A pilot study on surgical implantation and efficacy of acoustic transmitters in fifteen loggerhead sea turtles (Caretta caretta), 2021–2022

By Charles J. Innis, Adam Kennedy, Jeff Kneebone, Sarah Perez, Linda Lory, Sarah DiCarlo, Alessia Brugnara, Kristen Luise, Deana Edmunds, Christine Sinnigen, Mary Beth Tims, Nina Nahvi, Emily JonesMelissa Joblon, Kathryn Tuxbury, Elizabeth Burgess, Vickie Zhou, Nina Fischer, and Kara L. Dodge

Originally published in Animal Biotelemetry in November 2023



Background: The ability to detect the location of free-ranging sea turtles over time is desirable for ecological, conservation, and veterinary studies, but existing detection methods have limited sensitivity or longevity. Externally attached acoustic transmitters have variable, and sometimes short retention times for sea turtles. For several vertebrate taxa, surgically implanted acoustic transmitters have proven to be safe and effective for long-term detection; however, implanted transmitters have not yet been used for turtles.

Results: In this pilot study, INNOVASEA acoustic transmitters were surgically implanted subcutaneously in the pre-femoral region of fifteen hospitalized loggerhead sea turtles (Caretta caretta) that had been rehabilitated after stranding due to cold-stunning. Model V16-4H transmitters (estimated battery longevity = 2435 days) were implanted in turtles measuring ≥ 50 cm straight carapace length (SCL), and model V13-1H transmitters (estimated battery longevity = 1113 days) were implanted in turtles measuring 30–49 cm SCL. Incision healing was monitored over several months prior to release. Twelve turtles’ incisions healed without complication, on average, 55 days after surgery (median 47, range 41–100). Three turtles experienced incision complications, two of which healed after a second surgery, while the third required transmitter removal to promote healing. One of the fourteen implanted transmitters was confirmed to be dysfunctional prior to release, although it had been functional prior to implantation. To date, 100% of turtles released with functional acoustic transmitters (n = 13) have been detected a total of 915 times by 40 individual acoustic receivers off the coasts of Massachusetts, Rhode Island, New York, Virginia, North Carolina, and in southern New England offshore waters. Turtles with transmitters generated 5–235 detections (mean 70, median 43) on 1–13 individual acoustic receivers (mean 5, median 5) for periods of 3–400 days post-release (mean 118, median 87). Total detections and detection durations for these individuals are expected to increase over time due to anticipated transmitter battery longevity.

Conclusions:This study demonstrates that surgically implanted acoustic transmitters are effective for the detection of free ranging sea turtles, but refinement of surgical methodology is needed in light of the observed complications. Monitoring of healing is critical when evaluating novel surgical techniques in wildlife.

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Affiliated Authors
  • Dr. Charles Innis

    Charles Innis, VMD, DABVP (RA), Senior Scientist and Veterinarian, Anderson Cabot Center for Ocean Life

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  • Adam

    Adam Kennedy, Director of Rescue and Rehabilitation, Animal Care, New England Aquarium

  • Jeff Kneebone

    Jeff Kneebone, PhD, Senior Scientist, Fisheries Science and Emerging Technologies Program, Anderson Cabot Center for Ocean Life

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  • Emily Jones

    Emily Jones, Scientific Program Officer, Fisheries Science and Emerging Technologies Program, Anderson Cabot Center for Ocean Life

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  • Dr. Melissa Joblon

    Melissa Joblon, DVM, Director of Animal Health, Animal Care, New England Aquarium

  • Kathy Tuxbury

    Kathryn Tuxbury, DVM, Senior Veterinarian, Animal Care, New England Aquarium

  • Elizabeth Burgess

    Elizabeth Burgess, PhD, Research Scientist and Chair, Wildlife and Ocean Health Program, Anderson Cabot Center for Ocean Life

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  • Kara Dodge

    Kara Dodge, PhD, Research Scientist, Fisheries Science and Emerging Technologies Program, Anderson Cabot Center for Ocean Life

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Through pioneering conservation research and strategic partnerships, our team of 40 scientists at the Anderson Cabot Center for Ocean Life works to combat the unprecedented impacts on the ocean from climate change and other human activities.