Post-settlement abundance, condition, and survival in a climate-stressed population of Pacific cod

The Pacific cod (Gadus macrocephalus) fishery recently collapsed in the Gulf of Alaska after a series marine heatwaves that began 2014. To gauge likelihood population recovery following these extreme warming events, we investigate potential thermal stress on age-0 cohorts through comprehensive analysis juvenile abundance, condition, growth, and survival data collected from 15 years beach seine surveys. Abundance was strongly negatively related to ocean temperature during egg larval phase (winter/spring), but were larger early summer warm winter/spring temperatures. Body condition indices suggest summers may improve energetic reserves prior first winter; however, there no effect post-settlement growth or survival. Spatial differences not detected, density-dependent effects either weak positive. While positive increased temperatures benefit overwintering survival, they cannot compensate for high pre-settlement mortality We conclude critical bottleneck abundance occurs pre-settlement.