Desiccation Tolerance in a Wild Population of the Invasive Oriental Weatherfish Misgurnus anguillicaudatus in Idaho, USA

Abstract

The oriental weatherfish Misgurnus anguillicaudatus is a nonindigenous, cryptic species for which the currently invaded range spans 13 states in the USA as well as six other countries. Anecdotal evidence suggests that because they are facultative air-breathers, oriental weatherfish can survive in the terrestrial environment and may move across land to colonize new water bodies. Given the lack of empirical research on this subject, we conducted an experiment with oriental weatherfish to determine their longevity under increasingly dry conditions and their tolerance to desiccation. We introduced the fish (obtained from a wild population in Idaho) into a series of tanks and allowed some of the tanks to dry out. Over the course of the experiment, we measured substrate moisture content and temperature in each tank, and we periodically removed some fish to determine changes in mass and to check the status (alive or dead) and viability of the fish. Some individuals survived for over 81 d in desiccated conditions with soil moisture content less than 3%; these fish lost over 25% of their body weight. No mortalities occurred in the control group, which lost no more than 20% of their body weight despite being unfed for nearly 90 d. Our findings add to a growing list of traits indicating that the oriental weatherfish fits the profile of a highly successful invader and therefore should be a species of concern.

Received May 5, 2011; accepted August 26, 2011

ACKNOWLEDGMENTS

We thank Dennis Daw and Jennifer Tabbutt for their support in the field and laboratory. We are also grateful to Idaho Fish and Game personnel at the Eagle Island Hatchery and at the Southwest Regional Office for site locations of incidental catches and for property access that facilitated collection of experimental fish. Finally, we thank Professor Emeritus Jim Long of Boise State University for bringing this fish species to our attention. All field and laboratory procedures were conducted in accordance with Policy Number 5070 of the Institutional Animal Care and Use Committee at Boise State University.