Sarasota Bay dolphin researchers dig deep to find family ties
Study of marine mammals takes advantage of their fulltime residency in area waters.
Sarasota Bay regularly attracts its share of visitors in the form of weekend boaters, fishing enthusiasts and sightseers.
But it’s also a multigenerational sanctuary for bottlenose dolphins, many of which exhibit human-like tendencies that form the basis of scientific study by the Chicago Zoological Society’s Sarasota Dolphin Research Program, the longest running examination of a dolphin population in the world.
More than just animals to fleetingly admire from a causeway or pleasure boat, dolphins have gotten to know the researchers (and vice versa) over the decades. Together, they are each learning what makes the other tick.
“You learn their patterns, you learn the kinds of dramas they’ve gone through in their lives, what kind of threats they face, how they get through those situations, what’s happened with their calves over times, and so you get a good sense of what they need in order to be able to survive and thrive.”Dr. Randall Wells
“They’re not just anonymous gray bodies out there,’’ said Dr. Randall Wells, who co-founded the project in 1970, 19 years before the Chicago Zoological Society became involved. Wells serves as program director.
“They are individuals who have been here far longer than most of the people have been, who have a social structure that is complex, a communication structure. They breathe the same air, they swim in the same water, eat the same fish as we do.”
Maddie, known scientifically as F213, is a 16-year-old female identifiable by her distinctly notched dorsal fin. She is part of “a lifelong and well-known female lineage in Sarasota Bay,” and is regularly observed on photo surveys by the team, which they do monthly aboard boats in the bay. Female dolphins have lived to the age of 67, males to 52.
SDRP operates from Mote Marine Laboratory and is operated by the Chicago Zoological Society. Researchers estimate there are roughly 170 year-round dolphin residents of Sarasota Bay.
Maddie is known to regularly frequent an area near New College of Florida, where the team can count on seeing her with relative consistency.
Researchers learn the signature whistles from individual dolphins during catch-and-release health assessments, then listen for their unique sounds through an underwater listening system that also records the myriad sounds under the bay, including those of manatee, fish, invertebrates and boats.
F165 is a 24-year-old female dolphin identifiable by two notches high on her dorsal fin. She is the one of the longest running subjects of the SDRP’s research, first observed in 1999 with her mother, FB75. She recently gave birth to the first calf of 2023, her fourth. The program has recorded 628 sightings of her.
“You learn their patterns, you learn the kinds of dramas they’ve gone through in their lives, what kind of threats they face, how they get through those situations, what’s happened with their calves over times, and so you get a good sense of what they need in order to be able to survive and thrive,” Wells said.
It’s that sense of underwater ancestry that inspires researcher Kylee DiMaggio.
“I love being on the water,’’ DiMaggio said. “I love tracking our new births. All that good stuff. A lot of the research that I'm interested in has to do with calving. So when I see new baby, I get really excited.
Though the research team does not engage with or positively reinforce their presence in the interests of research integrity, and the requirements of federal wildlife regulations, they have observed behaviors that indicate a passively friendly relationship between the researchers and the dolphins.
“We’re trying to study the animals as they’re making their living, so we observe them on a monthly basis and from a distance, (using) an approach that allows us to stay nearby to collect the data we need,” Wells said. “Sometimes they’ll come over and check us out, they sometimes will leave their calf with us while they go off and have coffee, or whatever the moms do ... So we believe there is a certain level of recognition, that they can distinguish between vessels based on the sounds they make.”
The number one threat to dolphins is recreational fishing gear, most of it in actual use — not discarded line or hooks, which can tangle and hook dolphins. The mammals can also ingest fishing gear.
The team has seen about a 2% increase in dolphin population as a result of their work. Researchers say updates to how runoff and sewage water is treated, in effect since the 1990s, have been beneficial to the ecosystem in general, with more to come as Sarasota County pursues new and different strategies to further improve bay waters with more advanced treatment methods and upland efforts to control runoff.
“About a quarter of identifiable deaths in the area are from human sources, and 19% to 20% of that is fishing gear,” Wells said, adding anglers can make a big difference by simply taking a break when dolphins are seen nearby, avoiding braided fishing line that can cut into dolphins’ flesh and by using fish hooks that corrode over time in salt water.
F165’s mother died in 2006 as a result of ingesting a fishing lure.
“I’m not advocating not fishing, just be careful about when fishing is occurring and under what circumstances, making sure the other creatures of the bay are staying safe while you’re enjoying the bay as well,” Wells said.
It’s that sense of Sarasota Bay as a community, which attracts newcomers and retains longtime residents, that makes the region special ... for a variety of reasons.
“There are just very few places in the world where you can track animals for five or six generations because a lot of the marine mammal populations are migratory,’’ DiMaggio said. “So being able to know who the dolphins are (and) track their lives is really unique to Sarasota."
This story is courtesy of the Community News Collaborative, made possible by a grant from Charles & Margery Barancik Foundation. You can reach Catherine Hicks at firstname.lastname@example.org
What is the Sarasota Dolphin Research Program?
Growing up in Illinois, marine biology and oceanography may not have been Dr. Randall Wells’ first career choice, but with an annual family vacation to Florida each year, Wells quickly developed an affinity for marine studies.
“In the middle of high school, my family was able to move to Sarasota ... not far from where I live now. I went to Riverview High School for my junior and senior years. I was able to take classes in marine biology and oceanography and get to know the Mote Marine Laboratory,” Wells said.
Through a professional connection his father had, Wells secured a summer internship with Blair Irvine, who founded the Sarasota Dolphin Research Program while Wells was his assistant.
Irvine, though retired, serves as vice president of the non-profit, Dolphin Biology Research Institute, a partner organization established in 1982 in Sarasota in support of long-term research and conservation.
The SDRP provides an opportunity to scientists to study marine mammal interactions in a natural laboratory setting that, for many of these specific animals, only exists in Sarasota Bay.
“We’re getting to learn a lot about how the human population in Sarasota influences animals, and we are really able to be stewards for marine mammals in general because there are very few places that have the knowledge that we have here in Sarasota,” said research assistant Kylee DiMaggio.
In the 53 years since the SDRP began, it has evolved from its modest early beginnings to a complex research, conservation and education program.
The program has trained 480 interns, hosted more than 200 international colleagues and students, many of whom attempted to replicate the natural laboratory concept in their own ecosystems, mentored 98 graduate students who have performed their capstone research in partnership, and welcomed more than 1,000 citizen scientists visiting to learn about dolphin conservation.
“It’s great for us to know how the animals act in the wild so that we can make suggestions for how they are managed in care facilities to make sure that animals (there) have the best and most natural life possible,” said DiMaggio.
— Catherine Hicks