Stay or go? Space and resource use of the great hammerhead (Sphyrna mokarran) off Andros Island, The Bahamas

In light of global declines of upper-level marine predators, such as the great hammerhead, (Sphyrna mokarran) a thorough understanding of their behavioral ecology is needed for designing effective management strategies to preserve their key role in maintaining ecosystem functioning, stability, and r...

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Main Authors: T. L. Guttridge, V. Heim, S. Dedman, A. E. Guttridge, S. A. Bain, B. A. Keller, P. Matich
Format: Article
Language:English
Published: Frontiers Media S.A. 2025-03-01
Series:Frontiers in Marine Science
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Online Access:https://www.frontiersin.org/articles/10.3389/fmars.2025.1544482/full
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author T. L. Guttridge
V. Heim
S. Dedman
S. Dedman
A. E. Guttridge
S. A. Bain
B. A. Keller
B. A. Keller
P. Matich
author_facet T. L. Guttridge
V. Heim
S. Dedman
S. Dedman
A. E. Guttridge
S. A. Bain
B. A. Keller
B. A. Keller
P. Matich
author_sort T. L. Guttridge
collection DOAJ
description In light of global declines of upper-level marine predators, such as the great hammerhead, (Sphyrna mokarran) a thorough understanding of their behavioral ecology is needed for designing effective management strategies to preserve their key role in maintaining ecosystem functioning, stability, and resilience. Within the northwestern Atlantic, great hammerheads display regional connectivity between the U.S. East Coast and the western edge of The Bahamas, but despite the suggested importance of the Bahamian shark sanctuary towards regional population recovery strategies, relatively few data exist from other areas of The Bahamas. This study used fisheries-independent drumline captures, satellite telemetry, and bulk stable isotope analysis to advance our understanding of the residency, space use, and trophic role of great hammerheads in Andros, the largest island in The Bahamas. We examined movement behaviors and thermal range within the Bahamian Exclusive Economic Zone, and constructed Bayesian mixing models based on carbon, nitrogen, and sulfur isotope ratios to estimate the importance of prey species in the diet of great hammerheads. Our data revealed year-round residency of Andros-caught great hammerheads in Bahamian waters with site-fidelity to and high use of habitats along the reef-drop off and flats of Andros. Great hammerheads predominantly fed on barracuda and small-bodied elasmobranchs in Andros connecting food webs from the pelagic zone to the shoreline. This study expands our knowledge of the ecology of great hammerheads in the northwestern Atlantic and shows that, despite their highly-mobile nature, some individuals reside in the Bahamas year round. These findings suggest the Bahamian shark sanctuary could be more than just a seasonal refuge for this species as previously proposed, and merit further research to assess the conservation value of the sanctuary towards regional rebuilding goals for greathammerheads.
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spelling doaj-art-e59cfae43cb6429398bc722d08ea3f282025-08-20T02:41:14ZengFrontiers Media S.A.Frontiers in Marine Science2296-77452025-03-011210.3389/fmars.2025.15444821544482Stay or go? Space and resource use of the great hammerhead (Sphyrna mokarran) off Andros Island, The BahamasT. L. Guttridge0V. Heim1S. Dedman2S. Dedman3A. E. Guttridge4S. A. Bain5B. A. Keller6B. A. Keller7P. Matich8Saving the Blue, Davie, FL, United StatesSaving the Blue, Davie, FL, United StatesSaving the Blue, Davie, FL, United StatesInstitute of Environment, Department of Biological Sciences, Florida International University, North Miami, FL, United StatesSaving the Blue, Davie, FL, United StatesSaving the Blue, Davie, FL, United StatesSaving the Blue, Davie, FL, United StatesNational Oceanic and Atmospheric Administration (NOAA) Fisheries, Office of International Affairs, Trade, and Commerce, Silver Spring, MD, United StatesSaving the Blue, Davie, FL, United StatesIn light of global declines of upper-level marine predators, such as the great hammerhead, (Sphyrna mokarran) a thorough understanding of their behavioral ecology is needed for designing effective management strategies to preserve their key role in maintaining ecosystem functioning, stability, and resilience. Within the northwestern Atlantic, great hammerheads display regional connectivity between the U.S. East Coast and the western edge of The Bahamas, but despite the suggested importance of the Bahamian shark sanctuary towards regional population recovery strategies, relatively few data exist from other areas of The Bahamas. This study used fisheries-independent drumline captures, satellite telemetry, and bulk stable isotope analysis to advance our understanding of the residency, space use, and trophic role of great hammerheads in Andros, the largest island in The Bahamas. We examined movement behaviors and thermal range within the Bahamian Exclusive Economic Zone, and constructed Bayesian mixing models based on carbon, nitrogen, and sulfur isotope ratios to estimate the importance of prey species in the diet of great hammerheads. Our data revealed year-round residency of Andros-caught great hammerheads in Bahamian waters with site-fidelity to and high use of habitats along the reef-drop off and flats of Andros. Great hammerheads predominantly fed on barracuda and small-bodied elasmobranchs in Andros connecting food webs from the pelagic zone to the shoreline. This study expands our knowledge of the ecology of great hammerheads in the northwestern Atlantic and shows that, despite their highly-mobile nature, some individuals reside in the Bahamas year round. These findings suggest the Bahamian shark sanctuary could be more than just a seasonal refuge for this species as previously proposed, and merit further research to assess the conservation value of the sanctuary towards regional rebuilding goals for greathammerheads.https://www.frontiersin.org/articles/10.3389/fmars.2025.1544482/fullelasmobranchsmart position and temperature tagsmanagement stocktrophic flexibilitydynamic brownian bridge movement modelK-means
spellingShingle T. L. Guttridge
V. Heim
S. Dedman
S. Dedman
A. E. Guttridge
S. A. Bain
B. A. Keller
B. A. Keller
P. Matich
Stay or go? Space and resource use of the great hammerhead (Sphyrna mokarran) off Andros Island, The Bahamas
Frontiers in Marine Science
elasmobranch
smart position and temperature tags
management stock
trophic flexibility
dynamic brownian bridge movement model
K-means
title Stay or go? Space and resource use of the great hammerhead (Sphyrna mokarran) off Andros Island, The Bahamas
title_full Stay or go? Space and resource use of the great hammerhead (Sphyrna mokarran) off Andros Island, The Bahamas
title_fullStr Stay or go? Space and resource use of the great hammerhead (Sphyrna mokarran) off Andros Island, The Bahamas
title_full_unstemmed Stay or go? Space and resource use of the great hammerhead (Sphyrna mokarran) off Andros Island, The Bahamas
title_short Stay or go? Space and resource use of the great hammerhead (Sphyrna mokarran) off Andros Island, The Bahamas
title_sort stay or go space and resource use of the great hammerhead sphyrna mokarran off andros island the bahamas
topic elasmobranch
smart position and temperature tags
management stock
trophic flexibility
dynamic brownian bridge movement model
K-means
url https://www.frontiersin.org/articles/10.3389/fmars.2025.1544482/full
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