Epigenetic characterization of age-structure in a wild bottlenose dolphin population from Naples, FL.

Age constitutes a critical parameter for the study of animal populations, providing information about development, environmental effects, survival, and reproduction. Unfortunately, age estimation is not only challenging in large, mobile and legally protected species, but often involves invasive sampling methods. In our previous work we investigated the association between epigenetic modifications (DNA methylation) and chronological age in small cetaceans to develop and validate the “Bottlenose dolphin Epigenetic Age estimation Tool” (BEAT). This tool improves minimally-invasive age estimation in free-ranging small cetaceans. In the present work, the BEAT is used for the first time to assess the age-structure of a wild population of bottlenose dolphins residing in the coast of Naples, FL. For that purpose, 30 dolphin individuals were sampled using biopsy dart sampling. The obtained samples were preserved in ethanol and subsequently transported to our laboratory, where DNA was extracted and the %DNA methylation at target CpG sites was quantified using pyrosequencing. These results, along with the identification of the sex of the sampled individuals, is discussed on the context of dolphin population conservation and management in the Gulf of Mexico.