Paired measurements of progesterone, testosterone, oestradiol and cortisol in the blubber, serum and respiratory vapour ('blow') of captive bottlenose dolphins (Tursiops spp.). Additional measurement of urea nitrogen (UN), a potential marker of blow dilution, in blow samples for some captive bottlenose dolphins. Several adult males also sampled for semen in order to assess links between testosterone levels and sperm characteristics (concentration, motility). Sampling conducted across several months in year, using both in-water (voluntary) sampling and out-of-water (capture-restraint) procedures). The reproductive state of females was classified at each time point using behavioural indices (e.g. evidence of oestrous behaviours), ultrasonographic examinations (ovarian and uterine) and information on contraceptive schedules. Blow hormone data also presented as hormone ratio values (progesterone:testosterone, progesterone:oestradiol, oestradiol:testosterone, cortisol:progesterone, cortisol:testosterone, cortisol:oestradiol) and expressed relative to urea nitrogen concentration (i.e. ng of hormone per mg of urea nitrogen in sample). Exhalation strength (weak or strong) used as a proxy for blow sample volume.