Advancing drone research as part of the world’s longest-running dolphin research project
In May 2022, Research Assistant Kyleigh Fertitta and I (PhD Candidate Fabien Vivier) were invited by the Sarasota Dolphin Research Program (SDRP) operated by the Chicago Zoological Society, to help advance drone research in delphinids. This program, led by Dr. Randall Wells, is the world’s longest-running study of a wild dolphin population, focusing on resident bottlenose dolphins (Tursiops truncatus), inhabiting Sarasota Bay, Florida. Since 1970, the SDRP has been studying the biology, ecology, behavior, health, anthropogenic interactions, life history, reproductive success, and genetics of this dolphin population. Periodically, with the help of >100 researchers, nonprofit organizations, government agencies, veterinarians, students, and zoological personnel, the SRDP leads a one-week Sarasota Bay Dolphin Health Assessment Project, aiming at catching and releasing a few individuals from the local population to assess their health in-situ. As part of the project, ultra-sound readings for pregnancy are conducted, morphometric measurements are collected (e.g., weight, length, girth), together with blood and tissue samples to evaluate the overall health of the animals. Once measurements and samples are collected, animals are released into their environment, unharmed and rapidly resuming their activities. To date, ~53% of the dolphins seen most frequently in the area have been sampled at least once, and many others have been observed since birth and/or sampled via biopsy darting, resulting in information on the sex, age and reproductive history of most of the local individuals.
During the week of the Health Assessment Project and the following week, the MMRP was invited to remotely assess the health and pregnancy status of individual dolphins via the use of Unoccupied Aerial System (UAS, or drones)- photogrammetry. The role of the MMRP was to:
1) Collect aerial videos of individual dolphins, that were examined during the temporary captures, to estimate their total body length and body condition. Morphometric estimates, obtained via UAS-photogrammetry, will be directly compared to the hands-on measurements collected on the individuals. During the subsequent week of the project, videos of free-swimming dolphins were collected, and morphometric estimates will be compared to the long-term database.
2) Estimate the age of individual dolphins based on their length – estimated via UAS-photogrammetry (learn more about this method here). This will allow us to quantify the demographic structure (i.e., proportion of calves, juveniles, and adults) of the population, and compare to the one determined through years of research.
3) Assess the pregnancy status of the females in the population. This method will help determining what stages into the pregnancy can be detected via UAS-photogrammetry. Ultimately, understanding the proportion of pregnant females within a population will help infer reproductive rates and better predict the sustainability of the population over the years.
4) Document scars, lesions, evidence of previous entanglements and boat strikes on the dolphins living in Sarasota Bay.
During the first week of the field work, five individuals were examined as part of the Health Assessment Project, including a full-term pregnant dolphin. This female was resighted one week later with her newborn. The ability to conduct research on this animal provided highly valuable information on testing the feasibility of detecting pregnancy in free-ranging dolphins. During the second week of the field work, 57 additional dolphins were sampled with the drone. Mornings were spent on the boat searching for dolphins to measure via UAS-photogrammetry. In the afternoons, measured animals were identified from images through dorsal fin photo-identification, and linked to time stamps on drone recordings. Knowing the identity of these individuals will allow us to look back into the SDRP long-term database and access their true length, age, and sex. From the drone videos, the length, and the age-class (i.e., calf, juvenile, or adult) will be estimated and compared to the long-term records. Additionally, the stage of pregnancy will be determined for the females that may have been pregnant during the sampling week. In the next few months, any female who gives birth will be cross-matched with the females drone-sampled in May. By encountering females and newborns, the approximate date of birth for the calves will be established, allowing us to back-calculate the months into the pregnancy at the time of the aerial sampling. For bottlenose dolphins, the gestation period is about 12.5 months. This information will help us understand the minimal stage into the pregnancy detectable using drones.
Collaborating with the SDRP was a once-in-a-lifetime opportunity that I’ll never forget. Traveling outside the state for research was unfamiliar, but extremely rewarding. Once introductory meetings began, on our second day upon arrival, it was very apparent how much there was to gain from fellow researchers in the room. With graduate school currently on my mind, I felt fortunate for the opportunity to learn about the experiences and accomplishments of over one hundred established scientists. I received insight into the academia world from masters and PhD students at the University of St. Andrews and Duke University – two schools I had been eager to learn more about. They elaborated upon their past, current, and future endeavors, covering research topics like acoustics, biopsies, spatiotemporal patterns, behavioral analysis, and photo-Identification for underrepresented populations. I was offered advice on expectations for graduate school and funding options and listened to personal accounts of the application process. The first week I saw progressive science constructed in real time by distinguished scientists I’ve only read about, which felt like a backstage VIP pass!
I particularly enjoyed seeing tag deployments, which helped me to understand new technology in the field. Some tags recorded acoustics and movement like the DTAG, while others recorded electroencephalography (EEG) signals and movement. I also acquired insight into different sectors of marine science such as nonprofit organizations, government agencies, and private companies. I found it helpful to gain a sense for what jobs the industry has outside of academia, considering my previous experiences have only pertained to such. Some scientists I spoke to in this sector were members of the Marine Mammal Commission, Brookfield Zoo, Dolphin Quest, and US Fish and Wildlife Service. Speaking with these people not only opened my eyes to the duties of their professions, but also allowed me to acknowledge different types of research projects their organizations fund. They shared their journey in the field and obstacles and sacrifices they faced leading to their current positions. Working with SDRP was an entirely different experience than working in Hawaii. The knowledge they have about the local population of dolphins is astounding. Members of the project can spot, track, photograph, and identify dolphins, all while driving the research vessel. They knew the area extremely well, predicting where dolphins would most likely be or if manatees are likely nearby. I learned an immense amount about science, fieldwork, academia, prospective jobs, and projects around the world from this trip and I couldn’t be more grateful to be afforded the opportunity to participate.
Not only was this project enriching on the professional level, but also on the personal level. First, it was a wonderful experience to be part of his large team of people sharing the same passion for the animals and their conservation. Secondly, we were able to meet and connect with wonderful personalities and peers in the field of dolphin conservation research. Contributing to this effort allowed us to observe colleagues conduct their research. Overall, this experience allowed us to expand our knowledge of sampling techniques, large-team operations and engage and meet with colleagues from around the world.
We thank Dolphin Quest, the Dolphin Biology Research Institute, and the Chicago Zoological Society for their financial and in-kind support. We thank Randall Wells for making this project happen and for his logistical support since 2020. Finally, we would like to thank our boat captain Jonathan Crossman for helping us in the field.