Abstract

Pesticides targeting mosquitoes are increasing in use as the mosquito population continually poses a threat and a nuisance to residents and animals. However, as the use of pesticides increases there is a need to investigate the effects that these pesticides have on the marine environment. Four bioassays were conducted to determine if the pesticides used for mosquito control in the Florida Keys, Biomist 30/30 ® and Dibrom ® , are affecting the recovery of Strombus gigas. The bioassays tested the effects of each pesticide on embryogenesis and veliger survival. Three concentration levels were tested: the target spray concentration used by mosquito control, half the target concentration, and twice the target concentration. Embryonic development was determined by measuring the perivitellin space of developing embryos. Larval survival was determined by counting the number of veligers swimming in the water column after 48 hours of exposure to the pesticides. Embryos exposed to the pesticides exhibited delayed or abnormal development while embryos in the controls showed normal development. Larvae exposed to Biomist 30/30 ® had 100% mortality after 48 hours. Unfortunately, all the larvae (including those in the control) in our Dibrom ® bioassay crashed after 24 hours. These results may have implications for continued coastal development in the Florida Keys, as the pesticides used in mosquito control may be negatively affecting the recovery of nearshore queen conch populations.

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