The threat of West Nile virus has caused stewards of standing water around Tucson to take extra care to ensure mosquito populations are kept under control. Two human cases of West Nile have already been recorded in Pima County this fall. Next summer, several species of endangered fish may be drafted to help reduce mosquito populations at wetland locations around the Tucson valley.
Last week, the Arizona Daily Star reported that state officials are currently finalizing an agreement under the Endangered Species Act that would allow the reintroduction of the Gila topminnow, Yaqui topminnow, desert pupfish and Quitobaquito pupfish into selected wetlands to begin controlling mosquito populations.
In the past, private owners of ponds and other wetlands could not purchase endangered native species because of the provisions of the Endangered Species Act, which were intended to protect the fish. Ironically, the disincentives created by prohibiting collection and the stringent regulations surrounding wild populations prevented many landowners from working to restore endangered species.
To encourage voluntary conservation, former Secretary of the Interior Bruce Babbitt introduced "safe harbor" agreements like the one currently being reached by state officials for the endangered fish. These agreements protect landowners who voluntarily engage in species restoration efforts from penalization if some of the specimens die.
And losing endangered species to die-offs is a big concern. Tucson Water hydrologist Bruce Prior told the Star that Tucson Water had considered using endangered fish at the city-managed Sweetwater Wetlands, but declined to do so for fear of being held responsible should a fish die-off occur.
Sierra Vista may use endangered fish in its sewage treatment plant. Current efforts by Sierra Vista officials to spray insecticide on the artificial wetlands outside the treatment plant are proving ineffective because bulrushes and cattails have grown so thick that many larvae are escaping the spray.
Ironically, according to the Star report, Sierra Vista had previously considered using the mosquitofish ÷ a non-native, invasive species whose introduction into Sonoran Desert wetlands is one of the top reasons for the demise of the endangered Gila topminnow ÷ to control mosquito populations.
The ability of the topminnow and pupfish to control mosquito populations illustrates how protecting endangered species can reward good stewards of the environment. The intricacies of natural food chains are not fully understood and serious environmental problems often occur when important links are removed from biological cycles. The failure of chemical pesticides to cure the growing problem of mosquito infestations spreading West Nile virus shows that man has not yet outsmarted nature.
The UA has a pond of its own, which is likely to require mosquito remediation next summer as well. While UA officials have yet to join the safe harbor agreement, the fishpond, located near Park Avenue and North Campus Drive, would be an excellent location for endangered topminnow and pupfish to be reintroduced.
Local water gardeners are also interested in using native fish in their fishponds to control mosquito populations. According to the Star, at least 12 members of the Tucson Water Gardeners group are interested in participating in the safe harbor agreement. Turning local pond owners away from pesticides and invasive species while reducing mosquito populations is something many water gardeners realize will benefit everyone.
Some conservationists have raised concerns that reintroduction efforts will be unsuccessful and could reduce already-low populations of endangered fish, but some stocks will be kept in captivity for future releases. Doug Duncan of the U.S. Fish and Wildlife Service explained that fish are much easier to propagate than other endangered species and are actually "pretty prolific," given the right conditions.
Most importantly, the reintroduction of endangered native fish to cure a new environmental problem should act as an example to the public that natural ecosystems work best with all of their components. Should the fish species prosper, mosquitoes will be kept under control and the risk of human West Nile cases will be greatly reduced. Wildlife agents will also be compelled to exterminate invasive non-native species that threaten native species like the mosquitofish. It is a win-win situation from all directions.
The UA should consider using endangered topminnow and pupfish to control mosquitoes in the Park Avenue pond. It is an opportunity that should not be missed.
Kendrick Wilson is a political science junior. He can be reached at lletters@wildcat.arizona.edu.