Braun Camrin D.

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Camrin D.

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  • Article
    Mesoscale eddies influence the movements of mature female white sharks in the Gulf Stream and Sargasso Sea
    (Nature Publishing Group, 2018-05-09) Gaube, Peter ; Braun, Camrin D. ; Lawson, Gareth L. ; McGillicuddy, Dennis J. ; Penna, Alice Della ; Skomal, Gregory B. ; Fischer, Chris ; Thorrold, Simon R.
    Satellite-tracking of mature white sharks (Carcharodon carcharias) has revealed open-ocean movements spanning months and covering tens of thousands of kilometers. But how are the energetic demands of these active apex predators met as they leave coastal areas with relatively high prey abundance to swim across the open ocean through waters often characterized as biological deserts? Here we investigate mesoscale oceanographic variability encountered by two white sharks as they moved through the Gulf Stream region and Sargasso Sea in the North Atlantic Ocean. In the vicinity of the Gulf Stream, the two mature female white sharks exhibited extensive use of the interiors of clockwise-rotating anticyclonic eddies, characterized by positive (warm) temperature anomalies. One tagged white shark was also equipped with an archival tag that indicated this individual made frequent dives to nearly 1,000 m in anticyclones, where it was presumably foraging on mesopelagic prey. We propose that warm temperature anomalies in anticyclones make prey more accessible and energetically profitable to adult white sharks in the Gulf Stream region by reducing the physiological costs of thermoregulation in cold water. The results presented here provide valuable new insight into open ocean habitat use by mature, female white sharks that may be applicable to other large pelagic predators.
  • Article
    Mesoscale eddies release pelagic sharks from thermal constraints to foraging in the ocean twilight zone
    (National Academy of Sciences, 2019-08-06) Braun, Camrin D. ; Gaube, Peter ; Sinclair-Taylor, Tane H. ; Skomal, Gregory B. ; Thorrold, Simon R.
    Mesoscale eddies are critical components of the ocean’s “internal weather” system. Mixing and stirring by eddies exerts significant control on biogeochemical fluxes in the open ocean, and eddies may trap distinctive plankton communities that remain coherent for months and can be transported hundreds to thousands of kilometers. Debate regarding how and why predators use fronts and eddies, for example as a migratory cue, enhanced forage opportunities, or preferred thermal habitat, has been ongoing since the 1950s. The influence of eddies on the behavior of large pelagic fishes, however, remains largely unexplored. Here, we reconstruct movements of a pelagic predator, the blue shark (Prionace glauca), in the Gulf Stream region using electronic tags, earth-observing satellites, and data-assimilating ocean forecasting models. Based on >2,000 tracking days and nearly 500,000 high-resolution time series measurements collected by 15 instrumented individuals, we show that blue sharks seek out the interiors of anticyclonic eddies where they dive deep while foraging. Our observations counter the existing paradigm that anticyclonic eddies are unproductive ocean “deserts” and suggest anomalously warm temperatures in these features connect surface-oriented predators to the most abundant fish community on the planet in the mesopelagic. These results also shed light on the ecosystem services provided by mesopelagic prey. Careful consideration will be needed before biomass extraction from the ocean twilight zone to avoid interrupting a key link between planktonic production and top predators. Moreover, robust associations between targeted fish species and oceanographic features increase the prospects for effective dynamic ocean management.
  • Article
    Diving behavior of the reef manta ray links coral reefs with adjacent deep pelagic habitats
    (Public Library of Science, 2014-02-06) Braun, Camrin D. ; Skomal, Gregory B. ; Thorrold, Simon R. ; Berumen, Michael L.
    Recent successful efforts to increase protection for manta rays has highlighted the lack of basic ecological information, including vertical and horizontal movement patterns, available for these species. We deployed pop-up satellite archival transmitting tags on nine reef manta rays, Manta alfredi, to determine diving behaviors and vertical habitat use. Transmitted and archived data were obtained from seven tagged mantas over deployment periods of 102–188 days, including three recovered tags containing 2.6 million depth, temperature, and light level data points collected every 10 or 15 seconds. Mantas frequented the upper 10 m during daylight hours and tended to occupy deeper water throughout the night. Six of the seven individuals performed a cumulative 76 deep dives (>150 m) with one individual reaching 432 m, extending the known depth range of this coastal, reef-oriented species and confirming its role as an ecological link between epipelagic and mesopelagic habitats. Mean vertical velocities calculated from high-resolution dive data (62 dives >150 m) from three individuals suggested that mantas may use gliding behavior during travel and that this behavior may prove more efficient than continuous horizontal swimming. The behaviors in this study indicate manta rays provide a previously unknown link between the epi- and mesopelagic layers of an extremely oligotrophic marine environment and provide evidence of a third marine species that utilizes gliding to maximize movement efficiency.
  • Preprint
    HMMoce : an R package for improved geolocation of archival-tagged fishes using a hidden Markov method
    ( 2017-11) Braun, Camrin D. ; Galuardi, Benjamin ; Thorrold, Simon R.
    Electronic tagging of marine fishes is commonly achieved with archival tags that rely on light levels and sea surface temperatures to retrospectively estimate movements. However, methodological issues associated with light-level geolocation have constrained meaningful inference to species where it is possible to accurately estimate time of sunrise and sunset. Most studies have largely ignored the oceanographic profiles collected by the tag as a potential way to refine light-level geolocation estimates. Open-source oceanographic measurements and outputs from high-resolution models are increasingly available and accessible. Temperature and depth profiles recorded by electronic tags can be integrated with these empirical data and model outputs to construct likelihoods and improve geolocation estimates. The R package HMMoce leverages available tag and oceanographic data to improve position estimates derived from electronic tags using a hidden Markov approach. We illustrate the use of the model and test its performance using example blue and mako shark archival tag data. Model results were validated using independent, known tracks and compared to results from other geolocation approaches. HMMoce exhibited as much as 6-fold improvement in pointwise error as compared to traditional light-level geolocation approaches. The results demonstrated the general applicability of HMMoce to marine animals, particularly those that do not frequent surface waters during crepuscular periods.
  • Preprint
    Remote marine protected area reveals unusual social behaviour in Chaetodon trifascialis
    ( 2016-06) Coker, Darren J. ; Braun, Camrin D. ; Cavin, Julie M. ; Payet, S. ; Berumen, Michael L.
  • Article
    A standardisation framework for bio-logging data to advance ecological research and conservation
    (Wiley, 2021-03-15) Sequeira, Ana M. M. ; O'Toole, Malcolm ; Keates, Theresa R. ; McDonnell, Laura H. ; Braun, Camrin D. ; Hoenner, Xavier ; Jaine, Fabrice R. A. ; Jonsen, Ian ; Newman, Peggy ; Pye, Jonathan ; Bograd, Steven ; Hays, Graeme ; Hazen, Elliott L. ; Holland, Melinda ; Tsontos, Vardis ; Blight, Clint ; Cagnacci, Francesca ; Davidson, Sarah C. ; Dettki, Holger ; Duarte, Carlos M. ; Dunn, Daniel C. ; Eguíluz, Víctor M. ; Fedak, Michael ; Gleiss, Adrian C. ; Hammerschlag, Neil ; Hindell, Mark ; Holland, Kim ; Janekovic, Ivica ; McKinzie, Megan K. ; Muelbert, Monica M. C. ; Pattiaratchi, Charitha ; Rutz, Christian ; Sims, David W. ; Simmons, Samantha E. ; Townsend, Brendal ; Whoriskey, Frederick G. ; Woodward, Bill ; Costa, Daniel P. ; Heupel, Michelle R. ; McMahon, Clive R. ; Harcourt, Robert ; Weise, Michael
    1. Bio-logging data obtained by tagging animals are key to addressing global conservation challenges. However, the many thousands of existing bio-logging datasets are not easily discoverable, universally comparable, nor readily accessible through existing repositories and across platforms, slowing down ecological research and effective management. A set of universal standards is needed to ensure discoverability, interoperability and effective translation of bio-logging data into research and management recommendations. 2. We propose a standardisation framework adhering to existing data principles (FAIR: Findable, Accessible, Interoperable and Reusable; and TRUST: Transparency, Responsibility, User focus, Sustainability and Technology) and involving the use of simple templates to create a data flow from manufacturers and researchers to compliant repositories, where automated procedures should be in place to prepare data availability into four standardised levels: (a) decoded raw data, (b) curated data, (c) interpolated data and (d) gridded data. Our framework allows for integration of simple tabular arrays (e.g. csv files) and creation of sharable and interoperable network Common Data Form (netCDF) files containing all the needed information for accuracy-of-use, rightful attribution (ensuring data providers keep ownership through the entire process) and data preservation security. 3. We show the standardisation benefits for all stakeholders involved, and illustrate the application of our framework by focusing on marine animals and by providing examples of the workflow across all data levels, including filled templates and code to process data between levels, as well as templates to prepare netCDF files ready for sharing. 4. Adoption of our framework will facilitate collection of Essential Ocean Variables (EOVs) in support of the Global Ocean Observing System (GOOS) and inter-governmental assessments (e.g. the World Ocean Assessment), and will provide a starting point for broader efforts to establish interoperable bio-logging data formats across all fields in animal ecology.
  • Article
    Diving into the vertical dimension of elasmobranch movement ecology
    (American Association for the Advancement of Science, 2022-08-19) Armstrong, Amelia J. ; Carlisle, Aaron ; Coffey, Daniel M. ; Gleiss, Adrian C. ; Huveneers, Charlie ; Jacoby, David M. P. ; Meekan, Mark G. ; Mourier, Johann ; Peel, Lauren R. ; Afonso, André S. ; Anderson, Scot D. ; Bach, Pascal ; Bennett, Mike B. ; Bezerra, Natalia A. ; Boustany, Andre M. ; Bowlby, Heather D. ; Branco, Ilka ; Braun, Camrin D. ; Brooks, Edward J. ; Burke, Patrick J. ; Butcher, Paul ; Chapple, Taylor K. ; Chateau, Olivier ; Coelho, Rui ; Cowley, Paul D. ; Croll, Donald A. ; Cuevas, Juan M. ; Curtis, Tobey H. ; Dagorn, Laurent ; Dale, Jonathan J. ; Daly, Ryan ; Dewar, Heidi ; Doherty, Philip D. ; Dove, Alistair D. M. ; Dudgeon, Christine L. ; Ellis, Jim R. ; Farrugia, Thomas J. ; Ferreira, Luciana C. ; Filmalter, John D. ; Finucci, Brittany ; Galvan-Magana, Felipe ; García, Mirta L. ; Gaston, Troy F. ; Gillanders, Bronwyn M. ; Green, Jonathan R. ; Hasan, Abdi ; Hawkes, Lucy A. ; Hedges, Kevin J. ; Henderson, Suzanne M. ; Holdsworth, John ; Howey, Lucy A. ; Humphries, Nicholas E. ; Jaine, Fabrice R. A. ; Kanive, Paul E. ; Labaja, Jessica ; Lana, Fernanda O. ; Lassauce, Hugo ; Llewellyn, Fiona ; Mambrasar, Ronald ; McCully Phillips, Sophy R. ; McGregor, Frazer ; McMillan, Matthew N. ; McNaughton, Lianne M. ; Mendonça, Sibele A. ; Meyer, Carl G. ; Mohan, John A. ; Musyl, Michael K. ; Natanson, Lisa J. ; Oliveira, Paulo ; Papastamtiou, Yannis P. ; Patterson, Toby A. ; Pierce, Simon J. ; Queiroz, Nuno ; Radford, Craig A. ; Saunders, Ryan A. ; Semmens, Jayson M. ; Setyawan, Edy ; Shidqi, Rafid A. ; Shipley, Oliver N. ; Shivji, Mahmood S. ; Sianipar, Abraham B. ; Silva, Joana F. ; Sims, David W. ; Sousa, Lara L. ; Spaet, Julia L. Y. ; Syakurachman, Ismail ; Thorrold, Simon R. ; Tolloti, Mariana T. ; Travassos, Paulo ; Tyminski, John P. ; Veras, Drausio ; Wantiez, Laurent ; Weber, Sam B. ; Weng, Kevin C. ; Williamson, Jane E. ; Witt, Matthew J. ; Wright, Serena ; Zilliacus, Kelly ; Block, Barbara A. ; Curnick, David J.
    Knowledge of the three-dimensional movement patterns of elasmobranchs is vital to understand their ecological roles and exposure to anthropogenic pressures. To date, comparative studies among species at global scales have mostly focused on horizontal movements. Our study addresses the knowledge gap of vertical movements by compiling the first global synthesis of vertical habitat use by elasmobranchs from data obtained by deployment of 989 biotelemetry tags on 38 elasmobranch species. Elasmobranchs displayed high intra- and interspecific variability in vertical movement patterns. Substantial vertical overlap was observed for many epipelagic elasmobranchs, indicating an increased likelihood to display spatial overlap, biologically interact, and share similar risk to anthropogenic threats that vary on a vertical gradient. We highlight the critical next steps toward incorporating vertical movement into global management and monitoring strategies for elasmobranchs, emphasizing the need to address geographic and taxonomic biases in deployments and to concurrently consider both horizontal and vertical movements.Vertical habitat use by sharks, rays, and skates varies globally and has implications for their conservation and management.
  • Article
    First records of two large pelagic fishes in the Red Sea: wahoo (Acanthocybium solandri) and striped marlin (Kajikia audax)
    (Cambridge University Press, 2022-11-02) Williams, Collin T. ; Arostegui, Martin C. ; Braun, Camrin D. ; Gaube, Peter ; Shriem, Marwan ; Berumen, Michael L.
    This report provides the first confirmed identifications of wahoo (Acanthocybium solandri) and striped marlin (Kajikia audax) in the Red Sea, expanding the known ranges of these species into the basin. Potential mechanisms responsible for the lack of regional documentation of the two species are further discussed. These findings illustrate the need for systematic biodiversity surveys of pelagic fish assemblages in the Red Sea.
  • Article
    Horizontal and vertical movement patterns and habitat use of juvenile porbeagles (Lamna nasus) in the Western North Atlantic
    (Frontiers Media, 2021-02-01) Skomal, Gregory B. ; Marshall, Heather ; Galuardi, Benjamin ; Natanson, Lisa J. ; Braun, Camrin D. ; Bernal, Diego
    The porbeagle (Lamna nasus) is a large, highly migratory endothermic shark broadly distributed in the higher latitudes of the Atlantic, South Pacific, and Indian Oceans. In the North Atlantic, the porbeagle has a long history of fisheries exploitation and current assessments indicate that this stock is severely overfished. Although much is known of the life history of this species, there is little fisheries-independent information about habitat preferences and ecology. To examine migratory routes, vertical behavior, and environmental associations in the western North Atlantic, we deployed pop-up satellite archival transmitting tags on 20 porbeagles in late November, 2006. The sharks, ten males and ten females ranging from 128 to 154 cm fork length, were tagged and released from a commercial longline fishing vessel on the northwestern edge of Georges Bank, about 150 km east of Cape Cod, MA. The tags were programmed to release in March (n = 7), July (n = 7), and November (n = 6) of 2007, and 17 (85%) successfully reported. Based on known and derived geopositions, the porbeagles exhibited broad seasonally-dependent horizontal and vertical movements ranging from minimum linear distances of 937 to 3,310 km and from the surface to 1,300 m, respectively. All of the sharks remained in the western North Atlantic from the Gulf of Maine, the Scotian Shelf, on George's Bank, and in the deep, oceanic waters off the continental shelf along the edge of, and within, the Gulf Stream. In general, the population appears to be shelf-oriented during the summer and early fall with more expansive offshore radiation in the winter and spring. Although sharks moved through temperatures ranging from 2 to 26°C, the bulk of their time (97%) was spent in 6-20°C. In the summer months, most of the sharks were associated with the continental shelf moving between the surface and the bottom and remaining < 200 m deep. In the late fall and winter months, the porbeagles moved into pelagic habitat and exhibited two behavioral patterns linked with the thermal features of the Gulf Stream: “non-divers” (n = 7) largely remained at epipelagic depths and “divers” (n = 10) made frequent dives into and remained at mesopelagic depths (200–1000 m). These data demonstrate that juvenile porbeagles are physiologically capable of exploiting the cool temperate waters of the western North Atlantic as well as the mesopelagic depths of the Gulf Stream, possibly allowing exploitation of prey not available to other predators.
  • Article
    Movements of the white shark Carcharodon carcharias in the North Atlantic Ocean
    (Inter-Research, 2017-09-29) Skomal, Gregory B. ; Braun, Camrin D. ; Chisholm, John H. ; Thorrold, Simon R.
    In the western North Atlantic, much of what is known about the movement ecology of the white shark Carcharodon carcharias is based on historical fisheries-dependent catch records, which portray a shelf-oriented species that moves north and south seasonally. In this study, we tagged 32 white sharks (16 females, 7 males, 9 unknown), ranging from 2.4 to 5.2 m total length, with satellite-based tags to investigate broad-scale movements in the North Atlantic. Based on 10427 days of tracking data, we found that white sharks are more broadly distributed, both horizontally and vertically, throughout the North Atlantic than previously understood, exhibiting an ontogenetic shift from near-coastal, shelf-oriented habitat to pelagic habitat with frequent excursions to mesopelagic depths. During the coastal phase, white sharks migrated seasonally from the northeast shelf in the summer to overwintering habitat off the southeastern US and the Gulf of Mexico, spending 95% of their time at <50 m depth. During the pelagic phase, subadult and adult white sharks exhibited wide-ranging movements during the fall, winter, and spring into the broader Atlantic over a 30° latitudinal range and as far east as the Azores. These sharks moved daily to depths of up to 1128 m, spending significant time at specific mesopelagic depth zones through a temperature range of 1.6 to 30.4°C. We believe these movements are associated with offshore foraging facilitated by the thermal physiology of the species. Our findings extend the known essential habitat for the white shark in the North Atlantic beyond existing protection, with implications for future conservation.
  • Article
    Pieces in a global puzzle: population genetics at two whale shark aggregations in the western Indian Ocean
    (Wiley Open Access, 2022-01-25) Hardenstine, Royale S. ; He, Song ; Cochran, Jesse E. M. ; Braun, Camrin D. ; Cagua, E. Fernando ; Pierce, Simon J. ; Prebble, Clare E. M. ; Rohner, Christoph A. ; Saenz-Agudelo, Pablo ; Sinclair-Taylor, Tane H. ; Skomal, Gregory B. ; Thorrold, Simon R. ; Watts, Alexandra M. ; Zakroff, Casey ; Berumen, Michael L.
    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.
  • Article
    Integrating archival tag data and a high-resolution oceanographic model to estimate basking shark (Cetorhinus maximus) movements in the western Atlantic
    (Frontiers Media, 2018-02) Braun, Camrin D. ; Skomal, Gregory B. ; Thorrold, Simon R.
    Basking shark (Cetorhinus maximus) populations are considered “vulnerable” globally and “endangered” in the northeast Atlantic by the International Union for the Conservation of Nature (IUCN). Much of our knowledge of this species comes from surface observations in coastal waters, yet recent evidence suggests the majority of their lives may be spent in the deep ocean. Depth preferences of basking sharks have significantly limited movement studies that used pop-up satellite archival transmitting (PSAT) tags as conventional light-based geolocation is impossible for tagged animals that spend significant time below the photic zone. We tagged 57 basking sharks with PSAT tags in the NW Atlantic from 2004 to 2011. Many individuals spent several months at meso- and bathy-pelagic depths where accurate light-level geolocation was impossible during fall, winter and spring. We applied a newly-developed geolocation approach for the PSAT data by comparing three-dimensional depth-temperature profile data recorded by the tags to modeled in situ oceanographic data from the high-resolution HYbrid Coordinate Ocean Model (HYCOM). Observation-based likelihoods were leveraged within a state-space hidden Markov model (HMM). The combined tracks revealed that basking sharks moved from waters around Cape Cod, MA to as far as the SE coast of Brazil (20°S), a total distance of over 17,000 km. Moreover, 59% of tagged individuals with sufficient deployment durations (>250 days) demonstrated seasonal fidelity to Cape Cod and the Gulf of Maine, with one individual returning to within 60 km of its tagging location 1 year later. Tagged sharks spent most of their time at epipelagic depths during summer months around Cape Cod and in the Gulf of Maine. During winter months, sharks spent extended periods at depths of at least 600 m while moving south to the Sargasso Sea, the Caribbean Sea, or the western tropical Atlantic. Our work demonstrates the utility of applying advances in oceanographic modeling to understanding habitat use of highly migratory, often meso- and bathy-pelagic, ocean megafauna. The large-scale movement patterns of tagged sharks highlight the need for international cooperation when designing and implementing conservation strategies to ensure that the species recovers from the historical effects of over-fishing throughout the North Atlantic Ocean.
  • Article
    Reef-fidelity and migration of tiger sharks, Galeocerdo cuvier, across the Coral Sea
    (Public Library of Science, 2014-01-08) Werry, Jonathan M. ; Planes, Serge ; Berumen, Michael L. ; Lee, Kate A. ; Braun, Camrin D. ; Clua, Eric
    Knowledge of the habitat use and migration patterns of large sharks is important for assessing the effectiveness of large predator Marine Protected Areas (MPAs), vulnerability to fisheries and environmental influences, and management of shark–human interactions. Here we compare movement, reef-fidelity, and ocean migration for tiger sharks, Galeocerdo cuvier, across the Coral Sea, with an emphasis on New Caledonia. Thirty-three tiger sharks (1.54 to 3.9 m total length) were tagged with passive acoustic transmitters and their localised movements monitored on receiver arrays in New Caledonia, the Chesterfield and Lord Howe Islands in the Coral Sea, and the east coast of Queensland, Australia. Satellite tags were also used to determine habitat use and movements among habitats across the Coral Sea. Sub-adults and one male adult tiger shark displayed year-round residency in the Chesterfields with two females tagged in the Chesterfields and detected on the Great Barrier Reef, Australia, after 591 and 842 days respectively. In coastal barrier reefs, tiger sharks were transient at acoustic arrays and each individual demonstrated a unique pattern of occurrence. From 2009 to 2013, fourteen sharks with satellite and acoustic tags undertook wide-ranging movements up to 1114 km across the Coral Sea with eight detected back on acoustic arrays up to 405 days after being tagged. Tiger sharks dove 1136 m and utilised three-dimensional activity spaces averaged at 2360 km3. The Chesterfield Islands appear to be important habitat for sub-adults and adult male tiger sharks. Management strategies need to consider the wide-ranging movements of large (sub-adult and adult) male and female tiger sharks at the individual level, whereas fidelity to specific coastal reefs may be consistent across groups of individuals. Coastal barrier reef MPAs, however, only afford brief protection for large tiger sharks, therefore determining the importance of other oceanic Coral Sea reefs should be a priority for future research.
  • Article
    Global collision-risk hotspots of marine traffic and the world’s largest fish, the whale shark
    (National Academy of Sciences, 2022-05-17) Womersley, Freya C. ; Humphries, Nicolas E. ; Queiroz, Nuno ; Vedor, Marisa ; da Costa, Ivo ; Furtado, Miguel ; Tyminski, John P. ; Abrantes, Katya ; Araujo, Gonzalo ; Bach, Steffen S. ; Barnett, Adam ; Berumen, Michael L. ; Bessudo Lion, Sandra ; Braun, Camrin D. ; Clingham, Elizabeth ; Cochran, Jesse E. M. ; de la Parra, Rafael ; Diamant, Stella ; Dove, Alistair D. M. ; Dudgeon, Christine L. ; Erdmann, Mark V. ; Espinoza, Eduardo ; Fitzpatrick, Richard ; Gonzalez Cano, Jaime ; Green, Jonathan R. ; Guzman, Hector M. ; Hardenstine, Royale ; Hasan, Abdi ; Hazin, Fabio H. V. ; Hearn, Alex R. ; Hueter, Robert ; Jaidah, Mohammed Y. ; Labaja, Jessica ; Ladino, Felipe ; Macena, Bruno C. L. ; Morris, John J. Jr. ; Norman, Bradley M. ; Penaherrera-Palma, Cesar ; Pierce, Simon J. ; Quintero, Lina M. ; Ramirez-Macias, Deni ; Reynolds, Samantha D. ; Richardson, Anthony J. ; Robinson, David P. ; Rohner, Christoph A. ; Rowat, David R. L. ; Sheaves, Marcus ; Shivji, Mahmood ; Sianipar, Abraham B. ; Skomal, Gregory B. ; Soler, German ; Syakurachman, Ismail ; Thorrold, Simon R. ; Webb, D. Harry ; Wetherbee, Bradley M. ; White, Timothy D. ; Clavelle, Tyler ; Kroodsma, David A. ; Thums, Michele ; Ferreira, Luciana C. ; Meekan, Mark G. ; Arrowsmith, Lucy M. ; Lester, Emily K. ; Meyers, Megan M. ; Peel, Lauren R. ; Sequeira, Ana M. M. ; Eguiluz, Victor M. ; Duarte, Carlos M. ; Sims, David W.
    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.
  • Preprint
    Convergence of marine megafauna movement patterns in coastal and open oceans
    ( 2017-09) Sequeira, Ana M. M. ; Rodríguez, Jorge P. ; Eguíluz, Víctor M. ; Harcourt, Robert ; Hindell, Mark ; Sims, David W. ; Duarte, Carlos M. ; Costa, Daniel P. ; Fernández-Gracia, Juan ; Ferreira, Luciana C. ; Hays, Graeme ; Heupel, Michelle R. ; Meekan, Mark G. ; Aven, Allen ; Bailleul, Frédéric ; Baylis, Alastair M. M. ; Berumen, Michael L. ; Braun, Camrin D. ; Burns, Jennifer ; Caley, M. Julian ; Campbell, R. ; Carmichael, Ruth H. ; Clua, Eric ; Einoder, Luke D. ; Friedlaender, Ari S. ; Goebel, Michael E. ; Goldsworthy, Simon D. ; Guinet, Christophe ; Gunn, John ; Hamer, D. ; Hammerschlag, Neil ; Hammill, Mike O. ; Hückstädt, Luis A. ; Humphries, Nicolas E. ; Lea, Mary-Anne ; Lowther, Andrew D. ; Mackay, Alice ; McHuron, Elizabeth ; McKenzie, J. ; McLeay, Lachlan ; McMahon, Cathy R. ; Mengersen, Kerrie ; Muelbert, Monica M. C. ; Pagano, Anthony M. ; Page, B. ; Queiroz, N. ; Robinson, Patrick W. ; Shaffer, Scott A. ; Shivji, Mahmood ; Skomal, Gregory B. ; Thorrold, Simon R. ; Villegas-Amtmann, Stella ; Weise, Michael ; Wells, Randall S. ; Wetherbee, Bradley M. ; Wiebkin, A. ; Wienecke, Barbara ; Thums, Michele
    The extent of increasing anthropogenic impacts on large marine vertebrates partly depends on the animals’ movement patterns. Effective conservation requires identification of the key drivers of movement including intrinsic properties and extrinsic constraints associated with the dynamic nature of the environments the animals inhabit. However, the relative importance of intrinsic versus extrinsic factors remains elusive. We analyse a global dataset of 2.8 million locations from > 2,600 tracked individuals across 50 marine vertebrates evolutionarily separated by millions of years and using different locomotion modes (fly, swim, walk/paddle). Strikingly, movement patterns show a remarkable convergence, being strongly conserved across species and independent of body length and mass, despite these traits ranging over 10 orders of magnitude among the species studied. This represents a fundamental difference between marine and terrestrial vertebrates not previously identified, likely linked to the reduced costs of locomotion in water. Movement patterns were primarily explained by the interaction between species-specific traits and the habitat(s) they move through, resulting in complex movement patterns when moving close to coasts compared to more predictable patterns when moving in open oceans. This distinct difference may be associated with greater complexity within coastal micro-habitats, highlighting a critical role of preferred habitat in shaping marine vertebrate global movements. Efforts to develop understanding of the characteristics of vertebrate movement should consider the habitat(s) through which they move to identify how movement patterns will alter with forecasted severe ocean changes, such as reduced Arctic sea ice cover, sea level rise and declining oxygen content.
  • Article
    Contrasting global, regional and local patterns of genetic structure in gray reef shark populations from the Indo-Pacific region
    (Nature Research, 2019-11-01) Boissin, Emilie ; Thorrold, Simon R. ; Braun, Camrin D. ; Zhou, Yuxiang ; Clua, Eric ; Planes, Serge
    Human activities have resulted in the loss of over 90% of sharks in most ocean basins and one in four species of elasmobranch are now listed at risk of extinction by the IUCN. How this collapse will affect the ability of populations to recover in the face of continued exploitation and global climate change remains unknown. Indeed, important ecological and biological information are lacking for most shark species, particularly estimates of genetic diversity and population structure over a range of spatial scales. Using 15 microsatellite markers, we investigated genetic diversity and population structure in gray reef sharks over their Indo-Pacific range (407 specimens from 9 localities). Clear genetic differentiation was observed between the Indian and the Pacific Ocean specimens (FST = 0.145***). Further differentiation within the Pacific included a West and East cleavage as well as North-Central and South-Central Pacific clusters. No genetic differentiation was detected within archipelagos. These results highlight the legacy of past climate changes and the effects of large ocean expanses and circulation patterns on contrasting levels of connectivity at global, regional and local scales. Our results indicate a need for regional conservation units for gray reef sharks and pinpoint the isolation and vulnerability of their French Polynesian population.
  • Preprint
    Movements of the reef manta ray (Manta alfredi) in the Red Sea using satellite and acoustic telemetry
    ( 2015-10-17) Braun, Camrin D. ; Skomal, Gregory B. ; Thorrold, Simon R. ; Berumen, Michael L.
    Populations of mobulid rays are declining globally through a combination of directed fisheries and indirect anthropogenic threats. Understanding the movement ecology of these rays remains an important priority for devising appropriate conservation measures throughout the world’s oceans. We sought to determine manta movements across several temporal and spatial scales with a focus on quantifying site fidelity and seasonality in the northern Farasan Banks, Red Sea. We fitted manta rays with acoustic transmitters (n = 9) and popup satellite archival transmitting (PSAT) tags (n = 9), including four with GPS capability (Fastloc), during spring 2011 and 2012. We deployed an extensive array of acoustic receivers (n = 67) to record movements of tagged mantas in the study area. All acoustically tagged individuals travelled frequently among highuse receiver locations and reefs and demonstrated fidelity to specific sites within the array. Estimated and realized satellite tag data indicated regional movements <200 km from the tagging location, largely coastal residency, and high surface occupation. GPStagged individuals regularly moved within the coastal reef matrix up to ~70 km to the south but continued to return to the tagging area near the highoccupancy sites identified in the acoustic array. We also tested the accuracy of several geolocation models to determine the best approach to analyze our lightbased satellite tag data. We documented significant errors in lightbased movement estimates that should be considered when interpreting tracks derived from lightlevel geolocation, especially for animals with restricted movements through a homogenous temperature field. Despite some error in satellite tag positions, combining results from PSAT and acoustic tags in this study yielded a comprehensive representation of manta spatial ecology across several scales, and such approaches will, in the future, inform the design of appropriate management strategies for manta rays in the Red Sea and tropical regions worldwide.
  • Article
    Home sweet home: spatiotemporal distribution and site fidelity of the reef manta ray (Mobula alfredi) in Dungonab Bay, Sudan
    (BMC, 2022-04-28) Knochel, Anna M. ; Hussey, Nigel E. ; Kessel, Steven T. ; Braun, Camrin D. ; Cochran, Jesse E. M. ; Hill, Graham ; Klaus, Rebecca ; Checkchak, Tarik ; Elamin El Hassen, Nasereldin M. ; Younnis, Mohammed ; Berumen, Michael L.
    Background Reef manta ray (Mobula alfredi) populations along the Northeastern African coastline are poorly studied. Identifying critical habitats for this species is essential for future research and conservation efforts. Dungonab Bay and Mukkawar Island National Park (DMNP), a component of a UNESCO World Heritage Site in Sudan, hosts the largest known M. alfredi aggregation in the Red Sea. Methods A total of 19 individuals were tagged using surgically implanted acoustic tags and tracked within DMNP on an array of 15 strategically placed acoustic receivers in addition to two offshore receivers. Two of these acoustically monitored M. alfredi were also equipped with satellite linked archival tags and one individual was fitted with a satellite transmitting tag. Together, these data are used to describe approximately two years of residency and seasonal shifts in habitat use. Results Tagged individuals were detected within the array on 96% of monitored days and recorded an average residence index of 0.39 across all receivers. Detections were recorded throughout the year, though some individuals were absent from the receiver array for weeks or months at a time, and generalized additive mixed models showed a clear seasonal pattern in presence with the highest probabilities of detection occurring in boreal fall. The models indicated that M. alfredi presence was highly correlated with increasing chlorophyll-a levels and weakly correlated with the full moon. Modeled biological factors, including sex and wingspan, had no influence on animal presence. Despite the high residency suggested by acoustic telemetry, satellite tag data and offshore acoustic detections in Sanganeb Atoll and Suedi Pass recorded individuals moving up to 125 km from the Bay. However, all these individuals were subsequently detected in the Bay, suggesting a strong degree of site fidelity at this location. Conclusions The current study adds to growing evidence that M. alfredi are highly resident and site-attached to coastal bays and lagoons but display seasonal shifts in habitat use that are likely driven by resource availability. This information can be used to assist in managing and supporting sustainable ecotourism within the DMNP, part of a recently designated UNESCO World Heritage Site.
  • Article
    Vertical movements of a pelagic thresher shark (Alopias pelagicus): insights into the species' physiological limitations and trophic ecology in the Red Sea
    (Inter Research, 2020-12-03) Arostegui, Martin C. ; Gaube, Peter ; Berumen, Michael L. ; DiGiulian, Anthony ; Jones, Burton H. ; Røstad, Anders ; Braun, Camrin D.
    The pelagic thresher shark Alopias pelagicus is an understudied elasmobranch harvested in commercial fisheries of the tropical Indo-Pacific. The species is endangered, overexploited throughout much of its range, and has a decreasing population trend. Relatively little is known about its movement ecology, precluding an informed recovery strategy. Here, we report the first results from an individual pelagic thresher shark outfitted with a pop-up satellite archival transmitting (PSAT) tag to assess its movement with respect to the species’ physiology and trophic ecology. A 19 d deployment in the Red Sea revealed that the shark conducted normal diel vertical migration, spending the majority of the day at 200-300 m in the mesopelagic zone and the majority of the night at 50-150 m in the epipelagic zone, with the extent of these movements seemingly not constrained by temperature. In contrast, the depth distribution of the shark relative to the vertical distribution of oxygen suggested that it was avoiding hypoxic conditions below 300 m even though that is where the daytime peak of acoustic backscattering occurs in the Red Sea. Telemetry data also indicated crepuscular and daytime overlap of the shark’s vertical habitat use with distinct scattering layers of small mesopelagic fishes and nighttime overlap with nearly all mesopelagic organisms in the Red Sea as these similarly undergo nightly ascents into epipelagic waters. We identify potential depths and diel periods in which pelagic thresher sharks may be most susceptible to fishery interactions, but more expansive research efforts are needed to inform effective management.
  • Article
    Extreme diving behaviour in devil rays links surface waters and the deep ocean
    (Nature Publishing Group, 2014-07-01) Thorrold, Simon R. ; Afonso, Pedro ; Fontes, Jorge ; Braun, Camrin D. ; Santos, Ricardo S. ; Skomal, Gregory B. ; Berumen, Michael L.
    Ecological connections between surface waters and the deep ocean remain poorly studied despite the high biomass of fishes and squids residing at depths beyond the euphotic zone. These animals likely support pelagic food webs containing a suite of predators that include commercially important fishes and marine mammals. Here we deploy pop-up satellite archival transmitting tags on 15 Chilean devil rays (Mobula tarapacana) in the central North Atlantic Ocean, which provide movement patterns of individuals for up to 9 months. Devil rays were considered surface dwellers but our data reveal individuals descending at speeds up to 6.0 m s−1 to depths of almost 2,000 m and water temperatures <4 °C. The shape of the dive profiles suggests that the rays are foraging at these depths in deep scattering layers. Our results provide evidence of an important link between predators in the surface ocean and forage species occupying pelagic habitats below the euphotic zone in ocean ecosystems.