Insights into the Relative Abundance, Life History, and Ecology of Oceanic Sharks in the Eastern Bahamas

Brendan S. Talwar (), Edward J. Brooks, Debra L. Abercrombie, Brenda Anderson, Mark E. Bond, Annabelle M. L. Brooks, Demian D. Chapman, Gina M. Clementi, Candace Y. A. Fields, Jim Gelsleichter, R. Dean Grubbs, Lucy A. Howey, Lance K. B. Jordan, Jeremy J. Kiszka, Ryan J. Knotek, Yannis P. Papastamatiou, Cheston T. Peterson, Eric V. C. Schneider, Oliver N. Shipley, Sean Williams, Maggie M. Winchester and Michael R. Heithaus
Additional contact information
Brendan S. Talwar: Cape Eleuthera Institute, Rock Sound P.O. Box EL-26029, Bahamas
Edward J. Brooks: Cape Eleuthera Institute, Rock Sound P.O. Box EL-26029, Bahamas
Debra L. Abercrombie: Oceanic Whitetip Consortium, Ellicott City, MD 21042, USA
Brenda Anderson: Department of Biology, University of North Florida, Jacksonville, FL 32224, USA
Mark E. Bond: Department of Biological Sciences, Institute of Environment, Florida International University, North Miami, FL 33181, USA
Annabelle M. L. Brooks: Cape Eleuthera Institute, Rock Sound P.O. Box EL-26029, Bahamas
Demian D. Chapman: Department of Biological Sciences, Institute of Environment, Florida International University, North Miami, FL 33181, USA
Gina M. Clementi: Department of Biological Sciences, Institute of Environment, Florida International University, North Miami, FL 33181, USA
Candace Y. A. Fields: Cape Eleuthera Institute, Rock Sound P.O. Box EL-26029, Bahamas
Jim Gelsleichter: Department of Biology, University of North Florida, Jacksonville, FL 32224, USA
R. Dean Grubbs: Florida State University Coastal and Marine Laboratory, St. Teresa, FL 32358, USA
Lucy A. Howey: Oceanic Whitetip Consortium, Ellicott City, MD 21042, USA
Lance K. B. Jordan: Oceanic Whitetip Consortium, Ellicott City, MD 21042, USA
Jeremy J. Kiszka: Department of Biological Sciences, Institute of Environment, Florida International University, North Miami, FL 33181, USA
Ryan J. Knotek: Oceanic Whitetip Consortium, Ellicott City, MD 21042, USA
Yannis P. Papastamatiou: Department of Biological Sciences, Institute of Environment, Florida International University, North Miami, FL 33181, USA
Cheston T. Peterson: Florida State University Coastal and Marine Laboratory, St. Teresa, FL 32358, USA
Eric V. C. Schneider: Cape Eleuthera Institute, Rock Sound P.O. Box EL-26029, Bahamas
Oliver N. Shipley: Cape Eleuthera Institute, Rock Sound P.O. Box EL-26029, Bahamas
Sean Williams: Cape Eleuthera Institute, Rock Sound P.O. Box EL-26029, Bahamas
Maggie M. Winchester: Cape Eleuthera Institute, Rock Sound P.O. Box EL-26029, Bahamas
Michael R. Heithaus: Department of Biological Sciences, Institute of Environment, Florida International University, North Miami, FL 33181, USA

Sustainability, 2023, vol. 16, issue 1, 1-24

Abstract: Fisheries-independent data on the diversity, relative abundance, and demographic structure of poorly studied, threatened oceanic sharks are absent from much of the western North Atlantic Ocean, where multiple oceanic shark species have experienced significant population declines. Resource-limited management approaches require the identification of critical habitats or aggregation sites worthy of protection and enforcement. Data were collected on oceanic sharks using pelagic longline surveys, targeted baiting, and opportunistic encounters in oligotrophic open-ocean habitats of north-eastern Exuma Sound (NES), The Bahamas. The oceanic epipelagic shark community was also characterized using targeted baiting off Columbus Point, Cat Island (CI), a seamount north of San Salvador (SSSM), and the northwestern tip of Mayaguana. Pelagic longline surveys suggested that the relative abundance of sharks at NES was low (shark catch-per-unit-effort: 0.0007 sharks hook −1 h −1 ; 2.3 sharks per 1000 hooks). Silky sharks Carcharhinus falciformis , particularly juveniles (134 ± 39 cm stretched total length; mean ± SD STL), were the most common. Targeted baiting suggested oceanic whitetip sharks C. longimanus were abundant at CI, where large adults (245 ± 23 cm STL), most of which were females (83.8%, n = 98 of 117) that were gravid (65.7%; n = 46 of 70 assessed for pregnancy), dominated the aggregation. Many (20.5–26.5%, n = 24–31 of 117 depending on assumptions regarding tag loss) were recaptured or resighted at CI for up to five years. Silky sharks dominated catches at SSSM. Oceanic sharks, particularly adults, were sometimes caught or observed alongside short-finned pilot whales Globicephala macrorhynchus or tunas. Although The Bahamas offers threatened oceanic sharks refuge from fishing across its entire jurisdiction, these data suggest that some fixed features, including sites such as CI and potentially SSSM, are important aggregation sites with high regional conservation value and should be prioritized by fisheries managers and enforcement officials.

Keywords: oceanic sharks; oceanic whitetip shark; silky shark; open ocean; pelagic; The Bahamas (search for similar items in EconPapers)
JEL-codes: O13 Q Q0 Q2 Q3 Q5 Q56 (search for similar items in EconPapers)
Date: 2023
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