Sarasota Bay’s Dolphins Welcome 19 Calves as Scientists Mark 55 Years of Research

By Lisa Neff

In the waters of Sarasota Bay, a 41-year-old dolphin known as “Granny” added three more descendants to her growing family tree this year, cementing her status as matriarch of one of the world’s most thoroughly documented marine mammal populations.

The Sarasota Dolphin Research Program logged 19 new calves in 2025, with 15 thriving as of late fall — a bright spot in a year that also saw the community lose members to suspected vessel strikes, according to the nonprofit’s annual report.

Scientists say the births and comprehensive health data collected from the bay’s bottlenose dolphins provides crucial insights for marine conservation efforts worldwide after more than five decades of monitoring.

“This community remains one of the most thoroughly studied free-ranging dolphin populations in the world,” researchers Jason Allen and Kylee DiMaggio wrote in their report released in late November.

A 2025 health assessment in May examined 19 individual dolphins over 12 days, matching the previous year’s success despite challenging weather conditions. A team of 164 people working from 13 boats collected data, examining dolphins ranging from 3 years old to 35 years.

The physical exams revealed generally good health across the population. Eleven animals weighed up to 17 kilograms above their expected weight, while eight were slightly underweight. One female was in her first trimester of pregnancy. Veterinarians noted some lung health concerns for a 9-year-old male who had survived a severe shark attack when young.

Operating under Brookfield Zoo Chicago since 1989 and based at Mote Marine Laboratory since 1992, the program represents a collaborative model that has trained generations of marine scientists.

The program’s longevity has yielded an unprecedented dataset: more than 60,800 dolphin group sightings since 1970, producing 187,000 identifications of more than 6,000 individual dolphins along the central West coast.

Among 2025’s notable births, Granny’s lineage — tracked through a dolphin designated FB19 — welcomed a sixth-generation calf, born to 15-year-old F233 in October. The “mom club” also expanded with seven first-time mothers in 2025.

But the year brought losses underscoring ongoing threats to the dolphins. Scientists suspect vessel strikes killed 18-year-old Yogurt and 6-year-old C33A, both males whose remains were recovered by Sarasota-based Mote Marine Laboratory. Yogurt had deep propeller wounds and C33A showed injuries consistent with blunt force trauma. The program also lost 1316, a 14-year-old dolphin, and three 2024 calves were missing and presumed dead.

The Charles and Margery Barancik Foundation provides primary support for the year-round monthly monitoring, which relies heavily on local volunteers and undergraduate interns who spend 10 days on the water each month conducting photographic identification surveys.

Beyond births and deaths, researchers track individual dolphin conditions and watch for problems like fishing line entanglements, aiming to detect issues as early as possible in a population whose stories span generations — including one grandmother whose legacy extends six generations deep.