Using unoccupied aerial system (UAS), or drone photography, researchers from the University of Hawaiʻi at Mānoa School of Ocean and Earth Science and Technology (SOEST) are now able to determine the age-structure of free-ranging dolphin groups. This work will aid monitoring the health of dolphin populations and inform timely conservation efforts. The findings of the study that developed and applied this new technique were published in Ecology and Evolution.
When dolphins come to the surface to breathe, they expose their blowhole and dorsal fin. By measuring the distance between the two, researchers can estimate their total body length. Since total length is related to age, the international team of researchers, led by scientists at the Hawaiʻi Institute of Marine Biology (HIMB) in SOEST, developed a technique of inferring age based on length for each measured dolphin within a group.
“This method can help us quantify the age-structure of free-ranging populations,” said Fabien Vivier, lead author of the study and marine biology doctoral candidate in the Marine Mammal Research Program at HIMB. “Healthy dolphin populations usually contain a certain proportion of newborn, immature, and mature animals, while deviances from this distribution may be interpreted as a population growth or decline.”
Read more at University of Hawaiʻi at Mānoa
Photo credit: Marine Mammal Research Program. NOAA Fisheries Permit #21476