Do eastern mosquitofish exhibit anti-predator behavior towards red swamp crayfish?

Anti-predator behavior has been described in many freshwater fish species. Freshwater crayfish may have a great impact on prey species through behavioral changes. The eastern mosquitofish, Gambusia holbrooki, and the red swamp crayfish, Procambarus clarkii, are native to North America, and have been introduced worldwide, causing negative effects on aquatic ecosystems. The interactions between these exotic species are poorly known. In natural habitats P. clarkii consumes G. holbrooki, but it is not clear if the mosquitofish has anti-predator defenses against the crayfish. The main objective of this study was to determine if G. holbrooki exhibits anti-predator behavior in the presence of P. clarkii. To address this question, laboratory tests were performed in experimental aquaria, analyzing the following behavioral traits of the mosquitofish: activity, distance from the predator, and space use. The mosquitofish were generally active and mainly preferred open space in both controls and treatments. Results suggest that G. holbrooki does not display anti-predator behavior when exposed to P. clarkii under the laboratory conditions used in this study.