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

Frontiers in Marine Science, Journal Year: 2025, Volume and Issue: 12

Published: March 21, 2025

In light of global declines upper-level marine predators, such as the great hammerhead, ( Sphyrna mokarran) a thorough understanding their behavioral ecology is needed for designing effective management strategies to preserve key role in maintaining ecosystem functioning, stability, and resilience. Within northwestern Atlantic, hammerheads display regional connectivity between U.S. East Coast western edge The Bahamas, but despite suggested importance Bahamian shark sanctuary towards population recovery strategies, relatively few data exist from other areas Bahamas. This study used fisheries-independent drumline captures, satellite telemetry, bulk stable isotope analysis advance our residency, space use, trophic Andros, largest island We examined movement behaviors thermal range within Exclusive Economic Zone, constructed Bayesian mixing models based on carbon, nitrogen, sulfur ratios estimate prey species diet hammerheads. Our revealed year-round residency Andros-caught waters with site-fidelity high use habitats along reef-drop off flats Andros. Great predominantly fed barracuda small-bodied elasmobranchs Andros connecting food webs pelagic zone shoreline. expands knowledge Atlantic shows that, highly-mobile nature, some individuals reside Bahamas year round. These findings suggest could be more than just seasonal refuge this previously proposed, merit further research assess conservation value rebuilding goals greathammerheads.

Language: Английский

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Migratory patterns and seasonal habitat use of great hammerhead sharks (Sphyrna mokarran) in the southeastern United States

Journal of Fish Biology, Journal Year: 2025, Volume and Issue: unknown

Published: April 3, 2025

The great hammerhead shark (Sphyrna mokarran) is a highly mobile species whose population in the United States declined dramatically through early 2000s. Their spatial ecology poorly understood, creating challenges for effective conservation of this enigmatic marine predator. Using acoustic telemetry and network analyses, we describe movement patterns 15 mature sharks (207-331.5 cm fork length) primarily within waters southeastern from April 2019 to December 2022, including identifying corridors, core use areas seasonal shifts habitat use. Great hammerheads exhibited partial migration; some undertook consistent, repeatable, round-trip migrations between tagging site Florida Keys northern points Gulf Mexico Atlantic coast. Conversely, others remained year-round. Network analysis coupled with community detection algorithms revealed that individual displayed oceanic basin affinity, favouring migration either Ocean or Mexico. shifted their seasonally inshore channels (spring summer) offshore artificial reefs natural reef tract (summer winter). These may be driven by prey availability, as often corresponded known locations spawning aggregations fish. data fill an important knowledge gap migratory can improve management strategies historically overexploited species. We discuss importance drawing upon multiple management, particularly designation essential fish habitat.

Language: Английский

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From little things big things grow: enhancement of an acoustic telemetry network to monitor broad-scale movements of marine species along Australia’s east coast

Movement Ecology, Journal Year: 2024, Volume and Issue: 12(1)

Published: April 23, 2024

Abstract Background Acoustic telemetry has become a fundamental tool to monitor the movement of aquatic species. Advances in technology, particular development batteries with lives > 10 years, have increased our ability track long-term patterns many However, logistics and financial constraints often dictate locations deployment duration acoustic receivers. Consequently, there is compromise between optimal array design affordability. Such can hinder marine animals over large spatial temporal scales. Continental-scale receiver networks study large-scale movements, but significant gaps coverage remain. Methods Since 2007, Integrated Marine Observing System’s Animal Tracking Facility (IMOS ATF) maintained permanent installations on eastern Australian seaboard. In this study, we present recent enhancement IMOS ATF tracking infrastructure Queensland collect data movements species northeast extent national array. Securing relatively small initial investment for expanding tagging activities served as catalyst, bringing together diverse group stakeholders (research institutes, universities, government departments, port corporations, industries, Indigenous ranger groups tourism operators) create an extensive collaborative network that could sustain extended into future. To fill existing maximise monitoring footprint, new initiative atypical design, deploying single receivers spread across 2,100 km waters. Results The approach revealed previously unknown broad-scale some highlights clusters are not always required enhance collection. designs using predominantly deployments more vulnerable when lost or fail, therefore “redundancy” critical consideration designing type Conclusion Initial results suggest enhancement, if sustained will uncover range assist addressing ecological, fisheries, conservation questions multiple

Language: Английский

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Resource use of Sphyrna mokarran and S. lewini (Chondrichthyes) neonates and juveniles in the western Arabian Gulf: a stable isotope analysis

Endangered Species Research, Journal Year: 2024, Volume and Issue: 54, P. 277 - 284

Published: May 27, 2024

The great hammerhead shark Sphyrna mokarran and the scalloped S. lewini are marine top predators with global distributions. However, limited information is available on trophic ecology of sharks in Indian Ocean. In this study, we measured stable nitrogen carbon isotopes muscle tissues neonates juveniles from waters western Arabian Gulf. general, values δ 15 N were lower (10.8-18.7‰) than (12.2-18.7‰), indicating a reliance food sources low values. Isotopic niche similarities observed between female male . We further considerable ontogenetic changes both (a reduction 19 to 12‰), reflecting maternal effect. effects total length sex isotope nonsignificant juveniles. Gulf likely serves as key feeding ground for By contrast, appears have level region.

Language: Английский

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