Bahamas connection: residence areas selected by breeding female loggerheads tagged in Dry Tortugas National Park, USA

Animal Biotelemetry
By: , and 

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Abstract

Background

Delineation of home ranges, residence and foraging areas, and migration corridors is important for understanding the habitat needs for a given species. Recently, many population segments of Northwest Atlantic loggerhead sea turtles (Caretta caretta) were designated as endangered or threatened; the smallest subpopulation is in the Dry Tortugas. Foraging and residence areas for this subpopulation have not been defined outside the Gulf of Mexico. Here, for Dry Tortugas loggerheads that traveled to the Bahamas, we use a combination of switching state-space modeling (SSM) and home-range estimators to determine migration period, spatially delineate and describe residence areas, and examine inter-annual home-range repeatability.

Results

In 5,973 tracking days, migration dates for Dry Tortugas loggerheads traveling to the Bahamas occurred during July–September, with turtles tracked twice showing remarkably similar migration paths and timing of departure from nesting sites. Core-use residence areas for 19 loggerheads ranged from 3.7 to 179.5 km2 (mean ± 1 SD = 56.2 ± 49.5 km2). For three turtles, we found inter-annual home-range repeatability, with centroids of core areas only 0.7–2.9 km apart and significant overlap of inter-annual 50% kernel contours.

Conclusions

We demonstrate a previously unknown link between Dry Tortugas nesting beaches and Bahamas residence areas; 17/39 (43.6%) of nesting loggerheads tagged in and tracked from the Dry Tortugas take up residence at sites in the Bahamas. Residence area estimates for these turtles were similar in size to previous foraging area estimates for two turtles tracked to the Bahamas in other studies. We show inter-annual residence area repeatability, and that residence areas of different individuals generally did not overlap. We suggest that these loggerheads possibly establish territories.

Study Area

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Bahamas connection: residence areas selected by breeding female loggerheads tagged in Dry Tortugas National Park, USA
Series title Animal Biotelemetry
DOI 10.1186/s40317-014-0019-2
Volume 3
Issue 3
Year Published 2015
Language English
Publisher BioMed Central
Publisher location London
Contributing office(s) Southeast Ecological Science Center
Description 17 p.
Country United States
State Florida
Other Geospatial Dry Tortugas National Park
Online Only (Y/N) N
Additional Online Files (Y/N) N