Morgan Ford, a UW alumnus in Wildlife and Fisheries Biology Management gave a presentation on the Impacts of Mosquito Control on Insects in Spring Creek yesterday. Other invertebrates and ecosystems can be collateral damage in pesticide application.
Ford was presented by his advisor, Invertebrate Zoologist Lusha Tronstad. The research that Ford conducted and analyzed during 2013 focused on the impact of Permethrin, an insecticide, on other aquatic invertebrates.
“We wanted to see the effect on non-target invertebrates in Spring Creek,” Ford said. “By non-target invertebrates I mean the mayflies, worms and everything else besides the mosquitos.”
“They are trying to kill mosquitos in the terrestrial stage, the ones that fly around and bite,” said Tronstad.
There are three primary reasons that mosquito control is important. The first reason is that they are a nuisance and no one likes getting bit by them. The second is economic, as property values can go down if there are large amounts of mosquitos present. The third reason is mosquitoes are carriers of certain diseases.
Mosquitos can carry malaria, yellow fever and the West Nile Virus. This specific mosquito control program is focused on the West Nile Virus.
Studying the effect on the non-target invertebrates is important because Spring Creek supports a year round population of Brown Trout and is an essential spawning habitat for trout from the Laramie River.
“Permethrin can reduce the amount of invertebrates that live in the stream,” said Tronstad.
Ford said reducing the amount of invertebrates may alter the fish population’s diet.
“By limiting a food source, you are essentially limiting the organism that feeds on the food source,” said Ford.
“It could potentially affect the fish in Spring Creek, the birds that specialize in aquatic insects and amphibians which are very sensitive to things like that (Permethrin),” said Tronstad.
“By reducing the amount of algae and plant eating bugs, you can get an overabundance of algae and undesired vegetation,” said Ford.
It is considered poor water quality if there is too much algae present and also infringe on Brown Trout’s habitat.
Ford predicted that they would see an increase in biomass drift following an application of Permethrin. They measured three different sites at three different intervals.
They were looking at the drift of the invertebrates. Drift is described by Ford as invertebrates either trying to get out of an unsuitable environment or they were dead and just floating downstream.
Ford found that there was a significant increase in biomass drift immediately following the application of Permethrin.
The drift levels returned back to pre-application levels on the third measurement of the water.
Ford said that they were not able to determine if the invertebrates were alive or not, because it would be too much to quantify.
Ford is not involved in whether the application of the pesticide is good or bad.
“We see that there is a pesticide application and we want to see what the effects are,” said Ford, “We are just looking at the science.”
