Movement patterns of juvenile hawksbill turtles Eretmochelys imbricata at a Caribbean coral atoll: long-term tracking using passive acoustic telemetry

Mg Chevis,J Jackson Lewis,Kl Scales,Rt Graham,Bj Godley,Jp Lewis

doi:10.3354/esr00812

Abstract

ESR Endangered Species Research Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials ESR 32:309-319 (2017) - DOI: https://doi.org/10.3354/esr00812 Movement patterns of juvenile hawksbill turtles Eretmochelys imbricata at a Caribbean coral atoll: long-term tracking using passive acoustic telemetry Megan G. Chevis1,2, Brendan J. Godley1, James P. Lewis3, Julie Jackson Lewis2, Kylie L. Scales4,5, Rachel T. Graham2,* 1Centre for Ecology and Conservation, University of Exeter, Penryn Campus, TR10 9EZ, UK 2MarAlliance, 32 Coconut Drive/PO Box 283, San Pedro, Ambergris Caye, Belize 3Amphibian Survival Alliance, International Conservation House, 7078 Airlie Road, Warrenton, VA 20187, USA 4Institute of Marine Sciences, University of California, Santa Cruz, CA 95064, USA 5NOAA Southwest Fisheries Center, Environmental Research Division, 99 Pacific Street, Suite #255A, Monterey, CA 93950, USA *Corresponding author: rachel@maralliance.org ABSTRACT: Understanding the ecological interactions that underlie marine ecosystem functioning requires sufficient data describing habitat use by mobile species. Hawksbill turtles Eretmochelys imbricata are considered a key species in coral reef-associated communities, owing to their specific foraging preferences, yet new information is still revealing details of the spatial and temporal aspects of habitat use. We used passive acoustic telemetry to monitor the movements of 18 juvenile hawksbills (minimum curved carapace length: 32.0-59.7 cm, mean ± SD = 43.9 ± 6.7 cm) at a developmental foraging site in a Mesoamerican barrier reef, Lighthouse Reef Atoll in Belize (tracking duration 10-1414 d, mean ± SD = 570 ± 484 d). Although specific home ranges were difficult to quantify, several turtles showed high site fidelity over timescales of months to years, with occasional wide-ranging use of the atoll. Diel variation in the number of detections received strongly suggest nocturnal resting. Long-term tracking data reveal 3 degrees of site fidelity across the atoll, based on the number of detection days near individual stations: high residency (n = 4 turtles), sequential residency (n = 5), and transient behavior (n = 4). These variations in movement raise questions about the differentiation of foraging habitats and degree of individual specialization within this population, as well as the influences of microhabitats and human disturbance. KEY WORDS: Spatial ecology · Home range · Belize · Habitat use · Site fidelity · Marine megafauna · World Heritage Site Full text in pdf format Supplementary material PreviousNextCite this article as: Chevis MG, Godley BJ, Lewis JP, Jackson Lewis J, Scales KL, Graham RT (2017) Movement patterns of juvenile hawksbill turtles Eretmochelys imbricata at a Caribbean coral atoll: long-term tracking using passive acoustic telemetry. Endang Species Res 32:309-319. https://doi.org/10.3354/esr00812 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in ESR Vol. 32. Online publication date: March 28, 2017 Print ISSN: 1863-5407; Online ISSN: 1613-4796 Copyright © 2017 Inter-Research.

Highlights

With the host of anthropogenic threats that tropical marine ecosystems are currently facing, our understanding of the processes that regulate biodiversity within these ecosystems becomes increasingly important (Gardner et al 2003, Halpern et al 2008)
Such specialization suggests that hawksbill foraging ecology plays a critical role in shaping coral reef systems, since the species preferred by these turtles have the potential to outcompete corals without top-down control (Meylan 1988, Hill 1998, León & Bjorndal 2002)
As in other coral reef systems (Pilcher et al 2015), hawksbills, green turtles Chelonia mydas, and loggerhead turtles Caretta caretta are found in a mixedspecies aggregations at Lighthouse Reef Atoll (LRA), with hawksbills the most commonly sighted species

Summary

Introduction

With the host of anthropogenic threats that tropical marine ecosystems are currently facing, our understanding of the processes that regulate biodiversity within these ecosystems becomes increasingly important (Gardner et al 2003, Halpern et al 2008). Juveniles are thought to show high site fidelity within these developmental habitats, maintaining a small home range for extended periods, with individuals selecting different microhabitats depending on size or ontogenetic stage (van Dam & Diez 1998, Blumenthal et al 2009a, Wood et al 2013). Their feeding ecology remains poorly understood, hawksbills are known to feed on a range of reef-associated invertebrates, with sponges forming a major part of the diet of older juveniles and adults (Carr & Stancyk 1975, Meylan 1988, León & Bjorndal 2002). As the largest spongivore in most Caribbean reef systems, hawksbill populations will likely be impacted by shifts in coral reef assemblages and sponge mortality events (Lessios 1988, Meylan 1988, Hughes 1994, Wulff 2006)

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