The use of native fishes for vector control

Authors: Douglas K. Duncan

Year: 2012 (xliv)

Abstract

Western mosquitofish Gambusia affinis have been introduced world-wide, ostensibly for control of mosquito larvae. The negative impact of mosquitofish on native fishes across the globe is well documented. Other studies show mosquitofish also negatively impact tadpoles, newts, frogs, and aquatic insects. Several studies have demonstrated that mosquitofish carry parasites and disease that can be transferred into new areas. Lastly, mosquitofish are also known to cause cascading changes aquatic systems functioning. A need exists to provide mosquito control for public health and safety. While we can argue about the effectiveness and need for mosquito control, society demands it. So, any efforts to minimize the negative effects that flow from vector control are worthy ones. The use of native fish for mosquito control is rare, including the southwestern United States, and Arizona particularly. Gila topminnow Poeciliopsis occidentalis has been shown to be as effective for mosquito control as mosquitofish, as has the desert pupfish Cyprinodon macularius. The Arizona Game and Fish Department, U.S. Fish and Wildlife Service, and the U.S. Bureau of Reclamation in Arizona have championed the idea of using native fishes to control mosquitos. However, socio-political and regulatory hurdles are many. For endangered (and threatened) species like the Gila topminnow and desert pupfish, the hurdles are even greater, but not insurmountable. Despite these hurdles, the Arizona Game and Fish Department and U.S. Fish and Wildlife Service are attempting to facilitate the use of desert pupfish and especially Gila topminnow for mosquito control. We have a willing partner in Pima County’s Natural Resources, Parks, and Recreation Department and the Health Department. Progress is slow. Because of climate change induced ecosystem changes, expanded mosquito populations and expanded mosquito seasons may occur in Arizona and the other southwestern United States. In addition, existing tropical and subtropical diseases, or novel diseases, may move north into these areas. The demand for vector control will increase, and we hope it can be accomplished with native fishes.