Fifty years later: trophic ecology and niche overlap of a native and non-indigenous fish species in the western basin of
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ORIGINAL PAPER
Fifty years later: trophic ecology and niche overlap of a native and non-indigenous fish species in the western basin of Lake Erie Matthew M. Guzzo • G. Douglas Haffner • Nicholas D. Legler • Scott A. Rush • Aaron T. Fisk
Received: 17 July 2011 / Accepted: 29 December 2012 Ó Springer Science+Business Media Dordrecht 2013
Abstract Since the introduction of white perch (Morone americana) into Lake Erie over 50 years ago, the population size of native yellow perch (Perca flavescens) has decreased up to 79 % and significant changes to the ecosystem have occurred. We examined long-term population estimates and used stable isotopes of carbon (d13C) and nitrogen (d15N) paired
Present Address: N. D. Legler Bureau of Fisheries Management, Wisconsin Department of Natural Resources, 110 S Neenah Avenue, Sturgeon Bay, WI 54235, USA
with stomach content analysis to quantify the trophic ecology and niche overlap of adult yellow perch and white perch in the western basin of Lake Erie. We found that changes in yellow perch abundance since 1979 appeared to be better correlated with changes in fishery exploitation rates than with food competition effects from white perch. At the time of this study, yellow perch were found to have higher d13C values, indicating greater utilization of benthic food resources than white perch, and white perch occupied higher trophic positions based on d15N. The diets of both species varied spatially and seasonally based on stable isotopes and stomach contents, likely driven by changes in prey abundance. Comparison of niche widths using stable isotope population metrics and Schoener diet similarity index suggested a low to moderate degree of niche overlap between species. Isotopic niches of white perch were generally larger than those of yellow perch demonstrating broader resource utilization by this non-indigenous species. We submit that isotopic niche overlap comparisons are more appropriate for studies seeking to understand interactions among populations over course temporal scales, while diet overlap indices, such as the Schoener index provide a means to study fine-scale interactions such as ontogenetic and seasonal diet shifts.
Present Address: S. A. Rush Department of Wildlife, Fisheries and Aquaculture, Mississippi State University, Mississippi State, MS 39762, USA
Keywords Yellow perch White perch Stomach content analysis Diet Stable isotopes Laurentian Great Lakes Niche width Food web Population metrics
M. M. Guzzo G. D. Haffner N. D. Legler S. A. Rush A. T. Fisk (&) Great Lakes Institute for Environmental Research, University of Windsor, 401 Sunset Avenue, Windsor, ON N9B 3P4, Canada e-mail: [email protected] Present Address: M. M. Guzzo Department of Biological Sciences, University of Manitoba, 50 Sifton Road, Winnipeg, MB R3T 2N2, Canada
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Introduction The spread of non-indigenous species (NIS) to new ecosystems is becoming increasingly common in many regions of our planet (Vitousek et al. 1997; Mack et al. 2000). The maj
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