Larval lake whitefish feeding success in Lake Huron’s Fishing Islands and the implications for recruitment

Lake whitefish (Coregonus clupeaformis) are experiencing declining recruitment across several regions of the Laurentian Great Lakes possibly due to low availability of zooplankton prey for the larval life stage as a consequence of invasive dreissenid mussels. The ability for larval fish to feed successfully is important for their growth and survival and thus can impact recruitment to later life stages. Here, we examined feeding success of larval lake whitefish to better understand factors limiting recruitment of this commercially harvested fish in Lake Huron. We found that feeding success varied annually and was positively related to larval body condition and survival but negatively related to the density of larval cisco, a closely related coregonine. The early spring period likely represents a critical bottleneck as there are fewer prey and more competitors when larval lake whitefish are smaller and more vulnerable to starvation. Together, our findings suggest that the ability of larval lake whitefish to feed successfully influences their survival and that annual variability in feeding success is driven by density-dependent and independent mechanisms affecting food availability.