Western Mosquitofish Predation on Native Amphibian Eggs and Larvae

ABSTRACT

The western mosquitofish (Gambusia affinis) is commonly stocked for mosquito control, but this species has the potential to negatively impact native amphibians through predation on early life stages. We examined predation by western mosquitofish on eggs and larvae of wood frog (Rana sylvatica), American toad (Bufo americanus), eastern tiger salamander (Ambystoma tigrinum tigrinum), and western chorus fiog (Pseudacris triseriata triseriata) using a series of laboratory microcosm experiments. There were no eggs of any amphibian species consumed by western mosquitofish, and only one predation attempt was observed on a western chorus frog egg. No predation was observed on larvae of wood frog or American toad, and there was no significant difference in the percentage of larvae of these two species missing at the end of the experimental trials (11% and 6%, respectively). However, eastern tiger salamander and western chorus fiog larvae experienced significantly higher predation rates than the other two amphibian species, with approximately 59% of tiger salamander and 92% of chorus frog larvae missing at the end of the experiments. Based on these results, we do not recommend stocking western mosquitofish into waterways that contain early life stages of native amphibian species.