Tuesday, July 24, 2012
Bottlenose dolphins in the northern Gulf of Mexico were hit by a triple whammy of events, leading to an unusually high death rate in early 2011, a paper published in PLoS ONE suggests. Between January and April 2011, 186 bottlenose dolphins (Tursiops truncatus) washed ashore in the northern Gulf of Mexico. Of these, 86 were near-term or newborn, nearly double the historical average. Dolphin deaths are being monitored by an ongoing Unusual Mortality Event (UME) survey, which began in response to high numbers of adult dolphins dying during a period of sustained cold weather in early 2010. The PLoS ONE study suggests that the cold weather was the first of three factors that weakened the dolphin population and contributed to the high death rate. The second was the Deepwater Horizon oil spill that followed in April. And the third was large volumes of cold fresh water from melting snow entering Mobile Bay — an inlet in the Gulf of Mexico — in 2011.