Data for: Sex-specific differences in swimming, aerobic metabolism, and recovery from exercise in adult coho salmon (Oncorhynchus kisutch) across ecologically relevant temperatures

Adult female Pacific salmon can have highermigrationmortality rates thanmales, particularly at warm temperatures. However, the mechanisms underlying this phenomenon remain a mystery. Given the importance of swimming energetics on fitness, we measured critical swim speed, swimming metabolism, cost of transport, aerobic scope (absolute and factorial) and exercise recovery in adult female and male coho salmon (Oncorhynchus kisutch) held for 2 days at 3 environmentally relevant temperatures (9oC, 14oC, 18oC) in fresh water. Critical swimming performance (Ucrit) was equivalent between sexes and maximal at 14oC. Absolute aerobic scope was sex- and temperature-independent, whereas factorial aerobic scope decreased with increasing temperature in both sexes. The full cost of recovery from exhaustive exercise (excess post-exercise oxygen consumption) was higher in males compared to females. Immediately following exhaustive exercise (i.e. 1 h), recovery was impaired at 18oC for both sexes. At an intermediate time scale (i.e. 5 h), recovery in males was compromised at 14oC and 18oC compared to females. Overall, swimming, aerobic metabolism and recovery energetics do not appear to explain the phenomenon of increased mortality rates in female coho salmon. However, our results suggest that warming temperatures compromise recovery following exhaustive exercise in both male and female salmon, which may delay migration progression and could contribute to en route mortality.

Methods
All methods are described in the original published article and its supplemental material.