Skin lesion prevalence of estuarine common bottlenose dolphins (Tursiops truncatus) in North Carolina,with comparisons to other east coast study sites

Common bottlenose dolphins (Tursiops truncatus) are sentinels of environmental health. Skin lesions may indicate disease and can be used to infer population health. We estimated the prevalence of skin lesions and identified major lesion types on coastal bottlenose dolphins in Roanoke Sound, North Carolina, over a 3-year period using photo-identification. Boat-based surveys were conducted from April 2012 through October 2014. High quality images of distinctive fins were examined for overall prevalence (P) of any skin lesion (n = 169, P = 0.49, 95% CI = 0.42–0.57). Lesion prevalence estimates varied little between years (2012 P = 0.45, 2013 P = 0.56, 2014 P = 0.52) and most lesions were observed in the spring (P = 0.79, 95% CI: 0.57–0.92). Of six lesion types examined, pale lesions were most common (P = 0.41, 95% CI: 0.30–0.52). Annual lesion prevalence estimates for dolphins in Roanoke Sound were comparable to published estimates for T. truncatus in Charleston, South Carolina, Brunswick, Georgia, and Sarasota, Florida (p ≥ .05), although, seasonal differences in lesion occurrence and type were observed (p < .05). Future studies should examine relationships between lesions and environmental variables and use stranded dolphins to investigate skin lesion etiology.