Consistent differential resource use by sympatric Lake (Coregonus clupeaformis) and Round Whitefish (Prosopium cylindraceum) in Lake Huron: a multi-time scale isotopic niche analysis.

Lake and Round Whitefish are sympatric benthivores in Lake Huron that are thought to coexist via niche partitioning. However, little is known about long-term resource use and niche overlap across different temporal scales. We used a multi-year (2010-2012) and multi-tissue (liver, muscle, and bone layers) isotopic niche analysis to characterize and compare resource use by Lake and Round Whitefish across several time scales. Lake Whitefish consistently used more diverse, 13C-depleted (mean δ 13C = –21.9‰) and 15N-enriched (mean δ 15N = +9.3‰) resources than Round Whitefish (mean: δ 13C = –18.2‰; δ 15N = +8.3‰). Niche overlap occurred only in liver, representing the spawning period, while niche segregation was highest in juvenile life stages. Individuals of both species made variable resource-shifts among time periods, suggesting that spawning aggregations are comprised of individuals representing a variety of feeding strategies and locations. Our study confirms that differential resource use is an important strategy for these fish as adults, and demonstrates life-long niche partitioning beginning before age 2.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author