Knowledge of age is extremely important to fully assess a dolphin’s overall health during capture-release health assessments and in post-mortem studies conducted on stranded individuals.
The current method for estimating age in bottlenose dolphins without life-long photo-identification history relies on microscopic examination of growth layers in cross sections of teeth, a laboratory procedure that is both time consuming and costly. Additionally, in live dolphins this requires surgical extraction of a tooth for age determination.
Preliminary research studies have suggested that bone density of the flipper bones could be used as a proxy for age determination in dolphins. Traditional bone density research is conducted in a controlled hospital setting using x-ray based technology that is not compatible for use in open water field settings on live animals and presents regulatory issues for widespread use in stranding response laboratories.
Through a partnership with CyberLogic, Inc., a research and development company based in New York City, a prototype has been developed and tested that uses ultrasound to estimate bone density. The ultrasound-based technology is a safe, reliable alternative to traditional x-ray based bone density techniques and will allow researchers to estimate bone density in live bottlenose dolphins during future health assessment projects, potentially providing a completely non-invasive, real-time approach to estimate age without the need for surgical tooth extraction.
In order for this technology to be validated, a comprehensive baseline of bottlenose dolphin bone density values is being constructed using specimens archived in Mote Marine Laboratory’s Ruth DeLynn Cetacean Osteological Collection and the Coastal Marine Mammal Strandings Assessment Program at the National Ocean Service laboratory in Charleston, South Carolina. This research project is a collaborative effort with the Sarasota Dolphin Research Program, Mote Marine Laboratory, National Marine Mammal Foundation, CyberLogic Inc., National Ocean Service, and Portland State University. Financial support has been provided by the National Science Foundation – Small Business Innovation and Research Program, Association of Zoos and Aquariums – Conservation Endowment Fund, Disney Worldwide Conservation Fund, Greenville Zoo – Conservation Fund, and the American Military University.
This article was published on page 28 in the January 2014 Nicks n Notches.