Increased temperature decreases starvation resiliency in first feeding sablefish (Anoplopoma fimbria)

Waters in the Gulf of Alaska experienced anomalously high temperatures during a recent outbreak of large marine heatwaves (2014-2016 and 2019). These warming events caused shifts in the reproductive phenology of zooplankton and fish species, potentially creating trophic mismatches between the availability of zooplankton prey and the initiation of larval fish feeding. To better understand the implications of warming-induced trophic mismatches on sablefish (Anoplopoma fimbria) starvation resiliency, we reared larval sablefish in the laboratory under two temperature treatments (6°C & 9°C) with two nested feeding treatments (fed & starved). We measured the point of no return, daily larval length, weight, and yolk sac size trajectories, and body morphometrics. Sablefish larvae experienced an 11-day decrease in time to reach point of no return at 9°C, diverging length and weight trajectories between starved and fed larvae at 9°C, smaller yolk sac size at first feeding and earlier depletion at 9°C, and changes in skull morphology between temperature and feeding treatments. These results indicate that sablefish starvation resiliency greatly decreases under anomalous warming in the Gulf of Alaska.