Spatial connectivity of reef manta rays across the Raja Ampat archipelago, Indonesia

Royal Society Open Science, Journal Year: 2024, Volume and Issue: 11(4)

Published: April 1, 2024

The reef manta ray Mobula alfredi is present throughout most island groups that form the Raja Ampat archipelago, Indonesia. species protected regionally and nationally currently managed as a single homogeneous population within 6.7 million ha archipelago. However, scientific evidence lacking regarding spatial connectivity structure of M. this Using network analysis an array 34 acoustic receivers deployed between February 2016 September 2021, we examined movements 72 subadult adult tagged in seven regions Ampat. A total 1094 were recorded primarily concentrated nearby receiver stations, highlighting frequent local within, limited long-distance regional arrays. Network revealed highly connected nodes acting hubs important for movements. community detection algorithm further indicated clusters network. Our results suggest existence metapopulation comprising three demographically geographically distinct subpopulations They also reveal importance Eagle Rock critical node movement network, justifying urgent inclusion site marine area

Language: Английский

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Current methods and best practice recommendations for skate and ray (Batoidea) research: capture, handling, anaesthesia, euthanasia, and tag attachment

Reviews in Fish Biology and Fisheries, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 28, 2025

Language: Английский

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Manta and devil ray aggregations: conservation challenges and developments in the field

Frontiers in Marine Science, Journal Year: 2023, Volume and Issue: 10

Published: April 17, 2023

Manta and devil rays (mobulids) are filter feeding elasmobranchs with extreme K-selective life histories found circumglobally from temperate to tropical waters. Their vulnerability fisheries exploitation, bycatch, boat collisions, entanglement unregulated tourism is exacerbated by their aggregative behavior. Studies have identified aggregation sites around the world for all nine mobulid species, these groupings varying a few individuals thousands. However, terminology used define aggregations drivers underpinning them remain unclear, hindering development of effective management conservation strategies. Here, we analyze behavior providing consistent definitions grouping events summarizing existing research on environmental factors triggering events. We find that behaviors facilitate socializing key history functions in mobulids, including feeding, courtship mating, predation avoidance, cleaning, thermoregulation. Conservation threats mitigation opportunities associated include fisheries, tourism, spatial protection, climate change. Finally, highlight knowledge gaps future prioritization developments field identification sites, study size demographics timing aggregations.

Language: Английский

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Closing the air gap: the use of drones for studying wildlife ecophysiology

Biological reviews/Biological reviews of the Cambridge Philosophical Society, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 17, 2025

ABSTRACT Techniques for non‐invasive sampling of ecophysiological data in wild animals have been developed response to challenges associated with studying captive or using invasive methods. Of these, drones, also known as Unoccupied Aerial Vehicles (UAVs), and their sensors, emerged a promising tool the ecophysiology toolkit. In this review, we synthesise research scoping review on use drones wildlife PRISMA‐SCr checklist identify where efforts focused knowledge gaps remain. We these results explore current best practices provide recommendations future use. 136 studies published since 2010, aided animal body condition morphometrics, kinematics biomechanics, bioenergetics, health (e.g. microbiomes, endocrinology, disease) both aquatic terrestrial environments. Focal taxa are biased towards marine mammals, particularly cetaceans. While conducted globally, is primarily led by institutions based North America, Oceania, Europe. The obtain morphometric through standard colour sensors single camera photogrammetry predominates. such video tracking thermal imaging allowed insights into other aspects ecophysiology, when combined external techniques biologgers. most used commercially available multirotor platforms modification collect samples, integration techniques, multidisciplinary integrate suite remote sensing methods more fully. outline how technological advances will play key role delivery novel improved data. recommend that researchers prepare influx drone‐assisted advancements cross‐institutional collaborations. describe diversify across species environments sources technologies comprehensive results.

Language: Английский

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Staying Close to Home: Horizontal Movements of Satellite-Tracked Reef Manta Rays Mobula alfredi (Krefft, 1868) in the World’s Largest Manta Sanctuary

Fishes, Journal Year: 2025, Volume and Issue: 10(2), P. 66 - 66

Published: Feb. 5, 2025

Indonesia is home to significant populations of globally vulnerable reef manta rays (Mobula alfredi) in at least four key regions: Berau, Nusa Penida, Komodo, and Raja Ampat. Despite detailed population studies each these regions, little known about their horizontal movement patterns. Our study used satellite telemetry investigate rays’ habitat use ranges. A total 33 were tagged with SPLASH10F-321A tags across the Berau (n = 5), Penida 8), Komodo 6), Ampat 14), yielding usable data from 25 tags. The tracked for 7 118 days (mean ± SD 50 30) July 2014 2022. results showed localized movements, strong residency near tagging sites, high site fidelity as evidenced by area-restricted search (ARS) behaviors frequent revisitations. Most restricted ranges region, no connectivity between regions. Across individuals, range (95% utilization distributions) varied significantly, ranging 19 48,294 km2 4667 10,354). These findings offer important insights into spatial patterns Indonesia, allowing formulation more effective management strategies.

Language: Английский

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Potential nursery area for the endangered oceanic manta ray in the Gulf of California, México

Environmental Biology of Fishes, Journal Year: 2025, Volume and Issue: unknown

Published: April 22, 2025

Language: Английский

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Preliminary insights into manta ray (Mobula alfredi and M. birostris) population demographics and distribution in South Africa

Environmental Biology of Fishes, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 8, 2025

Abstract Both the reef manta ray, Mobula alfredi and oceanic ray M. birostris , are repeatedly observed in South Africa, yet little is known about distributions of either species. In this study, we collated citizen science observations since 2003 to reveal six areas KwaZulu-Natal (KZN) Eastern Cape provinces, where rays have been sighted across multiple years. Using their unique ventral spot patterning, 184 individuals were photo-identified, comprising 139 45 . Most photo-identified encountered iSimangaliso Wetland Park (IWP) KZN (89%; n = 119) for Aliwal Shoal (48%; 22). We identified 32 new transboundary records 28 also photographed Inhambane Province, Mozambique, demonstrating connectivity, specifically Závora ( 27). One individual traveled times between IWP Závora, totaling 1305 km, another from Pondoland MPA a distance over 600 km. Further, extend southern range Africa by 500 km Mdumbi Beach Port Ngqura, Cape. These collective findings represent Africa’s first in-water assessment aggregations, showing particular be critical habitat movements documented here suggest population one most mobile globally. hope baseline data provided will drive increased research management along coastlines.

Language: Английский

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Genomic evidence indicates small island-resident populations and sex-biased behaviors of Hawaiian reef Manta Rays

BMC Ecology and Evolution, Journal Year: 2023, Volume and Issue: 23(1)

Published: July 8, 2023

Abstract Background Reef manta rays ( Mobula alfredi ) are globally distributed in tropical and subtropical seas. Their life history traits (slow growth, late maturity, low reproductive output) make them vulnerable to perturbations therefore require informed management strategies. Previous studies have reported wide-spread genetic connectivity along continental shelves suggesting high gene flow continuous habitats spanning hundreds of kilometers. However, the Hawaiian Islands, tagging photo-identification evidence suggest island populations isolated despite proximity, a hypothesis that has not yet been evaluated with data. Results This island-resident was tested by analyzing whole mitogenome haplotypes 2048 nuclear single nucleotide polymorphisms (SNPs) between M. (n = 38) on Hawaiʻi Island Maui Nui (the 4-island complex Maui, Molokaʻi, Lānaʻi Kahoʻolawe). Strong divergence Φ ST 0.488) relative genome-wide SNPs (neutral F 0.003; outlier 0.186), clustering mitochondrial among islands provides robust female reef strongly philopatric do migrate these two groups. Combined restricted male-mediated migration, equivalent male moving every 2.2 generations (~ 64 years), we provide significantly demographically isolated. Estimates contemporary effective population size N e 104 (95% CI: 99–110) 129 122–136) Nui. Conclusions Concordant from photo identification studies, results indicate small, genetically-isolated resident populations. We hypothesize due Mass Effect, large sufficient resources support populations, thereby making crossing deep channels separating groups unnecessary. Small size, diversity, k-selected region-specific anthropogenic threats, which include entanglement, boat strikes, habitat degradation. The long-term persistence Islands will island-specific

Language: Английский

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Reef manta ray social dynamics depend on individual differences in behaviour

Animal Behaviour, Journal Year: 2022, Volume and Issue: 191, P. 43 - 55

Published: July 15, 2022

Language: Английский

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Identifying spatial movements and residency of pelagic thresher sharks (Alopias pelagicus) using satellite and passive acoustic telemetry to inform local conservation in central Indonesia

Frontiers in Fish Science, Journal Year: 2024, Volume and Issue: 2

Published: May 22, 2024

The pelagic thresher shark ( Alopias pelagicus ) is globally endangered, threatened by bycatch, and targeted in industrial artisanal fisheries Indonesia. However, a lack of information about their ecology, particularly movement habitat use, hinders the development science-based conservation measures to protect species. Here, we report our research, which first use combination satellite passive acoustic telemetry investigate residency within Indonesia's waters, especially areas impacted local fisheries. A total 24 sharks were tagged with archival tags n = 9), internal 10), both 5) Selat Pantar Marine Protected Area (MPA). sharks, dominated females (71%) ranged size from 125–180 cm FL (mean ± SD: 161 13). Seven fifteen acoustically detected receivers, while twelve fourteen reported data. stayed attached for 81–181 days, tag detection periods 44–175 days. Horizontally, found satellite-tagged moved broadly, mainly offshore, approximately 90 km tagging locations. They between Banda, Flores, Savu Sea regions, where unregulated unreported longline gillnet are known operate. Meanwhile, showed distinct diel patterns around MPA's coastal indicating potential philopatric behavior. Vertically, spent significantly p < 0.001) more time deeper water during day shallower at night. deepest dive recorded was 1,889.5 m, ever Our results suggest that area-based protection can be an effective nearshore tool as individuals appear remain relatively restricted MPA extended periods. regulation aimed restricting illegal fishing also necessary when they move offshore. findings have been communicated relevant governments, resulting increased political will new legislation them connected waters East Nusa Tenggara.

Language: Английский

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