Tilapia, mosquitofish, sailfin molly, and largemouth bass are among the most detrimental exotic fishes. These introduced species affect desert pupfish through their predation, competition, aggression, and behaviors. Some of these nonnative fishes became established after escaping from fish farms or being released by well-meaning pet owners. Tilapia were introduced into irrigation drains and canals in attempts to control vegetation, while mosquito abatement districts use mosquitofish for mosquito control. Two other exotic pests that adversely affect desert pupfish are bullfrogs and salt cedar.
Bullfrogs are native east of the Rocky Mountains and they prey upon pupfish here in California.
Salt cedar is a plant that is native to the Middle East. Salt cedar has a high transpiration rate, which during critical dry seasons, leaves insufficient water for native species. Sharon Keeney is a fishery biologist in the Department of Fish and Game's Region 6.