• bottlenose dolphin;
  • Tursiops truncatus ;
  • photo-id;
  • reproduction;
  • seasonality;
  • strandings


Reproductive seasonality of common bottlenose dolphins (Tursiops truncatus) can be affected by numerous ecological and behavioral factors. In 2009, stock boundaries were revised to recognize a Charleston Estuarine System Stock (CESS) of bottlenose dolphins in Charleston, South Carolina. The CESS is a well-studied population with long-term data collected from photo-identification and stranding studies. From 2004 to 2008, a systematic mark-recapture photo-identification study was conducted in the Charleston Estuary to estimate population size of the CESS. Sightings data from this photo-identification study coupled with strandings data (1993–2008) were analyzed to determine the reproductive seasonality of this local population. Both neonate sightings and strandings depicted a primary season of reproduction in the spring into early summer with a small peak in neonate sightings in early autumn, and were significantly different from circular uniform and Von Mises distributions (strandings: < 0.01, = 2.8644; sightings: < 0.01, = 3.2302). This study increases the knowledge of seasonal reproductive patterns of estuarine stocks of bottlenose dolphin stocks in the southeastern United States. The results will also help wildlife managers detect unusual neonate mortality events, and provide information about critical habitat relevant for evaluating and mitigating coastal development projects.