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Global collision-risk hotspots of marine traffic and the world's largest fish, the whale shark. Proc Natl Acad Sci U S A 2022; 119:e2117440119. [PMID: 35533277 PMCID: PMC9171791 DOI: 10.1073/pnas.2117440119] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Marine traffic is increasing globally yet collisions with endangered megafauna such as whales, sea turtles, and planktivorous sharks go largely undetected or unreported. Collisions leading to mortality can have population-level consequences for endangered species. Hence, identifying simultaneous space use of megafauna and shipping throughout ranges may reveal as-yet-unknown spatial targets requiring conservation. However, global studies tracking megafauna and shipping occurrences are lacking. Here we combine satellite-tracked movements of the whale shark, Rhincodon typus, and vessel activity to show that 92% of sharks’ horizontal space use and nearly 50% of vertical space use overlap with persistent large vessel (>300 gross tons) traffic. Collision-risk estimates correlated with reported whale shark mortality from ship strikes, indicating higher mortality in areas with greatest overlap. Hotspots of potential collision risk were evident in all major oceans, predominantly from overlap with cargo and tanker vessels, and were concentrated in gulf regions, where dense traffic co-occurred with seasonal shark movements. Nearly a third of whale shark hotspots overlapped with the highest collision-risk areas, with the last known locations of tracked sharks coinciding with busier shipping routes more often than expected. Depth-recording tags provided evidence for sinking, likely dead, whale sharks, suggesting substantial “cryptic” lethal ship strikes are possible, which could explain why whale shark population declines continue despite international protection and low fishing-induced mortality. Mitigation measures to reduce ship-strike risk should be considered to conserve this species and other ocean giants that are likely experiencing similar impacts from growing global vessel traffic.
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Harvey-Carroll J, Stewart JD, Carroll D, Mohamed B, Shameel I, Zareer IH, Araujo G, Rees R. The impact of injury on apparent survival of whale sharks (Rhincodon typus) in South Ari Atoll Marine Protected Area, Maldives. Sci Rep 2021; 11:937. [PMID: 33441580 PMCID: PMC7806644 DOI: 10.1038/s41598-020-79101-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Accepted: 12/04/2020] [Indexed: 01/29/2023] Open
Abstract
The whale shark (Rhincodon typus) is an endangered species with a declining global population. The South Ari Atoll Marine Protected Area (SAMPA), Maldives, is one of few locations globally where year-long residency of individuals occurs. This SAMPA aggregation appears to consist almost exclusively of immature males. Due to its year-round residency, this local aggregation is subjected to a high degree of tourism pressure. This ecotourism contributes to the high level of interest and protection offered to whale sharks by the local community. Unfortunately, if regulations are not followed or enforced, tourism can bring with it major stressors, such as accidental injuries. We used POPAN capture-mark-recapture models and lagged identification rate analysis to assess the effect of major injuries on whale shark residency within SAMPA. Injuries may be obtained outside SAMPA. We found individuals with major injuries had a higher apparent survival in the area than those without. Lagged identification rates also demonstrated that sharks with major injuries are more likely to return to the area. We suggest that major injuries result in sharks prolonging their time in the developmental habitat. These findings have implications for individual fitness and the population viability of this endangered species. We propose targeted conservation strategies be considered to protect sharks from further injury. Based on the presented spatio-temporal distributions of sharks, and current local knowledge of sighting patterns, speed limit zones and propeller-exclusion zones should be implemented and enforced. If carried out alongside tourist education, these measures will contribute to the protection of whale sharks within SAMPA and beyond. Furthermore, our results can aid research direction, alongside regulation and enforcement development, at similar sites worldwide.
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Affiliation(s)
- Jessica Harvey-Carroll
- Maldives Whale Shark Research Programme (MWSRP), South Ari Atoll, Maldives ,grid.11914.3c0000 0001 0721 1626School of Psychology and Neuroscience, University of St Andrews, St Andrews, UK
| | | | - Daire Carroll
- Maldives Whale Shark Research Programme (MWSRP), South Ari Atoll, Maldives ,grid.43641.340000 0001 1014 6626The James Hutton Institute, Dundee, UK ,grid.7372.10000 0000 8809 1613The University of Warwick, School of Life Science, Coventry, UK
| | - Basith Mohamed
- Maldives Whale Shark Research Programme (MWSRP), South Ari Atoll, Maldives
| | - Ibrahim Shameel
- Maldives Whale Shark Research Programme (MWSRP), South Ari Atoll, Maldives
| | | | - Gonzalo Araujo
- Large Marine Vertebrates Research Institute Philippines, Cagulada Compound, 6308 Jagna, Bohol Philippines
| | - Richard Rees
- Maldives Whale Shark Research Programme (MWSRP), South Ari Atoll, Maldives
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Womersley F, Hancock J, Perry CT, Rowat D. Wound-healing capabilities of whale sharks ( Rhincodon typus) and implications for conservation management. CONSERVATION PHYSIOLOGY 2021; 9:coaa120. [PMID: 33569175 PMCID: PMC7859907 DOI: 10.1093/conphys/coaa120] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2020] [Revised: 10/08/2020] [Accepted: 12/03/2020] [Indexed: 05/03/2023]
Abstract
Wound healing is important for marine taxa such as elasmobranchs, which can incur a range of natural and anthropogenic wounds throughout their life history. There is evidence that this group shows a high capacity for external wound healing. However, anthropogenic wounds may become more frequent due to increasing commercial and recreational marine activities. Whale sharks are particularly at risk of attaining injuries given their use of surface waters and wildlife tourism interest. There is limited understanding as to how whale sharks recover from injuries, and often insights are confined to singular opportunistic observations. The present study makes use of a unique and valuable photographic data source from two whale shark aggregation sites in the Indian Ocean. Successional injury-healing progression cases were reviewed to investigate the characteristics of injuries and quantify a coarse healing timeframe. Wounds were measured over time using an image standardization method. This work shows that by Day 25 major injury surface area decreased by an average of 56% and the most rapid healing case showed a surface area reduction of 50% in 4 days. All wounds reached a point of 90% surface area closure by Day 35. There were differences in healing rate based on wound type, with lacerations and abrasions taking 50 and 22 days to reach 90% healing, respectively. This study provides baseline information for wound healing in whale sharks and the methods proposed could act as a foundation for future research. Use of a detailed classification system, as presented here, may also assist in ocean scale injury comparisons between research groups and aid reliable descriptive data. Such findings can contribute to discussions regarding appropriate management in aggregation areas with an aim to reduce the likelihood of injuries, such as those resulting from vessel collisions, in these regions or during movements between coastal waters.
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Affiliation(s)
- Freya Womersley
- Marine Biological Association of the United Kingdom, The Laboratory, Citadel Hill, Plymouth, PL1 2PB, UK
- Ocean and Earth Science, National Oceanography Centre Southampton, University of Southampton, Southampton, SO17 1BJ, UK
- Marine Conservation Society Seychelles, Mahé, PO Box 384, Seychelles
- Corresponding author: Marine Biological Association of the United Kingdom, The Laboratory, Citadel Hill, Plymouth, PL1 2PB, UK.
| | - James Hancock
- Maldives Whale Shark Research Programme, Popeshead Court Offices, Peter Lane, York, Yorkshire, Y01 8SU, UK
| | - Cameron T Perry
- Maldives Whale Shark Research Programme, Popeshead Court Offices, Peter Lane, York, Yorkshire, Y01 8SU, UK
| | - David Rowat
- Marine Conservation Society Seychelles, Mahé, PO Box 384, Seychelles
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Legaspi C, Miranda J, Labaja J, Snow S, Ponzo A, Araujo G. In-water observations highlight the effects of provisioning on whale shark behaviour at the world's largest whale shark tourism destination. ROYAL SOCIETY OPEN SCIENCE 2020; 7:200392. [PMID: 33489251 PMCID: PMC7813242 DOI: 10.1098/rsos.200392] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Accepted: 11/30/2020] [Indexed: 05/11/2023]
Abstract
The whale shark is the world's largest fish that forms predictable aggregations across its range, many of which support tourism industries. The largest non-captive provisioned whale shark destination globally is at Oslob, Philippines, where more than 500 000 tourists visit yearly. There, the sharks are provisioned daily, year-round, allowing the human-shark interaction in nearshore waters. We used in-water behavioural observations of whale sharks between 2015 and 2017 to understand the relationship between external stimuli and shark behaviour, whether frequency of visits at the site can act as a predictor of behaviour, and the tourist compliance to the code of conduct. Mixed effects models revealed that the number of previous visits at the site was a strong predictor of whale shark behaviour, and that provisioned sharks were less likely to exhibit avoidance. Compliance was poor, with 93% of surveys having people less than 2 m from the animal, highlighting overcrowding of whale sharks at Oslob. Given the behavioural implications to whale sharks highlighted here and the local community's reliance on the tourism industry, it is imperative to improve management strategies to increase tourist compliance and strive for sustainable tourism practices.
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Affiliation(s)
- Christine Legaspi
- Large Marine Vertebrates Research Institute Philippines, Cagulada Compound, Brgy. Tejero, Jagna, Bohol 6308, Philippines
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Whitehead DA, Petatán Ramírez D, Olivier D, Gonzalez Armas R, Pancaldi F, Galvan-Magana F. Seasonal trends in whale shark Rhincodon typus sightings in an established tourism site in the Gulf of California, Mexico. JOURNAL OF FISH BIOLOGY 2019; 95:982-984. [PMID: 31338832 DOI: 10.1111/jfb.14106] [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: 05/16/2019] [Accepted: 07/22/2019] [Indexed: 06/10/2023]
Abstract
The number of individual whale shark Rhincodon typus sightings registered October 2015-March 2018 in Bahia de La Paz, Mexico, ranged from 73 to 129 animals per season (total 1662), with the majority of them identified as males. Density plot maps showed high correlations in sightings between sample seasons and revealed potential hotspot areas. Our study provides an essential baseline of information for the management of whale shark conservation and the associated touristic activities in the region.
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Affiliation(s)
- Darren Andrew Whitehead
- Centro Interdisciplinario de Ciencias Marinas, Instituto Politécnico Nacional, La Paz, México
| | - David Petatán Ramírez
- Universidad Autónoma de Baja California Sur. Departamento Académico de Biología Marina Carretera Transpeninsular, La Paz, México
| | - Damien Olivier
- Universidad Autónoma de Baja California Sur. Departamento Académico de Biología Marina Carretera Transpeninsular, La Paz, México
| | - Rogelio Gonzalez Armas
- Centro Interdisciplinario de Ciencias Marinas, Instituto Politécnico Nacional, La Paz, México
| | - Francesca Pancaldi
- Centro Interdisciplinario de Ciencias Marinas, Instituto Politécnico Nacional, La Paz, México
| | - Felipe Galvan-Magana
- Centro Interdisciplinario de Ciencias Marinas, Instituto Politécnico Nacional, La Paz, México
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Cisneros-Montemayor AM, Becerril-García EE, Berdeja-Zavala O, Ayala-Bocos A. Shark ecotourism in Mexico: Scientific research, conservation, and contribution to a Blue Economy. ADVANCES IN MARINE BIOLOGY 2019; 85:71-92. [PMID: 32456841 DOI: 10.1016/bs.amb.2019.08.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Shark ecotourism has the potential to contribute significantly to local and national economies and conservation, though this depends on a concerted effort to implement evidence-based management. Sharks are key attractions at some of the most important marine ecotourism sites throughout Mexico, focusing particularly on whale sharks, white sharks, hammerhead sharks, and several other reef-associated and pelagic species. This generates important employment opportunities and millions of USD in revenue, but truly implementing ecotourism requires that education and conservation be a part of activities and that these benefit local communities, so that the industry can be socially, economically and ecologically sustainable. In Mexico, this includes addressing potential negative impacts from vessel overcrowding, provisioning, inequitable distribution of ecotourism and conservation benefits and costs, and a broader lack of governance capacity to ensure that coastal development is environmentally sustainable and socially equitable. In the context of a Blue Economy centred on sustainability and local benefits, ecotourism provides a key incentive and opportunity to improve ocean management.
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Affiliation(s)
- A M Cisneros-Montemayor
- Nippon Foundation Nereus Program, Institute for the Oceans and Fisheries, The University of British Columbia, Vancouver, BC, Canada.
| | - E E Becerril-García
- Instituto Politécnico Nacional, Centro Interdisciplinario de Ciencias Marinas, La Paz, BCS, Mexico
| | - O Berdeja-Zavala
- Departamento Académico de Ciencias Marinas y Costeras, Universidad Autónoma de Baja California Sur, La Paz, BCS, Mexico
| | - A Ayala-Bocos
- Ecosistemas y Conservación: Proazul Terrestre A.C., Héroes de Independencia, La Paz, BCS, Mexico
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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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Thomson JA, Araujo G, Labaja J, McCoy E, Murray R, Ponzo A. Feeding the world's largest fish: highly variable whale shark residency patterns at a provisioning site in the Philippines. ROYAL SOCIETY OPEN SCIENCE 2017; 4:170394. [PMID: 28989750 PMCID: PMC5627090 DOI: 10.1098/rsos.170394] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Accepted: 08/30/2017] [Indexed: 05/25/2023]
Abstract
Provisioning wildlife for tourism is a controversial yet widespread practice. We analysed the residency patterns of juvenile whale sharks (Rhincodon typus) in Oslob, Philippines, where provisioning has facilitated a large shark-watching operation since 2011. We identified 208 individual sharks over three years, with an average of 18.6 (s.d. = 7.8, range = 6-43) individuals sighted per week. Weekly shark abundance varied seasonally and peak-season abundance (approx. May-November) increased across years. Whale sharks displayed diverse individual site visitation patterns ranging from a single visit to sporadic visits, seasonal residency and year-round residency. Nine individuals became year-round residents, which represents a clear response to provisioning. The timing of the seasonal peak at Oslob did not align with known non-provisioned seasonal aggregations elsewhere in the Philippines, which could suggest that seasonal residents at Oslob exploit this food source when prey availability at alternative sites is low. Since prolonged residency equates to less time foraging naturally, provisioning could influence foraging success, alter distributions and lead to dependency in later life stages. Such impacts must be carefully weighed against the benefits of provisioning (i.e. tourism revenue in a remote community) to facilitate informed management decisions.
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Affiliation(s)
- Jordan A. Thomson
- Large Marine Vertebrates Research Institute Philippines, Jagna, Bohol, Philippines
- Centre for Integrative Ecology, School of Life and Environmental Sciences, Deakin University, Warrnambool, Victoria 3280, Australia
| | - Gonzalo Araujo
- Large Marine Vertebrates Research Institute Philippines, Jagna, Bohol, Philippines
| | - Jessica Labaja
- Large Marine Vertebrates Research Institute Philippines, Jagna, Bohol, Philippines
| | - Emer McCoy
- Large Marine Vertebrates Research Institute Philippines, Jagna, Bohol, Philippines
| | - Ryan Murray
- Large Marine Vertebrates Research Institute Philippines, Jagna, Bohol, Philippines
| | - Alessandro Ponzo
- Large Marine Vertebrates Research Institute Philippines, Jagna, Bohol, Philippines
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Schleimer A, Araujo G, Penketh L, Heath A, McCoy E, Labaja J, Lucey A, Ponzo A. Learning from a provisioning site: code of conduct compliance and behaviour of whale sharks in Oslob, Cebu, Philippines. PeerJ 2015; 3:e1452. [PMID: 26644984 PMCID: PMC4671167 DOI: 10.7717/peerj.1452] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Accepted: 11/06/2015] [Indexed: 11/20/2022] Open
Abstract
While shark-based tourism is a rapidly growing global industry, there is ongoing controversy about the effects of provisioning on the target species. This study investigated the effect of feeding on whale sharks (Rhincodon typus) at a provisioning site in Oslob, Cebu, in terms of arrival time, avoidance and feeding behaviour using photo-identification and focal follows. Additionally, compliance to the code of conduct in place was monitored to assess tourism pressure on the whale sharks. Newly identified sharks gradually arrived earlier to the provisioning site after their initial sighting, indicating that the animals learn to associate the site with food rewards. Whale sharks with a long resighting history showed anticipatory behaviour and were recorded at the site on average 5 min after the arrival of feeder boats. Results from a generalised linear mixed model indicated that animals with a longer resighting history were less likely to show avoidance behaviour to touches or boat contact. Similarly, sequential data on feeding behaviour was modelled using a generalised estimating equations approach, which suggested that experienced whale sharks were more likely to display vertical feeding behaviour. It was proposed that the continuous source of food provides a strong incentive for the modification of behaviours, i.e., learning, through conditioning. Whale sharks are large opportunistic filter feeders in a mainly oligotrophic environment, where the ability to use novel food sources by modifying their behaviour could be of great advantage. Non-compliance to the code of conduct in terms of minimum distance to the shark (2 m) increased from 79% in 2012 to 97% in 2014, suggesting a high tourism pressure on the whale sharks in Oslob. The long-term effects of the observed behavioural modifications along with the high tourism pressure remain unknown. However, management plans are traditionally based on the precautionary principle, which aims to take preventive actions even if data on cause and effect are still inconclusive. Hence, an improved enforcement of the code of conduct coupled with a reduction in the conditioning of the whale sharks through provisioning were proposed to minimise the impacts on whale sharks in Oslob.
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Affiliation(s)
- Anna Schleimer
- Odyssea Marine Research and Awareness , Diekirch , Luxembourg ; Large Marine Vertebrates Research Institute Philippines , Jagna, Bohol , Philippines
| | - Gonzalo Araujo
- Large Marine Vertebrates Research Institute Philippines , Jagna, Bohol , Philippines
| | - Luke Penketh
- Large Marine Vertebrates Research Institute Philippines , Jagna, Bohol , Philippines
| | - Anna Heath
- Large Marine Vertebrates Research Institute Philippines , Jagna, Bohol , Philippines
| | - Emer McCoy
- Large Marine Vertebrates Research Institute Philippines , Jagna, Bohol , Philippines
| | - Jessica Labaja
- Large Marine Vertebrates Research Institute Philippines , Jagna, Bohol , Philippines
| | - Anna Lucey
- Large Marine Vertebrates Research Institute Philippines , Jagna, Bohol , Philippines
| | - Alessandro Ponzo
- Large Marine Vertebrates Research Institute Philippines , Jagna, Bohol , Philippines ; Large Marine Vertebrates Project Philippines, Physalus , Largo Callifonte, Roma , Italy
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