Bottlenose dolphins exhibit unique dorsal fin shapes that have become an important morphological feature to use for individual identification in the study of population abundance, movements and health. A range of naturally occurring nicks, notches and rake marks / bite marks by conspecifics can be found on the body and dorsal fin. In one extreme incident an individual resident Indo-pacific bottlenose dolphin (Tursiops aduncus) of Jervis Bay NSW displayed the impact of large preseason cuts and abrasions from bites to the upper body and dorsal fin by a predator, most likely a large shark. The evolution of dorsal fin morphology in marine species is an essential area of study, particularly following extreme incidents that can lead to significant anatomical changes. Researchers use the technique known as mark-recapture, photo-identification of individual animals over time, within a local population or area, allowing for life histories to be documented and tracked with accuracy. This presentation shows the extreme side of change in dorsal fin characteristics on an individual and the use of photo-identification as a tool to aid in revealing the identity of a known individual following a sudden environmental impact and the dynamics of marine populations and their morphological changes over time.