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A photogrammetric method to estimate total length of the largest mammal, the blue whale (Balaenoptera musculus). Mamm Biol 2022. [DOI: 10.1007/s42991-022-00307-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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2
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Ramos EA, Landeo-Yauri S, Castelblanco-Martínez N, Arreola MR, Quade AH, Rieucau G. Drone-based photogrammetry assessments of body size and body condition of Antillean manatees. Mamm Biol 2022. [DOI: 10.1007/s42991-022-00228-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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3
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Hardenstine RS, He S, Cochran JEM, Braun CD, Cagua EF, Pierce SJ, Prebble CEM, Rohner CA, Saenz‐Angudelo P, Sinclair‐Taylor TH, Skomal GB, Thorrold SR, Watts AM, Zakroff CJ, Berumen ML. Pieces in a global puzzle: Population genetics at two whale shark aggregations in the western Indian Ocean. Ecol Evol 2022; 12:e8492. [PMID: 35127024 PMCID: PMC8796955 DOI: 10.1002/ece3.8492] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Revised: 10/30/2021] [Accepted: 11/10/2021] [Indexed: 02/01/2023] Open
Abstract
The whale shark Rhincodon typus is found throughout the world's tropical and warm-temperate ocean basins. Despite their broad physical distribution, research on the species has been concentrated at a few aggregation sites. Comparing DNA sequences from sharks at different sites can provide a demographically neutral understanding of the whale shark's global ecology. Here, we created genetic profiles for 84 whale sharks from the Saudi Arabian Red Sea and 72 individuals from the coast of Tanzania using a combination of microsatellite and mitochondrial sequences. These two sites, separated by approximately 4500 km (shortest over-water distance), exhibit markedly different population demographics and behavioral ecologies. Eleven microsatellite DNA markers revealed that the two aggregation sites have similar levels of allelic richness and appear to be derived from the same source population. We sequenced the mitochondrial control region to produce multiple global haplotype networks (based on different alignment methodologies) that were broadly similar to each other in terms of population structure but suggested different demographic histories. Data from both microsatellite and mitochondrial markers demonstrated the stability of genetic diversity within the Saudi Arabian aggregation site throughout the sampling period. These results contrast previously measured declines in diversity at Ningaloo Reef, Western Australia. Mapping the geographic distribution of whale shark lineages provides insight into the species' connectivity and can be used to direct management efforts at both local and global scales. Similarly, understanding historical fluctuations in whale shark abundance provides a baseline by which to assess current trends. Continued development of new sequencing methods and the incorporation of genomic data could lead to considerable advances in the scientific understanding of whale shark population ecology and corresponding improvements to conservation policy.
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Affiliation(s)
- Royale S. Hardenstine
- Division of Biological and Environmental Science and EngineeringRed Sea Research CenterKing Abdullah University of Science and TechnologyThuwalSaudi Arabia
| | - Song He
- Division of Biological and Environmental Science and EngineeringRed Sea Research CenterKing Abdullah University of Science and TechnologyThuwalSaudi Arabia
| | - Jesse E. M. Cochran
- Division of Biological and Environmental Science and EngineeringRed Sea Research CenterKing Abdullah University of Science and TechnologyThuwalSaudi Arabia
| | - Camrin D. Braun
- Biology DepartmentWoods Hole Oceanographic InstitutionWoods HoleMassachusettsUSA
| | - Edgar Fernando Cagua
- School of Biological SciencesCentre for Integrative EcologyUniversity of CanterburyChristchurchNew Zealand
- WorldFishBayan LepasMalaysia
| | | | - Clare E. M. Prebble
- Marine Megafauna FoundationTruckeeCaliforniaUSA
- National Oceanography CentreUniversity of South HamptonSouth HamtonUK
| | | | - Pablo Saenz‐Angudelo
- Facultad de CienciasInstituo de Ciencias Ambientales y EvolutivasUniversidad Austral de ChileValdiviaChile
| | | | - Gregory B. Skomal
- Massachusetts Division of Marine FisheriesNew BedfordMassachusettsUSA
| | - Simon R. Thorrold
- Biology DepartmentWoods Hole Oceanographic InstitutionWoods HoleMassachusettsUSA
| | - Alexandra M. Watts
- Marine Megafauna FoundationTruckeeCaliforniaUSA
- Ecological Genetics and Conservation LaboratoryManchester Metropolitan UniversityManchesterUK
| | - Casey J. Zakroff
- Division of Biological and Environmental Science and EngineeringRed Sea Research CenterKing Abdullah University of Science and TechnologyThuwalSaudi Arabia
| | - Michael L. Berumen
- Division of Biological and Environmental Science and EngineeringRed Sea Research CenterKing Abdullah University of Science and TechnologyThuwalSaudi Arabia
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4
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Rohner CA, Venables SK, Cochran JEM, Prebble CEM, Kuguru BL, Berumen ML, Pierce SJ. The need for long-term population monitoring of the world’s largest fish. ENDANGER SPECIES RES 2022. [DOI: 10.3354/esr01177] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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5
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Araujo G, Legaspi CGM, Ferber S, Murray R, Burdett K, Grundy S, Labaja J, Snow S, Yaptinchay A, Ponzo A. In-water methods reveal population dynamics of a green turtle Chelonia mydas foraging aggregation in the Philippines. ENDANGER SPECIES RES 2019. [DOI: 10.3354/esr00989] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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6
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Araujo G, Agustines A, Tracey B, Snow S, Labaja J, Ponzo A. Photo-ID and telemetry highlight a global whale shark hotspot in Palawan, Philippines. Sci Rep 2019; 9:17209. [PMID: 31748588 PMCID: PMC6868279 DOI: 10.1038/s41598-019-53718-w] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Accepted: 11/05/2019] [Indexed: 02/07/2023] Open
Abstract
The Philippines is home to the second largest known population of whale sharks in the world. The species is listed as endangered due to continued population declines in the Indo-Pacific. Knowledge about the connectivity within Southeast Asia remains poor, and thus international management is difficult. Here, we employed pop-up archival tags, data mining and dedicated effort to understand an aggregation of whale sharks at Honda Bay, Palawan, Philippines, and its role in the species' conservation. Between Apr and Oct 2018, we conducted 159 surveys identifying 117 individual whale sharks through their unique spot patterns (96.5% male, mean 4.5 m). A further 66 individual whale sharks were identified from local operators, and data mined on social media platforms. The satellite telemetry data showed that the whale sharks moved broadly, with one individual moving to Sabah, Malaysia, before returning to the site <1 year later. Similarly, another tagged whale shark returned to the site at a similar periodicity after reaching the Malay-Filipino border. One individual whale shark first identified in East Kalimantan, Indonesia by a citizen scientist was resighted in Honda Bay ~3.5 years later. Honda Bay is a globally important site for the endangered whale shark with connectivity to two neighbouring countries, highlighting the need for international cooperation to manage the species.
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Affiliation(s)
- Gonzalo Araujo
- Large Marine Vertebrates Research Institute Philippines, Cagulada Compound, Jagna, 6308, Bohol, Philippines.
| | - Ariana Agustines
- Large Marine Vertebrates Research Institute Philippines, Cagulada Compound, Jagna, 6308, Bohol, Philippines
| | - Brian Tracey
- Large Marine Vertebrates Research Institute Philippines, Cagulada Compound, Jagna, 6308, Bohol, Philippines
| | - Sally Snow
- Large Marine Vertebrates Research Institute Philippines, Cagulada Compound, Jagna, 6308, Bohol, Philippines
| | - Jessica Labaja
- Large Marine Vertebrates Research Institute Philippines, Cagulada Compound, Jagna, 6308, Bohol, Philippines
| | - Alessandro Ponzo
- Large Marine Vertebrates Research Institute Philippines, Cagulada Compound, Jagna, 6308, Bohol, Philippines
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7
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Cochran JEM, Braun CD, Cagua EF, Campbell MF, Hardenstine RS, Kattan A, Priest MA, Sinclair-Taylor TH, Skomal GB, Sultan S, Sun L, Thorrold SR, Berumen ML. Multi-method assessment of whale shark (Rhincodon typus) residency, distribution, and dispersal behavior at an aggregation site in the Red Sea. PLoS One 2019; 14:e0222285. [PMID: 31498848 PMCID: PMC6733483 DOI: 10.1371/journal.pone.0222285] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2019] [Accepted: 08/25/2019] [Indexed: 11/29/2022] Open
Abstract
Whale sharks (Rhincodon typus) are typically dispersed throughout their circumtropical range, but the species is also known to aggregate in specific coastal areas. Accurate site descriptions associated with these aggregations are essential for the conservation of R. typus, an Endangered species. Although aggregations have become valuable hubs for research, most site descriptions rely heavily on sightings data. In the present study, visual census, passive acoustic monitoring, and long range satellite telemetry were combined to track the movements of R. typus from Shib Habil, a reef-associated aggregation site in the Red Sea. An array of 63 receiver stations was used to record the presence of 84 acoustically tagged sharks (35 females, 37 males, 12 undetermined) from April 2010 to May 2016. Over the same period, identification photos were taken for 76 of these tagged individuals and 38 were fitted with satellite transmitters. In total of 37,461 acoustic detections, 210 visual encounters, and 33 satellite tracks were analyzed to describe the sharks’ movement ecology. The results demonstrate that the aggregation is seasonal, mostly concentrated on the exposed side of Shib Habil, and seems to attract sharks of both sexes in roughly equal numbers. The combined methodologies also tracked 15 interannual homing-migrations, demonstrating that many sharks leave the area before returning in later years. When compared to acoustic studies from other aggregations, these results demonstrate that R. typus exhibits diverse, site-specific ecologies across its range. Sightings-independent data from acoustic telemetry and other sources are an effective means of validating more common visual surveys.
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Affiliation(s)
- Jesse E. M. Cochran
- Red Sea Research Center, Division of Biological and Environmental Science and Engineering, King Abdullah University of Science and Technology, Thuwal, Kingdom of Saudi Arabia
- * E-mail:
| | - Camrin D. Braun
- Massachusetts Institute of Technology–Woods Hole Oceanographic Institution Joint Program in Oceanography/Applied Ocean Science and Engineering, Cambridge, MA, United States of America
- Biology Department, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts, United States of America
| | - E. Fernando Cagua
- Centre for Integrative Ecology, School of Biological Sciences, University of Canterbury, Private Bag, Christchurch, New Zealand
| | - Michael F. Campbell
- Red Sea Research Center, Division of Biological and Environmental Science and Engineering, King Abdullah University of Science and Technology, Thuwal, Kingdom of Saudi Arabia
| | - Royale S. Hardenstine
- Red Sea Research Center, Division of Biological and Environmental Science and Engineering, King Abdullah University of Science and Technology, Thuwal, Kingdom of Saudi Arabia
| | - Alexander Kattan
- Red Sea Research Center, Division of Biological and Environmental Science and Engineering, King Abdullah University of Science and Technology, Thuwal, Kingdom of Saudi Arabia
| | - Mark A. Priest
- Marine Spatial Ecology Lab, School of Biological Sciences, University of Queensland, St. Lucia, Queensland, Australia
| | - Tane H. Sinclair-Taylor
- Red Sea Research Center, Division of Biological and Environmental Science and Engineering, King Abdullah University of Science and Technology, Thuwal, Kingdom of Saudi Arabia
| | - Gregory B. Skomal
- Massachusetts Division of Marine Fisheries, New Bedford, MA, United States of America
| | - Sahar Sultan
- Red Sea Research Center, Division of Biological and Environmental Science and Engineering, King Abdullah University of Science and Technology, Thuwal, Kingdom of Saudi Arabia
- School of Biology, University of St Andrews, St Andrews, Scotland, United Kingdom
| | - Lu Sun
- Red Sea Research Center, Division of Biological and Environmental Science and Engineering, King Abdullah University of Science and Technology, Thuwal, Kingdom of Saudi Arabia
- Key Laboratory of Science and Engineering for Marine Ecology and Environment, First Institute of Oceanography, Ministry of Natural Resources, Qingdao, China
| | - Simon R. Thorrold
- Biology Department, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts, United States of America
| | - Michael L. Berumen
- Red Sea Research Center, Division of Biological and Environmental Science and Engineering, King Abdullah University of Science and Technology, Thuwal, Kingdom of Saudi Arabia
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8
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van Aswegen M, Christiansen F, Symons J, Mann J, Nicholson K, Sprogis K, Bejder L. Morphological differences between coastal bottlenose dolphin (Tursiops aduncus) populations identified using non-invasive stereo-laser photogrammetry. Sci Rep 2019; 9:12235. [PMID: 31439909 PMCID: PMC6706378 DOI: 10.1038/s41598-019-48419-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Accepted: 08/05/2019] [Indexed: 02/06/2023] Open
Abstract
Obtaining morphometric data on free-ranging marine megafauna is difficult, as traditional methods rely on post-mortem or live-capture techniques. We linked stereo-laser photogrammetry with long-term demographic data to compare length-at-age (LaA) growth curves of two well-studied populations of Indo-Pacific bottlenose dolphins (Tursiops aduncus) in south-western (SW) and Shark Bay (SB), mid-western Australia. First, we determined the relationship between total length (TL) and blowhole-to-dorsal fin (BH-DF) length from post-mortem subjects (R2 = 0.99, n = 12). We then predicted TL from laser-derived BH-DF measurements of 129 and 74 known-age individuals in SW and SB, respectively. Richards growth models best described our LaA data. While birth length (103-110 cm) was similar between study regions, TL estimates at 1, 3, 12, and 25 years differed significantly (p < 0.001). Asymptotic length of adult males (SW = 246 cm, SB = 201 cm) and females (SW = 244 cm, SB = 200 cm) also differed significantly. Morphotypic variations likely reflect regional adaptations to local water temperatures, with the temperate SW having cooler waters than sub-tropical SB. We demonstrate the effectiveness of a non-invasive technique to understand ecological, demographic and life-history characteristics of long-lived marine megafauna, which are critical parameters for informing conservation and management actions.
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Affiliation(s)
- Martin van Aswegen
- Environmental and Conservation Sciences, Murdoch University, South Street, Murdoch, WA, 6150, Australia. .,Aquatic Megafauna Research Unit, Harry Butler Institute, Murdoch University, South Street, Murdoch, WA, 6150, Australia. .,Marine Mammal Research Program, Hawaii Institute of Marine Biology, University of Hawaii at Manoa, 96744, Kaneohe, USA.
| | - Fredrik Christiansen
- Environmental and Conservation Sciences, Murdoch University, South Street, Murdoch, WA, 6150, Australia.,Aquatic Megafauna Research Unit, Harry Butler Institute, Murdoch University, South Street, Murdoch, WA, 6150, Australia.,Aarhus Institute of Advanced Studies, Høegh-Guldbergs Gade 6B, 8000, Aarhus, Denmark.,Zoophysiology, Department of Bioscience, Aarhus University, 8000, Aarhus, Denmark
| | - John Symons
- Environmental and Conservation Sciences, Murdoch University, South Street, Murdoch, WA, 6150, Australia.,Aquatic Megafauna Research Unit, Harry Butler Institute, Murdoch University, South Street, Murdoch, WA, 6150, Australia
| | - Janet Mann
- Department of Biology and Department of Psychology, Georgetown University, 20057, Washington, DC, USA
| | - Krista Nicholson
- Environmental and Conservation Sciences, Murdoch University, South Street, Murdoch, WA, 6150, Australia.,Aquatic Megafauna Research Unit, Harry Butler Institute, Murdoch University, South Street, Murdoch, WA, 6150, Australia
| | - Kate Sprogis
- Environmental and Conservation Sciences, Murdoch University, South Street, Murdoch, WA, 6150, Australia.,Aquatic Megafauna Research Unit, Harry Butler Institute, Murdoch University, South Street, Murdoch, WA, 6150, Australia.,Zoophysiology, Department of Bioscience, Aarhus University, 8000, Aarhus, Denmark
| | - Lars Bejder
- Environmental and Conservation Sciences, Murdoch University, South Street, Murdoch, WA, 6150, Australia.,Aquatic Megafauna Research Unit, Harry Butler Institute, Murdoch University, South Street, Murdoch, WA, 6150, Australia.,Marine Mammal Research Program, Hawaii Institute of Marine Biology, University of Hawaii at Manoa, 96744, Kaneohe, USA
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9
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Trobbiani GA, Irigoyen A, Venerus LA, Fiorda PM, Parma AM. A low-cost towed video camera system for underwater surveys: comparative performance with standard methodology. ENVIRONMENTAL MONITORING AND ASSESSMENT 2018; 190:683. [PMID: 30374778 DOI: 10.1007/s10661-018-7070-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2018] [Accepted: 10/22/2018] [Indexed: 06/08/2023]
Abstract
Technological advances in the field of underwater video have led to an exponential increase in the use of drifting cameras (DC) and remotely operated vehicles (ROVs) to monitor the diversity, abundance, and size structure of marine life. Main advantages of DCs relative to ROVs are their lower costs and the much simpler logistics required to operate them. This study compares the performance of a new low-cost DC system equipped with a novel measuring device with that of a standard DC bearing an array of laser pointers. The new DC, which can be operated from a small boat, carries a pair of parallel steel "whiskers" that are dragged on the seabed within the field of view of the camera, providing a scale for measuring and estimating the density of benthic biota. An experiment conducted using an array of objects of known sizes laid on the bottom showed that its performance in terms of both size and density estimation was similar to that of the standard technique based on laser pointers. Measurement errors had a negligible negative bias (- 2.3%) and a standard deviation that ranged between 13 and 8% for objects from 25 to 110 mm in size. The whiskers offered a simplified method for density estimation that avoids the need to calculate the width of the field of view, thus reducing the video processing time by around 60% with respect to the standard method. Briefly, the new system offers an efficient low-cost alternative for benthic ecology studies conducted on soft or non-irregular bottoms.
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Affiliation(s)
- G A Trobbiani
- Centro para el Estudio de Sistemas Marinos (CESIMAR), Consejo Nacional de Investigaciones Científicas y Técnicas (CCT CONICET - CENPAT), Boulevard Brown 2915, (U9120ACD), Puerto Madryn, Chubut, Argentina.
| | - A Irigoyen
- Centro para el Estudio de Sistemas Marinos (CESIMAR), Consejo Nacional de Investigaciones Científicas y Técnicas (CCT CONICET - CENPAT), Boulevard Brown 2915, (U9120ACD), Puerto Madryn, Chubut, Argentina
| | - L A Venerus
- Centro para el Estudio de Sistemas Marinos (CESIMAR), Consejo Nacional de Investigaciones Científicas y Técnicas (CCT CONICET - CENPAT), Boulevard Brown 2915, (U9120ACD), Puerto Madryn, Chubut, Argentina
| | - P M Fiorda
- Centro para el Estudio de Sistemas Marinos (CESIMAR), Consejo Nacional de Investigaciones Científicas y Técnicas (CCT CONICET - CENPAT), Boulevard Brown 2915, (U9120ACD), Puerto Madryn, Chubut, Argentina
| | - A M Parma
- Centro para el Estudio de Sistemas Marinos (CESIMAR), Consejo Nacional de Investigaciones Científicas y Técnicas (CCT CONICET - CENPAT), Boulevard Brown 2915, (U9120ACD), Puerto Madryn, Chubut, Argentina
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10
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Diamant S, Rohner CA, Kiszka JJ, Guillemain d’Echon A, Guillemain d’Echon T, Sourisseau E, Pierce SJ. Movements and habitat use of satellite-tagged whale sharks off western Madagascar. ENDANGER SPECIES RES 2018. [DOI: 10.3354/esr00889] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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11
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Rohner CA, Richardson AJ, Jaine FRA, Bennett MB, Weeks SJ, Cliff G, Robinson DP, Reeve-Arnold KE, Pierce SJ. Satellite tagging highlights the importance of productive Mozambican coastal waters to the ecology and conservation of whale sharks. PeerJ 2018; 6:e4161. [PMID: 29312815 PMCID: PMC5755488 DOI: 10.7717/peerj.4161] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Accepted: 11/23/2017] [Indexed: 11/25/2022] Open
Abstract
The whale shark Rhincodon typus is an endangered, highly migratory species with a wide, albeit patchy, distribution through tropical oceans. Ten aerial survey flights along the southern Mozambican coast, conducted between 2004–2008, documented a relatively high density of whale sharks along a 200 km stretch of the Inhambane Province, with a pronounced hotspot adjacent to Praia do Tofo. To examine the residency and movement of whale sharks in coastal areas around Praia do Tofo, where they may be more susceptible to gill net entanglement, we tagged 15 juveniles with SPOT5 satellite tags and tracked them for 2–88 days (mean = 27 days) as they dispersed from this area. Sharks travelled between 10 and 2,737 km (mean = 738 km) at a mean horizontal speed of 28 ± 17.1 SD km day−1. While several individuals left shelf waters and travelled across international boundaries, most sharks stayed in Mozambican coastal waters over the tracking period. We tested for whale shark habitat preferences, using sea surface temperature, chlorophyll-a concentration and water depth as variables, by computing 100 random model tracks for each real shark based on their empirical movement characteristics. Whale sharks spent significantly more time in cooler, shallower water with higher chlorophyll-a concentrations than model sharks, suggesting that feeding in productive coastal waters is an important driver of their movements. To investigate what this coastal habitat choice means for their conservation in Mozambique, we mapped gill nets during two dedicated aerial surveys along the Inhambane coast and counted gill nets in 1,323 boat-based surveys near Praia do Tofo. Our results show that, while whale sharks are capable of long-distance oceanic movements, they can spend a disproportionate amount of time in specific areas, such as along the southern Mozambique coast. The increasing use of drifting gill nets in this coastal hotspot for whale sharks is likely to be a threat to regional populations of this iconic species.
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Affiliation(s)
- Christoph A Rohner
- Manta Ray & Whale Shark Research Centre, Marine Megafauna Foundation, Praia do Tofo, Mozambique
| | - Anthony J Richardson
- CSIRO Oceans and Atmosphere, Dutton Park, QLD, Australia.,Centre for Applications in Natural Resource Mathematics (CARM), School of Mathematics and Physics, The University of Queensland, St Lucia, QLD, Australia
| | - Fabrice R A Jaine
- Manta Ray & Whale Shark Research Centre, Marine Megafauna Foundation, Praia do Tofo, Mozambique.,Sydney Institute of Marine Science, Mosman, NSW, Australia.,Department of Biological Sciences, Macquarie University, North Ryde, NSW, Australia
| | - Michael B Bennett
- School of Biomedical Sciences, The University of Queensland, St Lucia, QLD, Australia
| | - Scarla J Weeks
- Biophysical Oceanography Group, School of Geography, Planning and Environmental Management, The University of Queensland, St Lucia, QLD, Australia
| | - Geremy Cliff
- Kwa-Zulu Natal Sharks Board, Umhlanga, KZN, South Africa.,Biomedical Resource Unit, University of KwaZulu-Natal, Durban, KZN, South Africa
| | | | | | - Simon J Pierce
- Manta Ray & Whale Shark Research Centre, Marine Megafauna Foundation, Praia do Tofo, Mozambique
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12
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Rogers TD, Cambiè G, Kaiser MJ. Determination of size, sex and maturity stage of free swimming catsharks using laser photogrammetry. MARINE BIOLOGY 2017; 164:213. [PMID: 29104316 PMCID: PMC5651705 DOI: 10.1007/s00227-017-3241-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/03/2017] [Accepted: 10/04/2017] [Indexed: 06/07/2023]
Abstract
The lack of detailed life history (LH) information (e.g. age, growth, size at maturity, sex composition etc.) for many species of conservation importance limits the implementation of appropriate conservation measures. Typically, LH information is acquired using lethal sampling techniques, which undermines the goal of conservation. This is particularly problematic for many shark species that have low fecundity and slow growth rates. Here we tested the use of non-invasive laser photogrammetry to measure body morphometry in vivo. We used random forest classification models to identify allometric relationships (ratios between body measurements) that discriminated between the sex and stage of sexual maturity of Scyliorhinus canicula. We coupled the use of allometric ratios (determined from cadavers) with parallel laser photogrammetry, in order to collect total length (TL) and finer scale morphometrics from 37 free-swimming individuals. TL measurements proved to be accurate (SE = 5.2%) and precise (CV = 1.8%), and did not differ significantly from the known TL of the respective animal (t36 = 0.7, P = 0.5). Conditional Inference tree model predictions of free-swimming sharks correctly predicted 100% of mature males and 79% of immature males. Our results suggest that when used together, allometric ratios and parallel laser photogrammetry have the potential to be a promising alternative to collect essential life history information from free swimming animals and avoids the need for destructive sampling.
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Affiliation(s)
- Toby D. Rogers
- School of Ocean Sciences, Bangor University, Anglesey, LL59 5AB UK
| | - Giulia Cambiè
- School of Ocean Sciences, Bangor University, Anglesey, LL59 5AB UK
- Centre for Environment Fisheries and Aquaculture Science (CEFAS), Lowestoft, Suffolk NR33 0HT UK
| | - Michel J. Kaiser
- School of Ocean Sciences, Bangor University, Anglesey, LL59 5AB UK
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13
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Ramírez-Macías D, Queiroz N, Pierce SJ, Humphries NE, Sims DW, Brunnschweiler JM. Oceanic adults, coastal juveniles: tracking the habitat use of whale sharks off the Pacific coast of Mexico. PeerJ 2017; 5:e3271. [PMID: 28484673 PMCID: PMC5420197 DOI: 10.7717/peerj.3271] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2015] [Accepted: 04/04/2017] [Indexed: 11/23/2022] Open
Abstract
Eight whale sharks tagged with pop-up satellite archival tags off the Gulf of California, Mexico, were tracked for periods of 14–134 days. Five of these sharks were adults, with four females visually assessed to be pregnant. At least for the periods they were tracked, juveniles remained in the Gulf of California while adults moved offshore into the eastern Pacific Ocean. We propose that parturition occurs in these offshore waters. Excluding two juveniles that remained in the shallow tagging area for the duration of tracking, all sharks spent 65 ± 20.7% (SD) of their time near the surface, even over deep water, often in association with frontal zones characterized by cool-water upwelling. While these six sharks all made dives into the meso- or bathypelagic zones, with two sharks reaching the maximum depth recordable by the tags (1285.8 m), time spent at these depths represented a small proportion of the overall tracks. Most deep dives (72.7%) took place during the day, particularly during the early morning and late afternoon. Pronounced habitat differences by ontogenetic stage suggest that adult whale sharks are less likely to frequent coastal waters after the onset of maturity.
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Affiliation(s)
| | - Nuno Queiroz
- Centro de Investigação em Biodiversidade e Recursos Genéticos, Campus Agrário de Vairão, CIBIO/InBIO-Universidade do Porto, Porto, Portugal.,The Laboratory, Marine Biological Association of the United Kingdom, Plymouth, United Kingdom
| | | | - Nicolas E Humphries
- The Laboratory, Marine Biological Association of the United Kingdom, Plymouth, United Kingdom
| | - David W Sims
- The Laboratory, Marine Biological Association of the United Kingdom, Plymouth, United Kingdom.,Ocean and Earth Science, National Oceanography Centre Southampton, Waterfront Campus, University of Southampton, Southampton, United Kingdom.,Center for Biological Sciences, Highfield Campus, University of Southampton, Southampton, United Kingdom
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14
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Whale Shark (Rhincodon typus) Seasonal Occurrence, Abundance and Demographic Structure in the Mid-Equatorial Atlantic Ocean. PLoS One 2016; 11:e0164440. [PMID: 27783634 PMCID: PMC5082610 DOI: 10.1371/journal.pone.0164440] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Accepted: 09/26/2016] [Indexed: 11/28/2022] Open
Abstract
Whale sharks are generally associated with environmental factors that drive their movements to specific locations where food availability is high. Consequently, foraging is believed to be the main reason for the formation of whale shark aggregations. Feeding aggregations occur mainly in nearshore areas and are composed primarily of immature individuals. Conversely, aggregations of mature adults are rarely observed, and their occurrence is correlated with oceanic environments. Despite an increase in the number of whale shark studies, information on mating and parturition grounds is still lacking. In the present work, we assessed the ecological and behavioural aspects of the whale sharks that visit the archipelago of São Pedro and São Paulo (ASPSP), located ~1,000 km off the coast of Brazil in the equatorial Atlantic Ocean. Forty-nine whale sharks were recorded from February 2005 to May 2014. The estimated mean ± SD size was 8.27 ± 2.52 m (range: 2.5–14.0 m) with no significant differences in size across the year. The maturational stages were classified by size as immature (<8.0 m; 32.56%) and mature (>9.0 m; 46.51%); with almost half of the observed animals being mature specimens. The majority of sightings occurred between February and June. During this period, the ocean current weakens and the waters are enriched by eggs and larvae of fishes and invertebrates that attract marine life to forage. At the same time, evidence of reproductive activity in adult females (i.e. swollen abdomen and bite marks on the pectoral fins), and the potential mating behaviour exhibited by one male, suggest that the ASPSP area might also have a role in whale shark reproduction. Irrespective of its use for feeding or reproduction, this insular habitat serves as a meeting point for both juvenile and adult whale sharks, and may play an important ecological role for the species.
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Cochran JEM, Hardenstine RS, Braun CD, Skomal GB, Thorrold SR, Xu K, Genton MG, Berumen ML. Population structure of a whale shark Rhincodon typus aggregation in the Red Sea. JOURNAL OF FISH BIOLOGY 2016; 89:1570-1582. [PMID: 27401632 DOI: 10.1111/jfb.13054] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2015] [Accepted: 04/28/2016] [Indexed: 06/06/2023]
Abstract
The presence of whale sharks Rhincodon typus were recorded around Shib Habil, a small, coastal reef off the Red Sea coast of Saudi Arabia, from 2010 to 2015. A total of 267 suitable photographs resulting in the identification of 136 individuals, were documented from 305 encounters. Sharks were divided evenly between the sexes with no evidence of temporal or spatial segregation. All individuals were immature based on size estimates and, for males, juvenile clasper morphology. Scars were reported for 57% of R. typus with 15% showing evidence of propeller trauma. Estimates of population size and patterns of residency were calculated by modelling the lagged identification rate. Multiple models were run simultaneously and compared using the Akaike information criterion. An open population model was found to best represent the data and estimates a daily abundance between 15 and 34 R. typus during the aggregation season, with local residence times ranging from 4 to 44 days. Residence times away from Shib Habil range from 15 to 156 days with a permanent emigration-death rate between 0·07 and 0·58 individuals year(-1) . These results are broadly similar to those from other aggregations of R. typus, although the observed sexual parity and integration found at this site is unique for the species and needs further study.
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Affiliation(s)
- J E M Cochran
- Red Sea Research Centre, Division of Biological and Environmental Science and Engineering, King Abdullah University of Science and Technology, Thuwal, 23955, Kingdom of Saudi Arabia
| | - R S Hardenstine
- Red Sea Research Centre, Division of Biological and Environmental Science and Engineering, King Abdullah University of Science and Technology, Thuwal, 23955, Kingdom of Saudi Arabia
| | - C D Braun
- MIT-WHOI Joint Program in Oceanography, Woods Hole Oceanographic Institution, Woods Hole, MA, 02540, U.S.A
| | - G B Skomal
- Massachusetts Division of Marine Fisheries, New Bedford, MA, U.S.A
| | - S R Thorrold
- Biology Department, Woods Hole Oceanographic Institution, Woods Hole, MA, 02543, U.S.A
| | - K Xu
- Department of Management Science, University of Miami, Miami, FL, 33124, U.S.A
| | - M G Genton
- CEMSE Division, King Abdullah University of Science and Technology, Thuwal, 23955, Kingdom of Saudi Arabia
| | - M L Berumen
- Red Sea Research Centre, Division of Biological and Environmental Science and Engineering, King Abdullah University of Science and Technology, Thuwal, 23955, Kingdom of Saudi Arabia
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Robinson DP, Jaidah MY, Bach S, Lee K, Jabado RW, Rohner CA, March A, Caprodossi S, Henderson AC, Mair JM, Ormond R, Pierce SJ. Population Structure, Abundance and Movement of Whale Sharks in the Arabian Gulf and the Gulf of Oman. PLoS One 2016; 11:e0158593. [PMID: 27362839 PMCID: PMC4928964 DOI: 10.1371/journal.pone.0158593] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Accepted: 06/17/2016] [Indexed: 11/19/2022] Open
Abstract
Data on the occurrence of whale sharks, Rhincodon typus, in the Arabian Gulf and Gulf of Oman were collected by dedicated boat surveys and via a public-sightings scheme during the period from 2011 to 2014. A total of 422 individual whale sharks were photo-identified from the Arabian Gulf and the northern Gulf of Oman during that period. The majority of sharks (81%, n = 341) were encountered at the Al Shaheen area of Qatar, 90 km off the coast, with the Musandam region of Oman a secondary area of interest. At Al Shaheen, there were significantly more male sharks (n = 171) than females (n = 78; X2 = 17.52, P < 0.05). Mean estimated total length (TL) for sharks was 6.90 m ± 1.24 (median = 7 m; n = 296). Males (7.25 m ± 1.34; median = 8 m, n = 171) were larger than females (6.44 m ±1.09; median = 7 m, n = 78; Mann-Whitney U test, p < 0.01). Of the male sharks assessed for maturity 63% were mature (n = 81), with 50% attaining maturity by 7.29 m and 100% by 9.00 m. Two female sharks of >9 m individuals were visually assessed as pregnant. Connectivity among sharks sighted in Qatari, Omani and UAE waters was confirmed by individual spot pattern matches. A total of 13 identified sharks were re-sighted at locations other than that at which they were first sighted, including movements into and out of the Arabian Gulf through the Strait of Hormuz. Maximum likelihood techniques were used to model an estimated combined population for the Arabian Gulf and Gulf of Oman of 2837 sharks ± 1243.91 S.E. (95% C.I. 1720-6295). The Al Shaheen aggregation is thus the first site described as being dominated by mature males while the free-swimming pregnant females are the first reported from the Indian Ocean.
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Affiliation(s)
- David P. Robinson
- Heriot-Watt University, Edinburgh, United Kingdom
- Sharkwatch Arabia, Dubai, UAE
- * E-mail:
| | | | - Steffen Bach
- Maersk Oil Research and Technology Centre, Doha, Qatar
| | - Katie Lee
- Environment Department, University of York, York, United Kingdom
| | | | | | - Abi March
- Environment Department, University of York, York, United Kingdom
| | | | | | | | - Rupert Ormond
- Heriot-Watt University, Edinburgh, United Kingdom
- Marine Conservation International, Edinburgh, United Kingdom
| | - Simon J. Pierce
- Marine Megafauna Foundation, Truckee, CA, United States of America
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17
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Sequeira AMM, Thums M, Brooks K, Meekan MG. Error and bias in size estimates of whale sharks: implications for understanding demography. ROYAL SOCIETY OPEN SCIENCE 2016; 3:150668. [PMID: 27069656 PMCID: PMC4821267 DOI: 10.1098/rsos.150668] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2015] [Accepted: 02/18/2016] [Indexed: 05/30/2023]
Abstract
Body size and age at maturity are indicative of the vulnerability of a species to extinction. However, they are both difficult to estimate for large animals that cannot be restrained for measurement. For very large species such as whale sharks, body size is commonly estimated visually, potentially resulting in the addition of errors and bias. Here, we investigate the errors and bias associated with total lengths of whale sharks estimated visually by comparing them with measurements collected using a stereo-video camera system at Ningaloo Reef, Western Australia. Using linear mixed-effects models, we found that visual lengths were biased towards underestimation with increasing size of the shark. When using the stereo-video camera, the number of larger individuals that were possibly mature (or close to maturity) that were detected increased by approximately 10%. Mean lengths calculated by each method were, however, comparable (5.002 ± 1.194 and 6.128 ± 1.609 m, s.d.), confirming that the population at Ningaloo is mostly composed of immature sharks based on published lengths at maturity. We then collated data sets of total lengths sampled from aggregations of whale sharks worldwide between 1995 and 2013. Except for locations in the East Pacific where large females have been reported, these aggregations also largely consisted of juveniles (mean lengths less than 7 m). Sightings of the largest individuals were limited and occurred mostly prior to 2006. This result highlights the urgent need to locate and quantify the numbers of mature male and female whale sharks in order to ascertain the conservation status and ensure persistence of the species.
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Affiliation(s)
- Ana M. M. Sequeira
- IOMRC and The UWA Oceans Institute, School of Animal Biology and Centre for Marine Futures, University of Western Australia (M470), 35 Stirling Highway, Crawley, Western Australia 6009, Australia
| | - Michele Thums
- School of Civil, Environmental and Mining Engineering and UWA Oceans Institute, University of Western Australia (M470), 35 Stirling Highway, Crawley, Western Australia 6009, Australia
- Australian Institute of Marine Science, c/o UWA Oceans Institute (MO96), 35 Stirling Highway, Crawley, Western Australia 6009, Australia
| | - Kim Brooks
- Australian Institute of Marine Science, c/o UWA Oceans Institute (MO96), 35 Stirling Highway, Crawley, Western Australia 6009, Australia
| | - Mark G. Meekan
- Australian Institute of Marine Science, c/o UWA Oceans Institute (MO96), 35 Stirling Highway, Crawley, Western Australia 6009, Australia
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O'Connell CP, Leurs G. A minimally invasive technique to assess several life-history characteristics of the endangered great hammerhead shark Sphyrna mokarran. JOURNAL OF FISH BIOLOGY 2016; 88:1257-1264. [PMID: 26832609 DOI: 10.1111/jfb.12900] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2015] [Accepted: 12/17/2015] [Indexed: 06/05/2023]
Abstract
A dorsal-fin photo-identification technique paired with a non-invasive parallel laser photogrammetry technique was used to non-invasively identify individual Sphyrna mokarran over time. Based on the data collected over a duration of 59 days, 16 different S. mokarran (mean ± S.D. pre-caudal length: 220·82 ± 13·66 cm; mean ± S.D. cephalofoil width: 71·38 ± 7·94 cm) were identified using dorsal-fin photo-identification, with a mean ± S.D. shark re-sighting frequency of 4·05 ± 3·06 at-sea days. The results illustrate a high S. mokarran sighting rate and therefore, the utilization of parallel laser photogrammetry and dorsal-fin photo-identification may be a plausible multi-year approach to aid in non-invasively determining the growth rate and inter-annual site fidelity of these animals.
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Affiliation(s)
- C P O'Connell
- O'Seas Conservation Foundation, Inc., Yonkers, NY, 10701, U.S.A
| | - G Leurs
- Wageningen University and Research Centre, Wageningen, Netherlands
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