Salinity Affects Wound Healing in Wild Common Bottlenose Dolphins (Tursiops truncatus)

Dolphins are often individually identified by unique naturally-acquired markings. Identification becomes difficult when markings heal, or new scars appear. As salt accelerates wound healing in many organisms, the diminishment of scars on common bottlenose dolphins (Tursiops truncatus) residing in varying natural salinities was determined. South Texas contains the only hypersaline lagoon in the USA, located adjacent to hyposaline waters, with genetically distinct populations of dolphins in the two environments. Photographs of dolphin dorsal fins were collected, and scar stability over time was determined and compared by measuring changes in the relative lengths and surfaces of scars. All scars on dolphins in the hypersaline lagoon completely diminished between three to six years, while scars on dolphins in the hyposaline bay ranged in the amount of fading between three to six years. Data from this case study indicate that high salinity may increase the healing speed of wounds on common bottlenose dolphins compared to low salinity, although a larger sample size is needed for robust statistical comparison. Scar diminishment is an important consideration in determining the temporal reliability of photo identification. KEYWORDS: Bottlenose dolphin; Corpus Christi Bay; healing; hypersaline; Laguna Madre; photo-identification; salinity; scar