Daniel L. Yule Thomas R. Hrabik Michael E. Sierszen Edmund J. Isaac Jason D. Stockwell 2014 <p>1. We hypothesised that the autumn spawning migration of Lake Superior cisco (<i>Coregonus artedi</i>) provides a resource subsidy, in the form of energy-rich cisco eggs, from the offshore pelagic to the nearshore benthic community over winter, when alternate prey production is likely to be low.</p> <br/> <p>2. We tested this hypothesis using fish and macroinvertebrate surveys, fish population demographics, diet and stable isotope analyses, and bioenergetics modelling.</p> <br/> <p>3. The benthic, congeneric lake whitefish (<i>C. clupeaformis</i>) was a clear beneficiary of cisco spawning. Cisco eggs represented 16% of lake whitefish annual consumption in terms of biomass, but 34% of energy (because of their high energy density: >10 kJ g wet mass⁻¹). Stable isotope analyses were consistent with these results and suggest that other nearshore fish species may also rely on cisco eggs.</p> <br/> <p>4. The lipid content of lake whitefish liver almost doubled from 26 to 49% between November and March, while that of muscle increased from 14 to 26% over the same period, suggesting lake whitefish were building, rather than depleting, lipid reserves during winter.</p> <br/> <p>5. In the other Laurentian Great Lakes, where cisco populations remain very low and rehabilitation efforts are underway, the offshore-to-nearshore ecological link apparent in Lake Superior has been replaced by non-native planktivorous species. These non-native species spawn in spring have smaller eggs and shorter incubation periods. The rehabilitation of cisco in these systems should reinstate the onshore subsidy as it has in Lake Superior.</p> application/pdf 10.1111/fwb.12340 en Wiley Habitat coupling in a large lake system: delivery of an energy subsidy by an offshore planktivore to the nearshore zone of Lake Superior article