Research on sablefish () suggests that limited capacity to increase heart function leaves hypoxic fish susceptible to heat waves.

Studies of heart function and metabolism have been used to predict the impact of global warming on fish survival and distribution, and their susceptibility to acute and chronic temperature increases. Yet, despite the fact that hypoxia and high temperatures often co-occur, only one study has examined the effects of hypoxia on fish thermal tolerance, and the consequences of hypoxia for fish cardiac responses to acute warming have not been investigated. We report that sablefish () did not increase heart rate or cardiac output when warmed while hypoxic, and that this response was associated with reductions in maximum O consumption and thermal tolerance (CT) of 66% and approximately 3°C, respectively.