Observations from boats gives us context to better understand wild dolphin ecology.
Social behavior, foraging, communication, health, and habitat use are all tied together by observational data.
When we began in 1970, we had to devise ways to study wild dolphins. Most bottlenose dolphins look the same. They move constantly. Dolphins surface briefly to breathe only about twice each minute.
Estuarine waters, such as Sarasota Bay, are not very clear. So, dolphins typically disappear from sight when they submerge.
Observations from boats gives us context to better understand wild dolphin ecology.
To tell the dolphins apart we started by photographing naturally marked dolphins and tagging others. By now, virtually all of the 160 or so dolphins in the Sarasota resident community are identifiable.
Year round, the SDRP team conducts photo-identification surveys at least 10 times a month. Volunteers and student interns provide invaluable help.
Dive deeper to see the most recent Dolphin Survey report.
The data sheet is filled out for each dolphin sighting.
When dolphins are sighted, the boat pauses. Individual dolphins are identified as possible by the SDRP skipper. They are usually photographed for later verification identities.
Data are collected on who is present, the location, what they are doing, how many are in the group, and how many calves of different age classes are present. Environmental data like depth, tide, water temperature etc are also collected. Then the survey boat moves on.
Dolphins are not usually seen alone. Except for moms and calves, most dolphins often are seen and with many different companions.
Year-round monthly monitoring of the Sarasota dolphin community has been made possible with support from NOAA Fisheries Service, support from the Batchelor Foundation to the Chicago Zoological Society, Disney Worldwide Conservation Fund, and the Chicago Zoological Society.
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About a thousand groups are sighted during surveys in a year – about 2500-3200 dolphins total. Across the months, the surveys will average 8-9 sightings, seeing 20-30 dolphins per day. Big groups, numbering about 20 dolphins, are usually sighted only a few times each year.
The first observation of F175's third calf. From sighting records of F175, we know that this calf is less than one week old in this picture.
Calves, and especially YoYs (young-of –the-year), are a favorite of the survey teams, because of the antics of the babies. One to 19 new dolphin calves will be sighted each year. Because of the frequency of the surveys and the marked
The last sighting of 54-yr-old Ms. Mayhem alive. She appeared to be skinny, and she had two visible shark bites. Her body was recovered just nine days later. Due to tissue decomposition, cause of death was undetermined.
seasonality of calving, the approximate age of the calves is usually known to within a week or two.
At the other end of the continuum, the surveys sometimes can document the decline of older dolphins, who then disappear or wash up dead. By year’s end, disappearances of known dolphins coupled with bodies recovered by Mote Marine Lab’s Stranding Investigations Program allow us to quantify the losses of dolphin community members.
So what’s a survey like? Usually it’s a 5-7 hour boat ride following a prescribed route; 20-40 miles round trip depending on time available and wind conditions.
Intern prepares to compare dorsal fin pictures to verify a dolphin’s identity
It’s a long day, made even longer by the subsequent time back in the lab. Photographs are cataloged. The sighting sheets are checked for accuracy and completeness.
Dolphin identifications are verified as necessary with photos of each known dolphin in the master file. Then the data are entered into the computer database.
All photos © Sarasota Dolphin Research Program under NMFS permit #522-1785
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Long-term volunteer takes identification photos during dolphin survey in Sarasota Bay
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A group of six recognizable dolphins, including a mom and calf.
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The data sheet is filled out for each dolphin sighting.
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The first observation of F175′s third calf. From sighting records of F175, we know that this calf is less than one week old in this picture.
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The last sighting of 54-yr-old Ms. Mayhem alive. She appeared to be skinny, and she had two visible shark bites. Her body was recovered just nine days later. Due to tissue decomposition, cause of death was undetermined.
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Intern prepares to compare dorsal fin pictures to verify a dolphin’s identity
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F148 & F217 leap while socializing
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Dolphins socializing
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1315, F131, C834, F182 briefly swim in formation
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