Characterizing growth patterns of bottlenose dolphins (Tursiops truncatus) in Sarasota Bay

Growth patterns of specific body structures provide insight into the physiological and developmental processes underlying their function. Sampling individuals in the marine environment can be challengingdue to the limited ability to collect hands-on measurements and brief periods of observation through other methods (e.g., photogrammetry). The Sarasota Bay resident bottlenose dolphin (Tursiops truncatus) community has been the subject of several morphological studies, due to the unique sampling environment of the bay, with over 50 years of morphometric data collection. Other studies have documented sexual dimorphism for some morphological features within this dolphin community; however, most studies have focused on maximum length and girth, and few have considered variation in growth at the individual level. This study developed growth models using repeated measurements of individuals over their lifetimes to examine growth patterns and potential sexual dimorphism of thirteen less-studied body traits of Sarasota Bay bottlenose dolphins. Measurements were collected during catch-and-release projects (n = 218) and necropsies (n = 59) from 1984 to 2024. Gompertz and Richards growth curves were used to model the measurements, and growth parameters were bootstrapped with 95% confidence intervals to determine whether sexual dimorphism was present for each measurement. We determined that sexual dimorphism existed for all measurements assessed, verifying that males typically grew larger than females and females typically reached their maximum size at a younger age than males. Variation between dolphins and within-dolphin variation were also present among all morphological measurements. Within-individual variation and between-individual variation were relatively low (< 3%) for dorsal fin height. However, dorsal fin length was the most variable measurement. The growth patterns observed with the dorsal fin could be reflective of its functional role for thermoregulation and hydrodynamic stability. Understanding growth of individual morphological features can help assess how injury may impact the development or function of certain body traits, which may have long-term health implications for individual animals. This abstract was presented at the American Physiology Summit 2026 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.