Welcome to Sarasota Bay’s New 2023 Calves!

During our monthly Sarasota Bay dolphin photographic identification surveys, we’ve documented three new calves so far this year! The first, who we told you about last month, was 1654, the fourth calf of 24-year-old Sarasota resident, F165.

More recently, we’ve identified two additional calves. One, 1794, is the fourth calf of 21-year-old F179; the second, 2114, is the offspring of 18-year-old F211, also known as Ginger.

We’ve observed Ginger more than 550 times since her birth in 2005. She is the first calf of F127, Edamommy, who had only one other calf, F264, aka Wasabi. (See what we did there?!) Ginger’s grandmother was FB13, who was first observed by SDRP in 1975, but died in 2009 at age 50.

We actually know Ginger a little bit better than most other Sarasota Bay dolphins — that’s because in December 2008, we helped to recover her when she stranded on Siesta Key Beach, after separating from her mother following the birth of Wasabi.

• You can learn more about her life history, including her stranding and rehabilitation, here.

Ginger, left, and her fourth calf, 2114.

F179 and her fourth calf, 1794.

Notes from the Field and Lab

We’ve spent the last couple of weeks in Barataria Bay, Louisiana, working with 20 organizations to check on the health of the dolphin population there that was badly impacted by the Deepwater Horizon oil spill, and investigating their ability to respond to threats from multiple stressors.

The team, led by the National Marine Mammal Foundation and University of St. Andrews, dealt with challenges from high winds, thunderstorms, a waterspout, record heat, stingrays and stinging jellyfish while examining and tagging 24 dolphins. The final sampling involved removing recreational fishing gear that had badly damaged one dolphin’s dorsal fin. More than 13 years after the largest man-made oil spill in the Gulf’s history, the dolphins around this bay are still feeling the impacts.

• You can learn more about our research findings here.

We’ve also continued to track the four offshore dolphins (two Atlantic spotted, two bottlenose) that we tagged back in May. While three of the dolphins have remained more than about 20 miles offshore of Tampa-Sarasota, one traveled far to the south. On July 1, the bottlenose dolphin nicknamed “Per” was more than 50 miles northwest of Key West. More recent tracks showed him heading north again and today, he is offshore of Sarasota.

This July 1, 2023, map shows the location of the offshore dolphins we tagged in May. The dots furthest south show Per's location off Key West.

This morning's map (July 6, 2023) shows that Per has returned to waters offshore of Sarasota.

Closer to home, SDRP staff were co-authors on two new papers published by colleagues. The papers really highlight the unique natural laboratory we have here in Sarasota Bay and the importance of the long-term data we’ve been gathering over more than five decades.

One study, led by Fabien Vivier of the University of Hawaii, looked at whether Unoccupied Aerial System (UAS) photogrammetry — using photography to estimate size — could help accurately gauge the length of dolphins. Monitoring wild populations is crucial for effective management and conservation, and changes in population size structure (based on lengths) can provide early indications of changes in age structure and, subsequently, the possibility that a population might be in decline.

Because we have such complete data about the dolphins in our study population, researchers can use that information to compare the UAS photogrammetry data collected to determine its accuracy.

The images on the left show a researcher physically measuring the total length of a dolphin. The images on the right were taken using UAS photogrammetry of a stationary and a surfacing dolphin.

Overall, the study showed that 72.5%–93% of the individuals were correctly classified within two years of their actual age-class — meaning that UAS photogrammetry can be a non-invasive, inexpensive and effective method to estimate the length and age-class of free-swimming dolphins, and that we have another tool in our toolbox to monitor wild populations for changes.

• Study Citation: Vivier, F., R. S. Wells, M. C. Hill, K. M. Yano, A. L. Bradford, E. M. Leunissen, A. Pacini, C. G. Booth, J. Rocho-Levine, J. J. Currie, P. T. Patton, L. Bejder. 2023. Quantifying the age structure of free-ranging delphinid populations: Testing the accuracy of Unoccupied Aerial System photogrammetry. Ecology and Evolution. 13:e10082. Study link.

The second recently published study that relied on our long-term data, led by Laela Sayigh of Woods Hole Oceanographic Institution, focused on how dolphin mothers communicate with their calves. The study, published in The Proceedings of the National Academy of Sciences, shows that dolphin moms change their signature whistles when they communicate with their calves, similar to the way human caregivers change their pitch and tone when talking to babies or young children.

Known as “motherese” or “parentese,” this speech pattern promotes attention, bonding and language acquisition and has been documented across nearly all human cultures and languages. It has also been documented elsewhere in the animal kingdom — for instance, in zebra finches — but evidence is rare.

In this study, researchers compared recordings of 19 resident Sarasota female dolphins when they were accompanied by their calves and when they had no calves present. In every case, when the females were with their calves, they increased the maximum frequency and the frequency range of their signature whistles. (Click on the video below to listen to the differences.)

This is an exciting finding of convergent evolution — when similar traits emerge in very different species. It indicates that studying dolphin vocalization and communication patterns will provide an important animal model for studying the evolution of animal use of sound.

• Study Citation: Sayigh, Laela S., N. El Haddad, P. L. Tyack, V. M. Janik, R. S. Wells, F. H. Jensen. 2023. Bottlenose dolphin mothers modify signature whistles in the presence of their own calves. The Proceedings of the National Academy of Sciences. 120 (27) e2300262120. Study link.

Until next month, here’s to a July filled with fair (and cooler) winds and following seas!

Randy Wells

Conservation Tip of the Month

Boat Dolphin-Safe

Did you know that most dolphin deaths & injuries from boat strikes in Sarasota Bay occur in the weeks surrounding the July Fourth holiday? Not only are there more boats on the water, but there are also new dolphin moms with naïve young calves in shallow seagrass beds and sandbars. Please remember to be a dolphin-safe boater whenever you’re on the water!



• Tip: Wearing polarized sunglasses will help cut through the water’s glare and allow you a better opportunity to see whether any marine animals are in your path so you can avoid them.

Boat safe to protect dolphin moms and babies — like F165 and the first calf of 2023, 1654, pictured below!

For more information on how you can help support wild dolphin research, please email Randy Wells, Director of the Sarasota Dolphin Research Program, or call 941.374.0449.

Dolphin Biology Research Institute — DBA Sarasota Dolphin Research Program — is dedicated to research and conservation of dolphins and their habitat. 

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