Growth of young-of-year sablefish (Anoplopoma fimbria) in response to temperature and prey quality: Insights from a life stage specific bioenergetics model

Abstract

The first year is typically a bottleneck for juvenile fishes and survival at this stage can be dictated by environmental conditions affecting growth, such as temperature and food availability. Shifts in environmental conditions—and the resulting effects on growth—are of particular concern for high latitude species, which are experiencing more pronounced impacts of climate change. We measured effects of temperature on growth, consumption, and respiration of young-of-year (YOY) Sablefish (218–289 mm TL; Anoplopoma fimbria) in laboratory trials. Physiological response functions were used to outfit a novel, life stage specific bioenergetics model. Average daily growth rates ranged from 0.82 to 3.42 g d−1 (46.7 to 122 J g−1 d−1), with optimum growth occurring at 12–16 °C and declining substantially outside of this range. We then validated the model by comparing model estimates of growth to known growth rates for a separate cohort of Sablefish reared under controlled conditions. Sensitivity analysis indicated that the consumption-related parameters had the greatest influence on model outputs. As such, consumption parameters should be determined with care. Finally, we used the model to characterize the conditions necessary for wild YOY Sablefish to successfully settle from neustonic to demersal stages by modeling temperature-prey scenarios that reflect the transition from neustonic offshore to demersal nearshore habitats observed over the period from August to October. Our findings suggest that Sablefish in the Gulf of Alaska could thrive under warming ocean conditions given sufficient food, which corroborates reports of high Sablefish recruitment events following a marine heat wave in 2014.