Steroid hormone profiles and body conditions of migrating male humpback whales (Megaptera novaeangliae)

•8 reproductive and adrenal steroid hormones were quantified in parallel with adiposity.•Concentrations of most steroid hormones decreased through the reproductive season.•Some hormone-hormone and hormone-adiposity correlations varied seasonally.•Blubber testosterone was correlated to adiposity during the late breeding season.•Blubber testosterone may not reflect fertility at all times in male humpback whales.