Dolphin Tracking

A mother and calf pair of Risso’s dolphins stranded near Bonita Beach, Fla., on May 4, 2007. The animals were rehabilitated at Mote’s Dolphin and Whale Hospital and released early Thursday, Sept. 27, 2007, marking the first time a cow and such a young dependent calf have been rehabilitated and released in the Southeast Region of the U.S. Marine Mammal Stranding Network.

The dolphins, nicknamed Betty and Big Al, came to Mote’s Dolphin and Whale Hospital after stranding with another mother/calf pair of Risso’s dolphins. Mote staff responded to the stranding with members of the Florida Fish and Wildlife Conservation Commission Law Enforcement Division, the Florida Fish and Wildlife Research Institute and Dr. Janet Whaley, veterinarian of the Marine Mammal Health and Stranding Response Program of the National Oceanic and Atmospheric Administration Fisheries Service after a group of citizens found the dolphins on the beach. All four dolphins were transported to Mote but two of the animals died. (Read more about the rehabilitation of Betty and Big Al.)

Betty and Big Al were treated for numerous infections and, finally, were deemed healthy for release by NOAA Fisheries Service, which oversees the protection and rehabilitation of wild marine mammals.

Rehabilitated dolphins are generally released as close as possible to the area where they stranded, and in a known habitat for the animals. Risso’s dolphins, (Grampus griseus), are found in deep, temperate ocean waters worldwide. (Learn more about Risso’s dolphins.)

With the generous help of Tampa Bay residents Cathy Unruh and Tom Sansone, who donated the use of their 80-foot Lazzara yacht Tomcat for the release, Mote staff was able to return Betty and Big Al to the wild at 8 a.m. Thursday, 9-27-07.

In addition to learning more about the diseases that affect this species of dolphin, the rehabilitation allowed researchers to closely observe a mother-calf pair and learn more about how they interact, grow and develop, said Dr. Charles Manire, Mote’s chief veterinarian. “One thing we were able to watch was how quickly the calf grew,” Manire said. “When these animals arrived, Big Al weighed 31.5 kg (about 70 pounds) and was about 125 cm (49 inches) long. When we released them on Thursday, he weighed in at 95.5 kg (more than 210 pounds) and had grown to 199 cm (more than 6.5 feet). We also found them to be extremely playful, interacting both with each other and with the environmental enrichment devices provided for them.”

Before being released, both dolphins were tagged so that Mote staff could track their whereabouts and monitor their return to the wild. Follow-up monitoring allows scientists to evaluate whether rehabilitation efforts have been successful, as well as learn more about individual animals. In the case of Risso’s dolphins -- since not much is known of their behavior in the wild -- post-release monitoring should help researchers learn valuable information about this species.

Both mother and calf were tagged with small VHF radio transmitters that allow for line-of-sight monitoring. That allowed Mote staff to know where both animals were as soon as they were released. Additionally, Betty was tagged with a satellite-linked transmitter that now allows Mote to monitor her movements remotely. The satellite tag records data on Betty’s location and how long and deep she dives.

This marks the second time that Mote has rehabilitated and released a Risso’s dolphin and only the third time any have been rehabilitated and released in the U.S.

Clyde, treated and released in 2006, was monitored via satellite-linked transmitter for 23 days after his release. Researchers tracked his movements from near the edge of the Continental Shelf off central west Florida, around the Florida Keys, down to Cuba, and then to the Continental Slope off Delaware in the Atlantic Ocean. Clyde provided new information about the behavior of this species in the wild. Researchers documented one dive to 400 to 500 meters -- 1,300 to 1,600 feet -- representing the deepest dive ever recorded for this species. More than 99 percent of his dives were to less than 50 meters, or 160 feet. (Look below for a link to Clyde’s map.)

“Follow-up monitoring of rehabilitated animals is very important,” said Dr. Randall Wells, manager of the Dolphin Research Program at Mote, a partnership with the Chicago Zoological Society. “Tracking allows us to monitor the dolphins’ condition and learn more about the species. Although Risso’s dolphins are commonly seen on offshore survey cruises, very little is known about their individual ranging and dive patterns. We are looking forward to gaining more data to further rehabilitation efforts, research and the overall knowledge of the species.”

The satellite-linked transmitter was provided by NOAA’s John H. Prescott Marine Mammal Rescue Assistance Grant Program. NOAA is interested in learning more about what kinds of rehabilitation efforts are successful, and about the biology of the species in the wild that are under the agency’s protection.

Mote wishes to thank Cathy Unruh and Tom Sansone for providing transportation for the release of Betty and Big Al and for their previous support during Clyde’s release. Dolphin rehabilitation would be much more difficult without the hard work by the numerous volunteers who become actively engaged in rehabilitation and without the extremely generous support of donors who help provide financially for the care of animals in rehabilitation. (Find out how you can help.)

Where is Betty today?

About Clyde
Clyde is a Risso’s dolphin that was rehabilitated at Mote’s Dolphin and Whale Hospital from July 2005 until he was released in February 2006. Click the link to see where his travels took him after his release. Click here to learn more about his rehabilitation.
(Map citation: Wells, R.S., C.A. Manire, D. Smith, J.G. Gannon, D. Fauquier, and K.D. Mullin. In review. First records of movements and dive patterns of a Risso’s dolphin, Grampus griseus, in the Gulf of Mexico and Atlantic Ocean, from a rehabilitated individual. Marine Mammal Science.)
Watch a movie about Clyde.

 

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Mote Marine Laboratory has been a leader in marine research since it was founded in 1955. Today, we incorporate public outreach as a key part of our mission. Mote is an independent nonprofit organization and has seven centers for marine research, the public Mote Aquarium and an Education Division specializing in public programs for all ages.

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