Dear Colleagues, My co-authors and I are pleased to share an Open Access Publication in Endangered Species Research entitled "Application of epigenetics to understand the demography of the Lahille’s bottlenose dolphin Tursiops truncatus gephyreus”. ABSTRACT: Estimation of age in wild cetaceans is pivotal for effective conservation, enabling insight into population demographics and long-term viability. Handling cetaceans can be challenging; therefore, developing remote sampling tools to assess age is critical. Epigenetics, specifically DNA methylation, provides an opportunity to develop a remote sampling diagnostic aging tool using DNA extracted from skin biopsy samples. DNA methylation is the addition of methyl groups to cytosine-phosphate-guanine (CpG) sites, and the degree of methylation at a subset of sites has been shown to be correlated with aging (among other biological processes). The degree of methylation can be used to provide chronological age estimates using models called epigenetic clocks. We applied an epigenetic clock previously trained on 358 skin samples from bottlenose dolphins Tursiops spp. from southeastern USA to Lahille’s bottlenose dolphin Tursiops truncatus gephyreus (Ttg), a vulnerable South American cetacean. With less than 600 individuals remaining and ~360 females capable of reproducing, local populations are vulnerable to extinction. Remote biopsy skin samples were collected from 51 Ttg from the Patos Lagoon Estuary and adjacent coastal waters in Southern Brazil to enable DNA extraction, age estimation, and sex determination. The applied Tursiops epigenetic clock model predicted ages ranging from 1 to 45 yr. DNA methylation analysis also facilitated sex identification, confirming 22 females and 29 males. Knowledge of a population’s age and sex structure can inform survival prediction, reproductive capacity, and, subsequently, population recovery, which is of particular importance in the conservation and management of small, isolated, and endangered populations. Barratclough A, Genoves RC, Schwacke L, Fruet P, Tatsch AC, Himes Boor GK, Secchi ER, Gomez FM, Smith CR (2025) Application of epigenetics to understand the demography of the Lahille’s bottlenose dolphin Tursiops truncatus gephyreus. Endang Species Res 58:137-146 https://doi.org/10.3354/esr01441 Thanks so much for your interest and I’d be happy to answer any questions. Best Wishes, Ashley Ashley Barratclough BVetMed, MSc WAH, MS, PhD, MRCVS Conservation Medicine Veterinarian National Marine Mammal Foundation 2240 Shelter Island Drive, San Diego, CA 
