Abundance of the Common Bottlenose Dolphin, Tursiops truncatus (Montagu, 1821) (Mammalia: Artiodactyla: Delphinidae) off the South and West Coasts of Puerto Rico
The abundance of the common bottlenose dolphin, Tursiops truncatus (Montagu, 1821) was investigated by mark recapture methods using photographic surveys on the south and west coasts of Puerto Rico from 2013 to 2015. The number of individuals having distinctive marks was 62, representing 46.5% of dolphins observed. Additionally, two dorsal fins were matched with photos taken during a study in 2000, making this the first report of long term resightings in Puerto Rico. The abundance estimate for the south and west coast of Puerto Rico was of 127 dolphins. This represents a statistically significant, 60% decrease from the reported estimate back in 2001. It is unclear whether this decline is due to emigration, mortality, or a combination of the two. Management should prioritize further studies on the health of this population and the potential factors contributing to the decline, such as overfishing or excessive boat traffic.