Mosquito control in wastewater: a controlled and quantitative comparison of pupfish (Cyprinodon nevadensis amargosae), mosquitofish (Gambusia affinis) and guppies (Poecilia reticulata) in sago pondweed marshes.
In California, the abilities of pupfish, mosquitofish and guppies to control mosquitoes in wastewater marshes were compared (using an experimental system of tanks containing waste water and Potamogeton pectinatus; initially larvae of Culex tarsalis were used, but as these proved unsuitable, larvae of C. pipiens were substituted as test organisms). All species of fish reduced mosquito emergence. When fish population densities were similar, fish reduced emergence to similar levels. As experiments progressed, guppies developed greater population densities and provided better mosquito control than mosquitofish, which developed greater densities and better control than pupfish. Fish also reduced numbers of zooplankton, and guppies increased total plant biomass, suggesting that fish may influence the ability of wastewater marshes to 'treat' wastewater.