Researchers have found severe to profound hearing loss in 57 percent of the bottlenose dolphins and 36 percent of the rough-toothed dolphins studied after the animals stranded. Results of this study were published in the November 3, 2010 edition of the journal PLoS One.
The study’s authors included our SDRP colleagues Dr. David Mann and Dr. Mandy Hill-Cook who have been studying the hearing of SDRP dolphins during health assessments. SDRP Director Dr. Randy Wells as another of the co-authors.
During the study, a team of 16 scientists from marine science colleges and institutes across the United States and the Caribbean examined 36 dolphins and toothed whales in Florida and at a number of aquariums and rehabilitation centers. The animals had been found stranded or entangled in fishing gear between 2004 to 2009, and ranged in age from calves to adults, including one dolphin believed to have reached a ripe old age, given his lack of teeth.
Given that these species rely on echolocation for orientation and feeding, the researchers believe that hearing loss could play a significant role in some strandings, said Dr. David Mann, a USF biological oceanographer and the paper’s lead author. The finding might also provide good cause for veterinary experts, scientists and resource managers to rethink the rehabilitation and release of dolphins given the role hearing loss might play in their trauma.