Novel Microsatellite Tags Hold Promise for Illuminating the Lost Years in Four Sea Turtle Species

Animals (Basel). 2024 Mar 14;14(6):903. doi: 10.3390/ani14060903.

Abstract

After hatching, sea turtles leave the nest and disperse into the ocean. Many years later, they return to their natal coastlines. The period between their leaving and their returning to natal areas, known as the "Lost Years", is poorly understood. Satellite tracking studies aimed at studying the "Lost Years" are challenging due to the small size and prolonged dispersal phases of young individuals. Here, we summarize preliminary findings about the performance of prototype microsatellite tags deployed over a three-year period on 160 neonate to small juvenile sea turtles from four species released in the North Atlantic Ocean. We provide an overview of results analyzing tag performance with metrics to investigate transmission characteristics and causes of tag failure. Our results reveal that, despite certain unfavorable transmission features, overall tag performance was satisfactory. However, most track durations were shorter than those observed on individuals of similar size in other studies and did not allow for detailed analyses of trajectories and turtle behavior. Our study further suggests that tracking durations are correlated with the targeted species, highlighting a lack of robustness against some neritic behaviors. Unprecedented diving data obtained for neonate sea turtles in this study suggest that the vertical behaviors of early juveniles are already too strenuous for these miniaturized tags. Our findings will help to inform the biologging research community, showcasing recent technological advances for the species and life stages within our study.

Keywords: North Atlantic Ocean; diving behavior; early juvenile sea turtle; lost years; microsatellite tag; performance analysis; satellite tracking.

Grants and funding

Funding to support field logistics (e.g., vessel operations and researcher travel and accommodations), tag testing in a field/lab setting, satellite tags and attachment materials, videography, and ARGOS satellite time was provided by Upwell Turtles. Turtle care and lab testing at Florida Atlantic University was supported by the Royal Caribbean Cruises Ltd., The National Save the Sea Turtle Foundation, and Upwell Turtles. The COSTA project, COnsolidating Sea Turtle conservation in the Azores, is financed by the U.S. Fish and Wildlife Service (Marine Turtle Conservation Fund n° F15AP00577, F16AP00626, F17AP00403, F18AP00321 and F21AS00370), Archie Carr Center for Sea Turtle Research through funds from Disney Conservation Fund (grant n° UFF F019479), and the Regional Directorate for Fisheries of the Azores Government. FV was supported by the Investigator Programme of the Fundação para a Cîencia e Tecnologia (FCT, CEECIND/03469/2017, CEECIND/03426/2020). IICM Okeanos is funded by FCT under the project UIDB/05634/2020 and UIDP/05634/2020, and by the Regional Government of the Azores through the initiative to support the Research Centers of the University of the Azores and through project M1.1. A/REEQ.CIENTÍFICO UI&D/2021/010.