Suresh Sethi Lars G. Rudstam Jeremy P. Holden Michael J. Connerton Dimitry Gorsky Curtis T. Karboski Marc Chalupnicki Nicholas M. Sard Edward F. Roseman Scott E. Prindle Matthew J. Sanderson Thomas M. Evans Amanda Cooper Daren J. Reinhart Cameron David Brian Weidel Taylor A. Brown 2022 <p><span>Coregonine fishes are important to Laurentian Great Lakes food webs and fisheries and are central to basin-wide conservation initiatives. In Lake Ontario, binational management objectives include conserving and restoring spawning stocks of cisco (</span><span><i>Coregonus</i><i>&nbsp;artedi</i></span><span>) and&nbsp;lake whitefish&nbsp;(</span><i>C. clupeaformis</i><span>), but the spatial extent of contemporary coregonine spawning habitat and the environmental factors regulating early life success are not well characterized. In Spring 2018, we conducted a binational&nbsp;ichthyoplankton&nbsp;assessment to describe the spatial extent of coregonine spawning habitat across Lake Ontario. We then quantified the relative importance of a suite of biophysical variables hypothesized to influence coregonine early life success using generalized additive mixed models and multimodel inference. Between April 10 and May 14, we conducted 1,092&nbsp;ichthyoplankton&nbsp;tows and captured 2,350+ coregonine larvae across 17 sampling areas, predominantly within embayments. Although 95% of catches were in the eastern basin, coregonine larvae were also found in historical south shore spawning areas. Most coregonine larvae were cisco; &lt;6% were lake whitefish. Observed catches of both species across sampling areas were strongly and similarly associated with ice cover duration, but the importance of site-specific characteristics varied, such as distance to shore and site depth for cisco and lake whitefish, respectively. These results suggest that regional-scale climatic drivers and local environmental habitat characteristics interact to regulate early life stage success. Furthermore, strong regional and cross-species variation in larval distributions emphasize the importance of lake-wide assessments for monitoring both the current eastern basin populations and potential expansions into western Lake Ontario habitats.</span></p> application/pdf 10.1016/j.jglr.2021.07.009 en Elsevier Contemporary spatial extent and environmental drivers of larval coregonine distributions across Lake Ontario article