Sarasota has discovered a new and innovative solution to an enduring problem: mosquitos. Instead of using pesticides, which are usually very harmful for the environment and human health, scientists are using sonic sound to destroy insect larvae and breeding mosquito fish to eat the grown insects. Sarasota Mosquito Control will be the first aquaculture facility in the state to breed mosquito fish.
“It’s a self-sustained type of mosquito control that we don’t have to go back and revisit with chemicals,” Eesa Ali, environmental biologist with Sarasota Mosquito Control, said in an interview with Channel 10 News. If pesticides are eliminated or even reduced it would undoubtedly benefit the surrounding environment as well as human health. Some pesticides can leach through soil and penetrate groundwater sources below. Half of the United States relies on groundwater for drinking, and almost 95 percent of households in rural areas use groundwater as their primary drinking source.
Each pesticide product has inherent risks associated with it, although they vary upon the particular chemical and use. Acute poisoning as well as long-term exposure to pesticides can result in death. Pesticides can also be the cause of natural resource degradation due to runoff into streams or groundwater sources. They can inadvertently harm wildlife including birds, fish and plants. Mistakes in the handling, storing, mixing and loading can also cause unintended contamination. The specific risk associated with a given pesticide or pesticide product depends on the toxicity of the compound and the probability of exposure.
“The risks of pesticide use in the environment depends on the persistence of the main players in the chemical cocktail,” aquatic biology and environmental science teacher at Castle View High School Jennifer Dallam commented. Along with teaching high schoolers for the past 19 years, Dallman is a Douglas County EMVIP 3.0 Sustainability Committee Faculty Lead (Energy Management Program) and Douglas County Water Resource Authority Supervisor. Dallman notes that pesticides can persist for varying amounts of time. “For example, Atrazine, a herbicide, lasts up to 220 days in wetland soils, while DDT lasts up to 30 years. If the pesticide persists and can move horizontally in surface or alluvial water or infiltrate ground water supplies, it has the potential to harm humans.”
Previously, technicians trapped the Gambusia affinis, or mosquito fish, in the wild, but this method risks an invasive plant or animal species being introduced to a new habitat or possibly a new disease spreading where immunities do not exist. Sarasota Mosquito Control is now breeding its own fish, and although most are currently empty, by summer the 1,700-gallon tanks will all be inhabited by mosquito fish. Technicians are also planning on using the fish waste to grow a garden.
“It saves us time, saves us money and we put less chemicals out in the environment,” Ali commented. Along with the environmental benefits, the fish are longer lasting than chemicals and therefore are a cheaper and faster solution. The fish are also known to thrive even in very poor water quality conditions and so will be of little maintenance. A female can give birth to as many as 400 fish every six weeks, and each grown fish can eat one to 1 1/2 times their body weight in mosquito larvae every day.
Despite the obvious benefits, introducing any nonnative species comes with risks. In addition to eating mosquito larvae, mosquito fish eat a variety of other insect larvae, zooplankton, aquatic plants and the eggs, larvae, and juveniles of various native fishes and amphibians. Mosquito fish are a regulated species in certain states and often illegal to introduce without a fish stocking permit. “Cane toads were introduced with the best intentions,” Dallman commented, writing that it is critical to consider “all the possible costs to the ecosystem before making a decision.”
If the plan is successful, Sarasota Mosquito Control’s director predicts the aquaculture program will save taxpayers $20,000 a year in trapping costs. Technicians are able to take the fish on service calls as well for those with need, completely free of charge, as it has been paid for by taxes.
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