Epibiosis Research of Sea Turtle Barnacles
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Sea Turtles 911


male sea turtle with epibiota on plastron Sea Turtles 911 volunteers carry an adult male green turtle with an overgrowth of epibionts on the plastron shell.

There are more than 50 species of marine invertebrates that attach and grow on sea turtles. These animals are known as epibionts, which commonly include barnacles. Since they travel whereever the turtle goes, getting a free mobile ride like hitchhikers do, studying epibionts may provide indirect tracking clues as to where the turtle has been feeding, resting, or nesting. During the 37th International Sea Turtle Symposium in 2019, Standardizing Sea Turtle Epibiont Sampling was discussed by experts, where they encouraged researchers globally to submit epibiont samples to the Peabody Museum of Natural History at Yale University. With international protocols in place, scientists are sharing and learning more about the epibiont communities that inhabit sea turtles, and in turn, are acquiring more insight into the lives of sea turtles and how their habitats are connected to each other.

Removing epibionts attached to the host turtle may harm the turtle in the process, so volunteers for Sea Turtles 911 do not pry barnacles off turtles in Hawaii. Instead, volunteers conduct preliminary research by identifying, characterizing, and photographing epibionts on green turtles to advance research in this niche field. When a barnacle is found, please take photos of the barnacle itself and also photos clearly showing where the barnacle is located in relation to the entire body of the turtle. From the photographic data, we can document the movement of barnacles, as it was discovered in Moriarty (2008) that barnacles can travel across the carapace of a turtle. This has never been documenting in Hawaiian green turtles and their basking behavior may have an influence on this phenomenon.

sea turtle with barnacles on plastron
A before and after picture of the same hawksbill sea turtle with and without epibiotic barnacles.

Research Publications on Sea Turtle Epibiosis:

  1. Domenech (2015) Epibiont communities of loggerhead marine turtles (Caretta caretta) in the western Mediterranean: influence of geographic and ecological factors.

  2. Frick (2010) A New Stomatolepas Barnacle Species from Leatherback Sea Turtles.

  3. Frick (2013) Sea Turtle Epibiosis In: The Biology of Sea Turtles Vol. 3. pp. 399–426.

  4. Lim (2021) Abundance, placement and sexual identity of the epizoic barnacle Chelonibia testudinaria relative to the size and species of host turtles in Mabul Island, Malaysia.

  5. Moriarity (2008) Directional Locomotion in a Turtle Barnacle, Chelonibia testudinaria, on Green Turtles, Chelonia mydas.

  6. Nolte (2020) Stable isotopes and epibiont communities reveal foraging habitats of nesting loggerhead turtles in the South West Indian Ocean.

  7. Pearson (2019) Distinguishing between sea turtle foraging areas using stable isotopes from commensal barnacle shells.

  8. Robinson (2016) Assortative epibiosis of leatherback, olive ridley and green sea turtles in the Eastern Tropical Pacific.

  9. Robinson (2019) Spatial distribution of epibionts on olive ridley sea turtles at Playa Ostional, Costa Rica.

  10. Sloan (2014) Substratum fidelity and early growth in Chelonibia testudinaria, a turtle barnacle especially common on debilitated loggerhead sea turtles.

  11. Schofield (2008) Larval Development and Complemental Males in Chelonibia Testudinaria, a Barnacle Commensal with Sea Turtles.

  12. Zardus (2007) Two Previously Unreported Barnacles Commensal with the Green Sea Turtle in Hawaii and a Comparison of their Attachment Modes.

  13. Zardus (2013) Deconstructing an Assemblage of “Turtle” Barnacles: Species Assignments and Fickle Fidelity in Chelonibia.

  14. Zardus (2021) A Global Synthesis of the Correspondence Between Epizoic Barnacles and Their Sea Turtle Hosts.