Prevalence of epidermal conditions in common bottlenose dolphins (Tursiops truncatus) in the Gulf of Ambracia, western Greece

• Bottlenose dolphins' epidermal condition was examined based on photo-id data.
• One out of every three dolphins in Ambracia (Greece) suffers from some skin condition.
• Five known and one new (and particularly severe) skin conditions were reported.
• The newly described condition seems to be stable or increase in severity over time.
• Various anthropogenic factors may be affecting the epidermal integrity of dolphins.

Bottlenose dolphins (Tursiops truncatus) of the Gulf of Ambracia are exposed to numerous growing anthropogenic impacts, rendering them more prone to cutaneous changes. The prevalence of skin conditions in this resident population was evaluated based on photo-identification. Five skin lesions previously described in other studies were considered, namely dark-fringed spots, white-fringed spots, orange patch, tattoo-like and white fin-fringe, in addition to a new particularly severe condition named as “white dots” (WD). A 37% prevalence of epidermal lesions was detected on a total of 153 dolphins. The newly identified WD was the skin condition most frequently observed (45%) in the area, showing considerable differences on its severity between individuals. From 29 dolphins affected by WD in 2012, two were severely affected throughout their 10-year photo-id records and all of them either worsened over the years, or maintained their WD condition. No cases were found in which WD resolved over time. The increasingly degraded conditions of the Gulf of Ambracia may be influencing their epidermal integrity or causing them physiological stress. The epidermal conditions here reported, in some cases very conspicuous and relatively easy to monitor over the years, might act as indicators of environmental burden.