Efficacy of artificial refuge to enhance survival of young Barrens topminnows exposed to western mosquitofish
Correspondence to: J. T. Westhoff, Missouri Cooperative Fish and Wildlife Research Unit, University of Missouri, 302 ABNR Building, Columbia, MO 65211, USA. E-mail: firstname.lastname@example.org
- Artificial refugia have been implemented in freshwater and marine systems to increase structural complexity and achieve a variety of fisheries management goals. The use of artificial refuge to promote coexistence between an invasive species and a native species has not been widely studied but may serve as a viable management option.
- Range expansion of the invasive western mosquitofish, Gambusia affinis, across the Barrens Plateau of Tennessee has contributed to local extirpations of the native Barrens topminnow, Fundulus julisia, from parts of its historic range. Recent laboratory and field observations suggest that young topminnows may be vulnerable to injury from, or predation by, mosquitofish in the wild.
- In this study, an artificial refuge was tested in the laboratory and in situ to determine if it could increase survival, growth, or recruitment of juvenile topminnows exposed to mosquitofish.
- Adult topminnows and small mosquitofish caused negligible mortality to juvenile topminnows regardless of refuge presence in the laboratory trial. However, topminnow 20-day survival in the presence of large mosquitofish was 13% when refuge was present and 7% when refuge was absent. Juvenile topminnow growth did not differ among treatments indicating that the addition of refuge or the type of potential antagonist did not significantly affect topminnow growth.
- Field trial results showed no statistical differences in the number of juvenile topminnows captured at sites with refuges and those without, except during July sampling. In both trials, juvenile topminnows were observed to use the refuges, but no evidence exists that would indicate refuges are a feasible management tool for promoting the coexistence of topminnows with mosquitofish. Copyright © 2012 John Wiley & Sons, Ltd.