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An adult female franciscana is released by Aquamarina and SDRP research team members following tagging. The Argentinians received training through internships with the SDRP in Sarasota in recent years

During most years since 2005, SDRP staff and volunteers, in collaboration with Disney’s Animal Programs staff, have traveled to Argentina to assist the  Fundacion Aquamarina conservation research team.

Conservation scientist Pablo Bordino leads the Aquamarina cadre of students, colleagues, and fishermen.

The goal in recent years has been to conduct additional satellite-linked tagging of the Franciscana dolphins in order to define their ranging patterns relative to gillnet fisheries, and to learn about their dive patterns relative to fishing practices.

Of particular interest is trying to see where the dolphins spend their time in the water column relative to where the nets are set. Tagging and tracking work during suggested residency to both Bahia Samborombon and Bahia San Blas for up to six months.

Locations of satellite-linked radio tagged franciscana dolphin in Argentina

This information is of critical value for conservation. Dive depth information helps inform recommendations for the type of fishing nets to be used. Surfacing information may help scientists and wildlife managers to develop correction factors for surface and aerial surveys to estimate abundance.

Four dolphins (two male/female pairs) were tagged, three with TDR tags and one with a location-only tag. The tags continued to transmit for two to nearly six months.

The franciscana research team in Bahia Samborombon, Argentina, March 2010.

Tracking results indicated that as before, the dolphins remained in a fairly localized area. Most of the dives were shallow, although dives to the bottom did occur. At least one dolphin may be a multi-year resident, and analysis suggested the possibility of long term breeding associations (which would be quite different from the Sarasota dolphin community).

Major support for this project was provided by Disney’s Animal Programs and the Chicago Zoological Society. Tags and tag data processing support were provided by Dolphin Quest. National Geographic Society for 2010

Oceanic bottlenose dolphin with radio tag on dorsal fin

Little is known about the movements and activities of Bottlenose dolphins off Bermuda.

They are difficult to observe because ocean-going boats are needed for observation. Compared to conditions in Sarasota, dolphin surveys are much more difficult. Ocean-going boats are needed. Sightings are hampered by sea and weather conditions, and by longer dolphin submergence in the deeper water.

Dolphin Quest Inc., a long time supporter and collaborator in Sarasota, initiated a project in 2003 to study these dolphins using radio tracking. In 2005, SDRP Program Manager, Randy Wells assisted again, with the capture, sampling, and outfitting of three dolphins with satellite-linked and VHF transmitters. The dolphins were tracked for 12, 14, and 46 days.

Two of the dolphins traveled to a Seamount, located over 200 km away before their tags ceased transmitting.

The third dolphin remained within 60 km of Bermuda, and made similar movements to three dolphins tracked in 2003 for 45 days. This dolphin, and the three tagged in 2003, stayed in water depths ranging from 1,000-1,400 m.

Local movement patterns, along with year-round dolphin sightings, suggest there may be a resident population of dolphins around Bermuda. Or, Bermuda waters may be a stop-over site of a larger home range [DL/ASD/Communities], as suggested by the longer-ranging movements by the two dolphins to the sea mount.

Oceanic Bottlenose dolphin with radio tag

Dive data collected from the time-depth recorders on the satellite tags revealed that dive-times by the three dolphins was usually less than five minutes, but several dives were 10 – 11 minutes. By comparison, Sarasota dolphins usually breath about twice a minute.

All three dolphins made dives beyond 600 meters. One dolphin dove to depths between 800 – 900 meters. These are the deepest recorded dive depths and durations for wild bottlenose dolphins on record.

Future research plans include a genetic study of these dolphins, as well as a photo-id study, to help determine if these animals should be managed as a local population or as part of a larger oceanic population.

This project was funded by Dolphin Quest Inc. / Quest Global Management, with additional support from the Bermuda Zoological Society, and the Chicago Zoological Society.

For four decades, the core of the Sarasota Dolphin Research Program has been the ability to identify individual dolphins.

In 1970, we began attaching visual tags to tell them apart, and we used natural marks to help with the identification. But visual tags don’t tell the researcher where the dolphin goes or does when out of sight. For that, we need radio telemetry.

Designs and technology tested in Sarasota are used in studies around the world.

In 1974 we began attaching radio transmitters to monitor dolphin movements. Because our year-round surveys allow us to monitor the fates of tags, Sarasota has proved to be the ideal testing place for tagging methods. Designs and technology tested in Sarasota are used in studies around the world.

The “roto-radio,” a small VHF transmitter that was attached to a small cattle ear tag (“roto tag”)

The first radio tags were thick enough to stand up to rough treatment by the dolphins. Over the years, transmitters became smaller and more sophisticated. As tag size decreased, our attachment methods increased in sophistication as well, as did technology to have the tags drop off the dolphin after prescribed time periods.

Radio transmitter collects time and the depth records of this spotted dolphin in the Eastern Tropical Pacific.

In the early 1990’s we developed the “roto-radio,” a small VHF transmitter that was attached to a small cattle ear tag (“roto tag”).

Suction cup tag initially tested in Sarasota can collect water and fin temperature readings for 1-2 days.

New tags, such as the Trac Pac are more hydrodynamic, and fit to the dorsal fin better using materials adapted from the human prosthetics field to reduce the risk of injury to the dolphins.

Radio tag attached with suction cups is tested in Sarasota

One Trac Pac product was the “bullet tag” which improved upon the roto-radio by placing the VHF transmitter in a prosthetic plastic housing. This is a commonly used tag configuration for dolphin radio-tracking.

Other tags, using only suction cups have also been designed to record depth, temperature and pitch data, but they fall off with a day or two at most.

Despite the advances in tag design, we still are searching for methods that reliably allow tag attachments of several months or a year, yet have a very low risk of damage to the dorsal fin and the dolphin. New federally funded research is addressing these issues.