All dolphin photography taken under MMPA Permit #21938-03.
May not be used for commercial purposes.
 Dam (DMWE) in the freshwater Withlacoochee River. By Carrie Cramer, Field Assistant We have reached the halfway point of the 2024 field season, so we have lots of updates to share! Unfortunately, Hurricane Debby made landfall on August 5th in Florida’s Big Bend region, near Cedar Key and our other field sites, which range from Crystal River to the Suwannee River. We will resume our surveys as soon as it is safe to get back on the water. Over the next few weeks, we will be researching whether there are any observable effects of the storm on the dolphin population. Before the hurricane, we were able to complete 23 days of research on the water. We have spent the other days hard at work in the lab processing photo-ID, acoustic, and drone and Insta360 video data. So far, we have conducted 83 “sightings,” which are behavioral and photo-ID surveys completed every time we encounter one or more dolphins. We have also completed 19 focal-follow surveys, during which we follow a specific dolphin to collect more in-depth data on interesting behaviors, such as mom-calf communication or driver-barrier foraging. We have identified 169 unique dolphins in these sightings, with many yet to be identified! Similarly to last year, we have encountered quite a few large groups of socializing dolphins. The largest group we have seen this year was observed right off the Cedar Key boat launch, an area where dolphins often congregate to socialize for unknown reasons. This sighting contained at least 53 dolphins! Our first field day was spent on the unusual task of assisting University of Florida Marine Animal Rescue (UF-MAR) with monitoring a dolphin that was sighted repeatedly this summer in the Withlacoochee River and Cross Florida Barge Canal. It was often seen near the Lake Rousseau Dam, which is approximately 12 km from the ocean! Although bottlenose dolphins (Tursiops truncatus) can tolerate exposure to fresh water for brief periods of time, prolonged exposure can lead to skin lesions and life-threatening physiological health issues (Ewing et al. 2017). Visually monitoring this dolphin for lesions can help determine when it begins facing serious health risks due to the freshwater exposure. While surveying this dolphin, we observed it traveling in the river and foraging at the Lake Rousseau Dam, perhaps taking advantage of the barrier to catch fish. After analyzing the survey photos, we determined that it was not a known individual in our catalog and named it Dam (DMWE). We were pleased to see Dam again on July 27th in saltwater, indicating that it is able to find its way out of the river. We have had lots of exciting calf sightings throughout this field season! We identified and named four young-of-the-year (YOYs), which are calves born this year. At least nine additional YOYs have been sighted, but they have not been named yet. To ensure that we correctly identify their mothers, we wait to name calves until we have seen them on at least three separate days. We have also re-sighted seven of the eleven calves added to the catalog in 2023 and eleven of the twenty-seven calves added in 2022. It is always exciting to see that a calf has survived its first few years of life, as they are particularly vulnerable during this time. We were especially thrilled to see one-year-old D’it (DTNL), calf of Nail (NLCT), who became entangled in aquaculture netting last year. In August 2023, CKDP participated in the successful disentanglement of D’it in collaboration with UF-MAR and the Sarasota Dolphin Research Program. Check out this blog post for more information about this process. We’re happy to report that D’it’s scars caused by the netting appear to have healed remarkably well! Stay tuned for more information on calves in the upcoming weeks.  D’it’s (DTNL) scars two weeks after disentanglement from aquaculture netting in August 2023.  D’it (DTNL) in July 2024, with small scars visible behind the blowhole.  Fling (FGWB), a frequent participant in driver-barrier foraging, leaping while socializing with other dolphins. Despite the challenges brought by Hurricane Debby, we are pleased with the amount of data we have collected so far during this field season. Our field manager, Jolinde, is looking forward to analyzing the concurrent acoustic and drone video data that we have collected for her PhD research on turn-taking. Check out this blog post for more info on her project. We have also been lucky to observe driver-barrier foraging many times this year, and have identified several new dolphins who participate in this type of cooperative foraging! We have captured acoustic and drone video data of this, which will allow us to better understand how dolphins communicate and coordinate their actions during driver-barrier foraging events. See this blog post to learn more. We are very excited to see what the rest of the field season will bring!
References Ewing, R. Y., Mase-Guthrie, B., McFee, W., Townsend, F., Manire, C. A., Walsh, M., Borkowski, R., Bossart, G. D., & Schaefer, A. M. (2017). Evaluation of serum for pathophysiological effects of prolonged low salinity water exposure in displaced bottlenose dolphins (Tursiops truncatus). Frontiers in Veterinary Science, 4, 80. https://doi.org/10.3389/fvets.2017.00080
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