Hawaiian Green Sea Turtle Migrations and GIS Analysis of Sea-Level Rise Scenarios on Maui

Brielle Jaglowski

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Brielle Jaglowski and a Hawaiian Green Sea Turtle.

Hawaiian green sea turtles (Chelonia mydas) are native to the archipelago and reproduce almost exclusively at a central site: French Frigate Shoals, an open atoll protected within the Papahānaumokuākea Marine National Monument.

Nesting sea turtles are tagged at French Frigate Shoals and migrate to other islands across the archipelago, but tag recoveries from Maui have not been reported in more than 20 years. Over the course of 5 weeks on the island of Maui, 106 green sea turtles were scanned for passive integrated transponder (PIT) tags and 9 tags were recovered. Recovered tags document migrations of sea turtles from East Island and Tern Island at French Frigate Shoals to Maui and from Hawai’i to Maui.

Original art by Brielle Jaglowski.

These results reflect past studies that document migrations of sea turtles from islands across the archipelago to breed at French Frigate Shoals. For the second part of the study, a GIS analysis was run on four different scenarios of sea-level rise for the island of Maui. The analysis suggests that main basking beaches for sea turtles will be inundated at the lowest and second-lowest scenarios of 0.5 m and 1.0 m rises in sea level. In addition, the breeding grounds at French Frigate Shoals are just above sea level and are threatened by changes in sea-level rise and storms. The many unknowns about Hawaiian green sea turtle ecology and threats to sea turtle nesting and basking habitat due to sea-level rise and increased storm intensities strongly support the need for extensive research and conservation efforts across the archipelago to preserve this species.