Bone density is an indicator of health in many mammals, including humans. During the 2014 and 2015 Sarasota Bay health assessments, the first-ever measurements of bone density in live, free-ranging bottlenose dolphins were performed. Measurements of bone density in dead, beachcast dolphins are straightforward, as skeletal specimens can be collected and analyzed through traditional laboratory methods; however, novel technology and protocols had to be developed in order to include bone density assessments in the overall health evaluation of live dolphins. To date, bone density profiles have been established for 17 dolphins in Sarasota Bay.
In addition to these measurements, bone density values from archived skeletal specimens for nearly 300 dolphins from both Sarasota Bay and coastal South Carolina were recorded to develop the first ever reference dataset for bottlenose dolphin bone density. This reference dataset is being used as a baseline by which to compare bone density values for dolphins in areas where human impacts, such as high levels of contamination, are of great concern. In September 2015, bone density measurements were incorporated as part of the health diagnostics performed in a NOAA bottlenose dolphin capture-release health assessment in the estuarine and coastal waters near Brunswick, GA, where some of the highest PCB concentrations ever recorded for dolphins have been documented. Bone density values for individual dolphins assessed during this project will be compared to Sarasota Bay resident dolphins and the bottlenose dolphin reference dataset to determine whether coastal bottlenose dolphins differ in bone density from estuarine resident dolphins and to examine whether estuarine bottlenose dolphins exposed to high levels of environmental contamination exhibit lower bone density than dolphins from Sarasota Bay.
This article appeared on pages 19-20 in the December 2015 issue of Nicks n Notches.