We’ve got some exciting news to share about our ongoing efforts to conduct health assessments of offshore dolphins: In September, we were able to conduct assessments and tag four dolphins over the West Florida Shelf. The SDRP is leading this project, which involves a multi-institution team funded by the Florida RESTORE Act Centers of Excellence Program, through the Florida Institute of Oceanography.
The project involves hoop-netting individual dolphins (focusing primarily on bottlenose or Atlantic spotted) up to 50 miles offshore, over the West Florida Shelf, performing a health assessment, and tagging them for monitoring movements and dive patterns. We have now completed the first two of four planned field sessions.
During the first session, we caught, sampled, and tagged an adult female Atlantic spotted dolphin, nicknamed Eugenie Clark, after the founder of Mote Marine Laboratory, where the SDRP started in 1970.
This map shows dolphin Eugenie Clark’s movements after tagging.
During her health assessment and lung-function tests, she was given both a satellite-linked time, depth and location tag and a short-term digital archival tag, known as a DTAG. The satellite-linked tag, tracked for 106 days until Sept. 14, showed that she ranged 25-50 miles offshore from Tampa Bay to Englewood, Florida, and dove as deep as 147 feet for up to 4-5 minutes.
Building on our success in June, the team returned to the field September 19-23, and tagged four more dolphins:
- Two bottlenose dolphins — nicknamed Sylvia, after Her Deepness, ocean conservationist Sylvia Earle, and Ken, after Ken Norris, who was one of the founders of the field of marine mammal science and instrumental in developing the federal Marine Mammal Protection Act;
- One rough-toothed dolphin — nicknamed Sam, after Sam Houston Ridgway, who is considered the founder of marine mammal medicine and who founded the National Marine Mammal Foundation;
- And one Atlantic spotted dolphin — nicknamed Bill, after Bill Perrin, who was a pioneer in dolphin taxonomy, life history, population ecology, conservation and behavior, and another of the forces behind the Marine Mammal Protection Act.
Rough-toothed dolphin Sam upon release.
The animals were caught 20-41 nautical miles offshore of the Sarasota area. All but Sam received both a satellite-linked tag and a DTAG. The DTAG remained on the large adult male bottlenose dolphin Ken for the entire programmed period, and showed him to begin diving to the seafloor and feeding within 5 minutes of release.
Initial findings show all but Sam diving to the seafloor — he remained at depths less than 52 feet.