Ultrasonic bone assessment in Tursiops truncatus a proposed means for monitoring marine ecosystem health

In order to circumvent limitations in traditional radiographic bone density assessment, a custom quantitative ultrasound device and protocols were developed for assessment of live bottlenose dolphins, Tursiops truncatus. In laboratory measurements on disarticulated pectoral flippers collected post-mortem, a strong correlation was established between bone mineral density (BMD) as measured with quantitative ultrasound and X-ray (r=0.93). A primary target skeletal site in the radius of the dolphin pectoral fin was comprehensively defined. BMD distribution patterns throughout the radius were characterized and a single region of interest (ROI) with a high correlation to the density of the overall bone (r=0.98) was selected. Statistical tests demonstrated no statistically significant differences in any subset based on sex, age, total body length, handedness, nutritional status, or geographical affinity, supporting inclusion of all specimens as a normative reference dataset for bone density in bottlenose dolphins. Initial trials to develop clinical protocols and establish ultrasound of bone as truly non-invasive were conducted on captive dolphins. Successful assessments were subsequently conducted to ultrasonically assess BMD in wild dolphins during capture-release health assessments.