Frigid but not fragile: Hypoxia performance and tolerance of polar fishes

The frigid climate of polar regions has given rise to unique adaptations in the fish fauna, some of which may limit their capacity to withstand climate change. The frequency and severity of hypoxic events are increasing worldwide, yet little is known about the hypoxia tolerance of polar fishes. In this review, we compare what is known about hypoxia tolerance between Arctic and Antarctic fishes. We highlight the knowledge and resource gaps needed to improve predictions of the capacity of polar fishes to withstand hypoxic events. Available data suggest that despite their evolution in a frigid environment, polar fishes may be more resilient to hypoxia than expected.