ABSTRACT Age determination is essential in ecological and conservation research, particularly for long‐lived species, such as cetaceans. Age data provide insights into life‐history traits and population dynamics. Estimating the period of parturition at a finer temporal resolution allows analyses of birth seasonality, early development, and mother–infant interactions. However, comprehensive age datasets for wild cetaceans remain scarce. This study compiles and presents a dataset for Indo‐Pacific bottlenose dolphins ( Tursiops aduncus ) around Mikura Island, Japan, summarizing (1) the actual and estimated ages (in years) of identified individuals and (2) the estimated periods of parturition of neonates based on long‐term underwater individual identification surveys. Age determination was based primarily on long‐term individual identification surveys initiated in 1994. Two methods were used to estimate the age of individuals with unknown birth years: speckle pattern analysis and epigenetic clock analysis. Age data were available for 85.6% ( n = 268) of all identified individuals in this population ( n = 313). Among these, 172 individuals had known birth years, 117 individuals had estimated ages based on speckle pattern analysis, and 19 individuals had ages estimated using epigenetic analysis. The totals differ slightly due to overlap among methods. Estimated periods of parturition were inferred from the interval between the mother's last solitary sighting and her first sighting with a newborn ( n = 120). The earliest recorded births occurred before March, the latest between late September and early October, and the peak occurred before August. This dataset provides valuable baseline information on age and reproductive timing, supporting future age‐related studies. The Metadata for this abstract is available in MetaCat in JaLTER at https://doi.org/10.20783/DIAS.JLE.93 , and the complete dataset is available at https://doi.org/10.6084/m9.figshare.32395155 .
Yagi et al. (Tue,) studied this question.