimated that any one of the solutions suggested could cost about $500,000--money the department does not have.

Flores, however, said she will seek funding once the department and the abatement district come to an agreement. “What I need is for someone to outline to me exactly what the need is and what it is going to cost,” she said.