Monreal-Pawlowsky, T., Carbajal, A., Tallo-Parra, O. et al. 2017. Daily salivary cortisol levels in response to stress factors in captive common bottlenose dolphins (Tursiops truncatus): A potential welfare indicator. Veterinary Record 180(24), 593.

Dolphins in a captive setting can be occasionally subjected to a variety of potentially stressful situations. The stress response comprises a variety of biological reactions to internal or external stimuli elicited when an individual perceives (real or not) a threat to its homoeostasis. The objective of the present study was to assess the acute stress response to anthropogenic stressors in a group of common bottlenose dolphins (Tursiops truncatus). The study was conducted on five adult bottlenose dolphins. During day when construction works were carried out, all five dolphins showed increased salivary cortisol concentrations (p=0.0004); this was more evident in the breeding male who showed a 300-fold increase of cortisol level in the afternoon (3.119 ng cortisol/ml saliva; p=0.004). The assay detected an acute increase in salivary cortisol induced by vibrations and noise in the dolphinarium. The EIA kit tested in the present study is suitable for cortisol determination in bottlenose dolphin saliva since validation tests showed a good repeatability and reliability of cortisol concentrations. Salivary cortisol measurements obtained four different times during a whole day displayed variations similar to that previously established for plasma cortisol. The assay also detected an acute increase in salivary cortisol induced by vibrations and noise in the dolphin facilities.