The role of intraguild predation on potential impacts of invasive mosquitofish, Gambusia affinis, on Ash Meadows pupfish, Cyprinodon nevadensis ssp.

Authors: Samantha M. Skinner, Brady A. Holte, Sujan M. Henkanaththegedara, Craig A. Stockwell

Year: 2012 (xliv)

Abstract

Our previous work (Henkanaththegedara & Stockwell, 2012, Ecol. Freshwater Fish, DOI: 10.1111/j.1600-0633.2012.00587.x) showed that intraguild predation is a potential mechanism for the co-existence of native fish species with non-native western mosquitofish, Gambusia affinis. Mosquitofish have invaded many springs in Ash Meadows National Wildlife Refuge, a ‘hot spot’ for endemic species, posing a potential threat to endemic fish. However, pupfish, Cyprinodon nevadensis ssp., native to Ash Meadows co-exist with non-native mosquitofish in many springs. We conducted laboratory predation trials to investigate the role of intraguild predation between non-native mosquitofish and pupfish using a surrogate species, Sheepshead minnow, Cyprinodon variegatus. Both male and female mosquitofish predators significantly reduced larval sheepshead minnow prey survival compared to the control (3.3% and 6.7% survival, respectively; Á·²= 61.26; d.f. = 2; p < 0.0001). By contrast, sheepshead minnows had limited predation on mosquitofish larvae. Male sheepshead minnows did not prey on larval mosquitofish prey. However, female sheepshead minnow predators significantly reduced larval mosquitofish prey survival to 86.7%(Á·²=8.43; d.f. = 2; p < 0.05). Our results suggest that mosquitofish predation may be a critical factor for the survival of pupfish in invaded habitats such as Ash Meadows.