Research Interests

My research interests focus on the conservation of freshwater fishes in Wisconsin and Mexico, the impacts of exotic fishes in freshwater systems, the use of fishes as indicators of environmental quality, and freshwater food webs.

1) Rainbow smelt

In Wisconsin, I am studying different aspects of the impacts of an exotic fish, the rainbow smelt (Osmerus mordax), on the native fauna of lakes in Northern Wisconsin.  Along with colleagues at the Center for Limnology and the University of Minnesota-Duluth, I generated a model to predict their future distribution in lakes in the Great Lakes region.  I am also studying the effect of Osmerus mordax on Wisconsin walleye population.

2) Indices of Biotic Integrity

Human degradation of freshwater systems in Mexico is severe.  I am interested in the development and use of biological monitoring techniques in Mexican freshwater ecosystems. Indices of biotic integrity (IBI) have been developed for a number of freshwater ecosystems in Mexico, but their use in Mexican systems is incipient.  Expansion of their use throughout the country could benefit ongoing efforts to conserve the highly endemic freshwater fish fauna of Mexico.  Data  collected from a number of sampling trips to several rivers in Mexico will be used to modify existing IBIs, and make them applicable to new systems.

3) Food webs

 In Mexico, I am studying changes in the food webs of the Laja River (Guanajuato, Mexico) as a consequence of the invasion of several exotic species.  I am using stable isotope techniques to determine the present state of the trophic web in the Laja and compare it with that of pre-invasion times using museum specimens.  I am developing this project in conjunction with colleagues from the Institute of Biology of the Universidad Nacional Autónoma de México, the Instituto Politécnico Nacional and the Universidad Autónoma de Querétaro, in Mexico.

4) Invasive species in Mexico

In collaboration with colleagues in Mexico and the U.S. I am working in the creation of an extensive basin-specific database of the freshwater fishes of Mexico that will include all known invasive species. This database, which will include environmental attributes of the different basins in the country, will allow for the study of the dispersal of invasive species in the country.