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Dedman S, Moxley JH, Papastamatiou YP, Braccini M, Caselle JE, Chapman DD, Cinner JE, Dillon EM, Dulvy NK, Dunn RE, Espinoza M, Harborne AR, Harvey ES, Heupel MR, Huveneers C, Graham NAJ, Ketchum JT, Klinard NV, Kock AA, Lowe CG, MacNeil MA, Madin EMP, McCauley DJ, Meekan MG, Meier AC, Simpfendorfer CA, Tinker MT, Winton M, Wirsing AJ, Heithaus MR. Ecological roles and importance of sharks in the Anthropocene Ocean. Science 2024; 385:adl2362. [PMID: 39088608 DOI: 10.1126/science.adl2362] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Accepted: 05/17/2024] [Indexed: 08/03/2024]
Abstract
In ecosystems, sharks can be predators, competitors, facilitators, nutrient transporters, and food. However, overfishing and other threats have greatly reduced shark populations, altering their roles and effects on ecosystems. We review these changes and implications for ecosystem function and management. Macropredatory sharks are often disproportionately affected by humans but can influence prey and coastal ecosystems, including facilitating carbon sequestration. Like terrestrial predators, sharks may be crucial to ecosystem functioning under climate change. However, large ecosystem effects of sharks are not ubiquitous. Increasing human uses of oceans are changing shark roles, necessitating management consideration. Rebuilding key populations and incorporating shark ecological roles, including less obvious ones, into management efforts are critical for retaining sharks' functional value. Coupled social-ecological frameworks can facilitate these efforts.
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Affiliation(s)
- Simon Dedman
- Institute of Environment, Department of Biological Sciences, Florida International University, North Miami, FL 33181, USA
| | - Jerry H Moxley
- Institute of Environment, Department of Biological Sciences, Florida International University, North Miami, FL 33181, USA
| | - Yannis P Papastamatiou
- Institute of Environment, Department of Biological Sciences, Florida International University, North Miami, FL 33181, USA
| | - Matias Braccini
- Western Australian Fisheries and Marine Research Laboratories, Department of Primary Industries and Regional Development, North Beach, WA 6920, Australia
| | - Jennifer E Caselle
- Marine Science Institute, University of California, Santa Barbara, CA 93106, USA
| | - Demian D Chapman
- Sharks and Rays Conservation Research Program, Mote Marine Laboratory, Sarasota, FL 34236, USA
| | - Joshua Eli Cinner
- Thriving Oceans Research Hub, School of Geosciences, University of Sydney, Camperdown, NSW 2006, Australia
| | - Erin M Dillon
- Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, CA 93106, USA
- Smithsonian Tropical Research Institute, Balboa, Republic of Panama
| | - Nicholas K Dulvy
- Earth to Ocean Research Group, Department of Biological Sciences, Simon Fraser University, 8888 University Drive, Burnaby, BC V5A 1S6, Canada
| | - Ruth Elizabeth Dunn
- Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, UK
- The Lyell Centre, Heriot-Watt University, Edinburgh EH14 4BA, UK
| | - Mario Espinoza
- Centro de Investigación en Ciencias del Mar y Limnología, Universidad de Costa Rica, San Pedro de Montes de Oca, San José 2060-11501, Costa Rica
- Escuela de Biología, Universidad de Costa Rica, San Pedro de Montes de Oca, San José 2060-11501, Costa Rica
- MigraMar, Bodega Bay, CA 94923, USA
| | - Alastair R Harborne
- Institute of Environment, Department of Biological Sciences, Florida International University, North Miami, FL 33181, USA
| | - Euan S Harvey
- School of Molecular and Life Sciences, Curtin University, WA, Australia
| | - Michelle R Heupel
- Institute of Marine and Antarctic Studies, University of Tasmania, Hobart, TAS 7000, Australia
- Australian Institute of Marine Science, Townsville, QLD, Australia
- Integrated Marine Observing System, University of Tasmania, Hobart, TAS, Australia
| | - Charlie Huveneers
- College of Science and Engineering, Flinders University, Adelaide, SA, Australia
| | | | - James T Ketchum
- MigraMar, Bodega Bay, CA 94923, USA
- Pelagios Kakunjá, La Paz, Baja California Sur, Mexico
- Centro de Investigaciones Biológicas del Noroeste (CIBNOR), La Paz, Baja California Sur, Mexico
| | - Natalie V Klinard
- Department of Biology, Dalhousie University, Halifax, Nova Scotia, NS B3H 4R2, Canada
| | - Alison A Kock
- Cape Research Centre, South African National Parks, Cape Town, South Africa
- South African Institute for Aquatic Biodiversity (SAIAB), Makhanda (Grahamstown), South Africa
| | - Christopher G Lowe
- Department of Biological Sciences, California State University Long Beach, Long Beach, CA 90840, USA
| | - M Aaron MacNeil
- Department of Biology, Dalhousie University, Halifax, Nova Scotia, NS B3H 4R2, Canada
| | - Elizabeth M P Madin
- Hawai'i Institute of Marine Biology, University of Hawai'i at Mānoa, Kāne'ohe, HI 96744, USA
| | - Douglas J McCauley
- Marine Science Institute, University of California, Santa Barbara, CA 93106, USA
- Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, CA 93106, USA
| | - Mark G Meekan
- Australian Institute of Marine Science, Indian Ocean Marine Research Centre, Crawley, WA, Australia
| | - Amelia C Meier
- Hawai'i Institute of Marine Biology, University of Hawai'i at Mānoa, Kāne'ohe, HI 96744, USA
| | - Colin A Simpfendorfer
- Institute of Marine and Antarctic Studies, University of Tasmania, Hobart, TAS 7000, Australia
- College of Science and Engineering, James Cook University, 1 James Cook Drive, Townsville, QLD 4811, Australia
| | - M Tim Tinker
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, Santa Cruz, CA 95060, USA
- US Geological Survey, Western Ecological Research Center, Santa Cruz, CA, USA
| | - Megan Winton
- Atlantic White Shark Conservancy, North Chatham, MA 02650, USA
| | - Aaron J Wirsing
- School of Environmental and Forest Sciences, University of Washington, Seattle, WA 98195, USA
| | - Michael R Heithaus
- Institute of Environment, Department of Biological Sciences, Florida International University, North Miami, FL 33181, USA
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Young HS, McCauley FO, Micheli F, Dunbar RB, McCauley DJ. Shortened food chain length in a fished versus unfished coral reef. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2024; 34:e3002. [PMID: 38840322 DOI: 10.1002/eap.3002] [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: 06/15/2023] [Revised: 02/23/2024] [Accepted: 04/09/2024] [Indexed: 06/07/2024]
Abstract
Direct exploitation through fishing is driving dramatic declines of wildlife populations in ocean environments, particularly for predatory and large-bodied taxa. Despite wide recognition of this pattern and well-established consequences of such trophic downgrading on ecosystem function, there have been few empirical studies examining the effects of fishing on whole system trophic architecture. Understanding these kinds of structural impacts is especially important in coral reef ecosystems-often heavily fished and facing multiple stressors. Given the often high dietary flexibility and numerous functional redundancies in diverse ecosystems such as coral reefs, it is important to establish whether web architecture is strongly impacted by fishing pressure or whether it might be resilient, at least to moderate-intensity pressure. To examine this question, we used a combination of bulk and compound-specific stable isotope analyses measured across a range of predatory and low-trophic-level consumers between two coral reef ecosystems that differed with respect to fishing pressure but otherwise remained largely similar. We found that even in a high-diversity system with relatively modest fishing pressure, there were strong reductions in the trophic position (TP) of the three highest TP consumers examined in the fished system but no effects on the TP of lower-level consumers. We saw no evidence that this shortening of the affected food webs was being driven by changes in basal resource consumption, for example, through changes in the spatial location of foraging by consumers. Instead, this likely reflected internal changes in food web architecture, suggesting that even in diverse systems and with relatively modest pressure, human harvest causes significant compressions in food chain length. This observed shortening of these food webs may have many important emergent ecological consequences for the functioning of ecosystems impacted by fishing or hunting. Such important structural shifts may be widespread but unnoticed by traditional surveys. This insight may also be useful for applied ecosystem managers grappling with choices about the relative importance of protection for remote and pristine areas and the value of strict no-take areas to protect not just the raw constituents of systems affected by fishing and hunting but also the health and functionality of whole systems.
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Affiliation(s)
- Hillary S Young
- Department of Ecology, Evolution and Marine Biology, UC Santa Barbara, Santa Barbara, California, USA
| | | | - Fiorenza Micheli
- Oceans Department, Hopkins Marine Station, and Stanford Center for Ocean Solutions, Stanford University, Pacific Grove, California, USA
| | - Robert B Dunbar
- Oceans Department and Earth Systems Science, Stanford University, Pacific Grove, California, USA
| | - Douglas J McCauley
- Department of Ecology, Evolution and Marine Biology, UC Santa Barbara, Santa Barbara, California, USA
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Finnegan S, Harnik PG, Lockwood R, Lotze HK, McClenachan L, Kahanamoku SS. Using the Fossil Record to Understand Extinction Risk and Inform Marine Conservation in a Changing World. ANNUAL REVIEW OF MARINE SCIENCE 2024; 16:307-333. [PMID: 37683272 DOI: 10.1146/annurev-marine-021723-095235] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/10/2023]
Abstract
Understanding the long-term effects of ongoing global environmental change on marine ecosystems requires a cross-disciplinary approach. Deep-time and recent fossil records can contribute by identifying traits and environmental conditions associated with elevated extinction risk during analogous events in the geologic past and by providing baseline data that can be used to assess historical change and set management and restoration targets and benchmarks. Here, we review the ecological and environmental information available in the marine fossil record and discuss how these archives can be used to inform current extinction risk assessments as well as marine conservation strategies and decision-making at global to local scales. As we consider future research directions in deep-time and conservationpaleobiology, we emphasize the need for coproduced research that unites researchers, conservation practitioners, and policymakers with the communities for whom the impacts of climate and global change are most imminent.
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Affiliation(s)
- Seth Finnegan
- Department of Integrative Biology, University of California, Berkeley, California, USA; ,
| | - Paul G Harnik
- Department of Earth and Environmental Geosciences, Colgate University, Hamilton, New York, USA;
| | - Rowan Lockwood
- Department of Geology, William & Mary, Williamsburg, Virginia, USA;
| | - Heike K Lotze
- Department of Biology, Dalhousie University, Halifax, Nova Scotia, Canada;
| | - Loren McClenachan
- Department of History and School of Environmental Studies, University of Victoria, Victoria, British Columbia, Canada;
| | - Sara S Kahanamoku
- Department of Integrative Biology, University of California, Berkeley, California, USA; ,
- Hawai'i Sea Grant College Program, University of Hawai'i at Mānoa, Honolulu, Hawai'i, USA
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Dillon EM, Dunne EM, Womack TM, Kouvari M, Larina E, Claytor JR, Ivkić A, Juhn M, Carmona PSM, Robson SV, Saha A, Villafaña JA, Zill ME. Challenges and directions in analytical paleobiology. PALEOBIOLOGY 2023; 49:377-393. [PMID: 37809321 PMCID: PMC7615171 DOI: 10.1017/pab.2023.3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 10/10/2023]
Abstract
Over the last 50 years, access to new data and analytical tools has expanded the study of analytical paleobiology, contributing to innovative analyses of biodiversity dynamics over Earth's history. Despite-or even spurred by-this growing availability of resources, analytical paleobiology faces deep-rooted obstacles that stem from the need for more equitable access to data and best practices to guide analyses of the fossil record. Recent progress has been accelerated by a collective push toward more collaborative, interdisciplinary, and open science, especially by early-career researchers. Here, we survey four challenges facing analytical paleobiology from an early-career perspective: (1) accounting for biases when interpreting the fossil record; (2) integrating fossil and modern biodiversity data; (3) building data science skills; and (4) increasing data accessibility and equity. We discuss recent efforts to address each challenge, highlight persisting barriers, and identify tools that have advanced analytical work. Given the inherent linkages between these challenges, we encourage discourse across disciplines to find common solutions. We also affirm the need for systemic changes that reevaluate how we conduct and share paleobiological research.
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Affiliation(s)
- Erin M. Dillon
- Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, California 93106, U.S.A.; Smithsonian Tropical Research Institute, Balboa, Republic of Panama
| | - Emma M. Dunne
- GeoZentrum Nordbayern, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany; School of Geography, Earth and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom
| | - Tom M. Womack
- School of Geography, Environment and Earth Sciences, Victoria University of Wellington, P.O. Box 600, Wellington, New Zealand
| | - Miranta Kouvari
- Department of Earth Sciences, University College London, Gower Street, London WC1E 6BT, United Kingdom; Life Sciences Department, Natural History Museum, Cromwell Road, London SW7 5BD, United Kingdom
| | - Ekaterina Larina
- Jackson School of Geosciences, University of Texas, Austin, Texas 78712, U.S.A
| | - Jordan Ray Claytor
- Department of Biology, University of Washington, Seattle, Washington 98195, U.S.A; Burke Museum of Natural History and Culture, Seattle, Washington 98195, U.S.A
| | - Angelina Ivkić
- Department of Palaeontology, University of Vienna, Josef-Holaubek-Platz 2,1090 Vienna, Austria
| | - Mark Juhn
- Department of Ecology and Evolutionary Biology, University of California Los Angeles, Los Angeles, California 90095, U.S.A
| | - Pablo S. Milla Carmona
- Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Ciencias Geológicas, Buenos Aires C1428EGA, Argentina; Instituto de Estudios Andinos “Don Pablo Groeber” (IDEAN, UBA-CONICET), Buenos Aires C1428EGA, Argentina
| | - Selina Viktor Robson
- Department of Biological Sciences, University of Calgary, Calgary, Alberta T2N 1N4, Canada
| | - Anwesha Saha
- Institute of Palaeobiology, Polish Academy of Sciences, ul. Twarda 51/55, 00-818 Warsaw, Poland; Laboratory of Paleogenetics and Conservation Genetics, Centre of New Technologies (CeNT), University of Warsaw, S. Banacha 2c, 02-097 Warsaw, Poland
| | - Jaime A. Villafaña
- Department of Palaeontology, University of Vienna, Josef-Holaubek-Platz 2, 1090 Vienna, Austria; Centro de Investigación en Recursos Naturales y Sustentabilidad, Universidad Bernardo O ‘Higgins, Santiago 8370993, Chile
| | - Michelle E. Zill
- Department of Earth and Planetary Sciences, University of California Riverside, Riverside, California 92521, U.S.A
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Dillon EM, Pier JQ, Smith JA, Raja NB, Dimitrijević D, Austin EL, Cybulski JD, De Entrambasaguas J, Durham SR, Grether CM, Haldar HS, Kocáková K, Lin CH, Mazzini I, Mychajliw AM, Ollendorf AL, Pimiento C, Regalado Fernández OR, Smith IE, Dietl GP. What is conservation paleobiology? Tracking 20 years of research and development. Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.1031483] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Conservation paleobiology has coalesced over the last two decades since its formal coining, united by the goal of applying geohistorical records to inform the conservation, management, and restoration of biodiversity and ecosystem services. Yet, the field is still attempting to form an identity distinct from its academic roots. Here, we ask a deceptively simple question: What is conservation paleobiology? To track its development as a field, we synthesize complementary perspectives from a survey of the scientific community that is familiar with conservation paleobiology and a systematic literature review of publications that use the term. We present an overview of conservation paleobiology’s research scope and compare survey participants’ perceptions of what it is and what it should be as a field. We find that conservation paleobiologists use a variety of geohistorical data in their work, although research is typified by near-time records of marine molluscs and terrestrial mammals collected over local to regional spatial scales. Our results also confirm the field’s broad disciplinary basis: survey participants indicated that conservation paleobiology can incorporate information from a wide range of disciplines spanning conservation biology, ecology, historical ecology, paleontology, and archaeology. Finally, we show that conservation paleobiologists have yet to reach a consensus on how applied the field should be in practice. The survey revealed that many participants thought the field should be more applied but that most do not currently engage with conservation practice. Reflecting on how conservation paleobiology has developed over the last two decades, we discuss opportunities to promote community cohesion, strengthen collaborations within conservation science, and align training priorities with the field’s identity as it continues to crystallize.
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Courtship and Reproduction of the Whitetip Reef Shark Triaenodon obesus (Carcharhiniformes: Carcharhinidae) in an Ex Situ Environment, with a Description of the Late Embryonic Developmental Stage. Animals (Basel) 2022; 12:ani12233291. [PMID: 36496812 PMCID: PMC9737276 DOI: 10.3390/ani12233291] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2022] [Revised: 11/22/2022] [Accepted: 11/22/2022] [Indexed: 11/29/2022] Open
Abstract
Elasmobranchs represent a group of species under considerable anthropic pressure because of the scale of industrial and artisanal fisheries and the loss of essential areas for nursery and feeding, which are causing substantial population losses around the world. Reproduction in an ex situ environment enables a healthy population to be built and maintained in networks of public aquariums, increasing our knowledge of elasmobranch reproductive biology and offering the opportunity for reintroductions in areas where native populations have been removed. The study reports two successful pregnancies of the whitetip reef shark Triaenodon obesus, considered a vulnerable species by the International Union for the Conservation of Nature. Copulation and gestation data are provided, including ultrasound recordings of the late stage of embryo development. Ultrasonography was performed with the GE Logiq and convex transducer and revealed a fetus with defined fins and organogenesis, with definition of eyes, gills, liver, a heart with individualized chambers, partially defined kidneys, and a well-defined spiral intestine. A cartilaginous skeleton forming a posterior acoustic shadow was detailed, as well as a moving fetus with a biparietal diameter of 6.47 cm and a heart rate of 62 Beats Per Minute on spectral Doppler. This is the first successful reproduction of T. obesus in an aquarium in Brazil.
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Banker RMW, Dineen AA, Sorman MG, Tyler CL, Roopnarine PD. Beyond functional diversity: The importance of trophic position to understanding functional processes in community evolution. Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.983374] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Ecosystem structure—that is the species present, the functions they represent, and how those functions interact—is an important determinant of community stability. This in turn affects how ecosystems respond to natural and anthropogenic crises, and whether species or the ecological functions that they represent are able to persist. Here we use fossil data from museum collections, literature, and the Paleobiology Database to reconstruct trophic networks of Tethyan paleocommunities from the Anisian and Carnian (Triassic), Bathonian (Jurassic), and Aptian (Cretaceous) stages, and compare these to a previously reconstructed trophic network from a modern Jamaican reef community. We generated model food webs consistent with functional structure and taxon richnesses of communities, and compared distributions of guild level parameters among communities, to assess the effect of the Mesozoic Marine Revolution on ecosystem dynamics. We found that the trophic space of communities expanded from the Anisian to the Aptian, but this pattern was not monotonic. We also found that trophic position for a given guild was subject to variation depending on what other guilds were present in that stage. The Bathonian showed the lowest degree of trophic omnivory by top consumers among all Mesozoic networks, and was dominated by longer food chains. In contrast, the Aptian network displayed a greater degree of short food chains and trophic omnivory that we attribute to the presence of large predatory guilds, such as sharks and bony fish. Interestingly, the modern Jamaican community appeared to have a higher proportion of long chains, as was the case in the Bathonian. Overall, results indicate that trophic structure is highly dependent on the taxa and ecological functions present, primary production experienced by the community, and activity of top consumers. Results from this study point to a need to better understand trophic position when planning restoration activities because a community may be so altered by human activity that restoring a species or its interactions may no longer be possible, and alternatives must be considered to restore an important function. Further work may also focus on elucidating the precise roles of top consumers in moderating network structure and community stability.
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Poscai AN, da Silva JPCB, Casas ALS, Lenktaitis P, Gadig OBF. Morphological study of the oral denticles of the porbeagle shark Lamna nasus. JOURNAL OF FISH BIOLOGY 2022; 101:226-235. [PMID: 35578984 DOI: 10.1111/jfb.15102] [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: 02/24/2022] [Accepted: 05/10/2022] [Indexed: 06/15/2023]
Abstract
Oral denticles of sharks are composed by a crown, dentine covered by a layer of enameloid and pulp cavity, the same structure of the dermal denticles found across the body surface of most elasmobranchs. In addition, oral papillae and taste buds are distributed among denticles within the oropharyngeal cavity, playing a fundamental role for tasting as part of the chemosensory system of fishes. Scanning electron microscopy (SEM) has been employed as an important tool for the study of dermal denticles and other structures, as well as histology and more recently computed tomography (CT) scan analysis. Herein, the authors used two methods for the study of the morphology of the oropharyngeal cavity of Lamna nasus (Lamniformes), an oceanic and pelagic shark: SEM and CT scan. The general morphology of oral denticles studied herein is related to abrasion strength as they are diamond-shaped, lack lateral cusps and have less pronounced ridges. In addition, smooth ridges and broad rounded denticles could be related to prevent abrasion during food consumption and manipulation. Oral papillae had a round shape and were observed only under SEM. The densities of papillae were estimated in 100 per cm2 , whereas denticles were 1760 and 1230 cm2 over the dorsal and ventral regions, respectively. The high numbers of denticles are inversely proportional to papillae density; denticles seem to restrict papillae distribution. Regarding the differences between methodologies, under SEM, only the crown was visualized, as well the papillae, allowing the estimation of size and density of both structures. Nonetheless, under CT scan, the whole components of denticles were clearly visualized: different views of the crown, peduncle, basal plate, and pulp cavity. On the contrary, oral papillae were not visualized under CT due to the tissue preparation. Furthermore, both methods are complementary and were important to extract as much information as possible from denticles and papillae.
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Affiliation(s)
- Aline N Poscai
- Instituto de Biociências, Campus de Rio Claro, Universidade Estadual Paulista "Júlio de Mesquita Filho", Rio Claro, Brazil
- Laboratório de Pesquisa de Elasmobrânquios, Instituto de Biociências, Universidade Estadual Paulista "Júlio de Mesquita Filho", São Vicente, Brazil
| | - João Paulo C B da Silva
- Departamento de Sistemática e Ecologia, Centro de Ciências Exatas e da Natureza, Universidade Federal da Paraíba, João Pessoa, Brazil
| | - André Luis S Casas
- Departamento de Ciências do Mar, Instituto do Mar, Universidade Federal de São Paulo, Santos, Brazil
| | - Phillip Lenktaitis
- Laboratório de Histologia, Departamento de Zoologia, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brazil
| | - Otto B F Gadig
- Instituto de Biociências, Campus de Rio Claro, Universidade Estadual Paulista "Júlio de Mesquita Filho", Rio Claro, Brazil
- Laboratório de Pesquisa de Elasmobrânquios, Instituto de Biociências, Universidade Estadual Paulista "Júlio de Mesquita Filho", São Vicente, Brazil
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Sibert EC, Rubin LD. Response to Comment on "An early Miocene extinction in pelagic sharks". Science 2021; 374:eabj9522. [PMID: 34882450 DOI: 10.1126/science.abj9522] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
[Figure: see text].
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Affiliation(s)
- Elizabeth C Sibert
- Department of Earth and Planetary Sciences, Yale University, New Haven, CT 06511, USA.,Yale Institute for Biospheric Sciences, Yale University, New Haven, CT 06511, USA
| | - Leah D Rubin
- Department of Environmental and Forest Biology, SUNY College of Environmental Science and Forestry, Syracuse, NY 13210, USA.,College of the Atlantic, Bar Harbor, ME 04609, USA
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10
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Fossil dermal denticles reveal the preexploitation baseline of a Caribbean coral reef shark community. Proc Natl Acad Sci U S A 2021; 118:2017735118. [PMID: 34230097 DOI: 10.1073/pnas.2017735118] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Preexploitation shark baselines and the history of human impact on coral reef-associated shark communities in the Caribbean are tpoorly understood. We recovered shark dermal denticles from mid-Holocene (∼7 ky ago) and modern reef sediments in Bocas del Toro, Caribbean Panama, to reconstruct an empirical shark baseline before major human impact and to quantify how much the modern shark community in the region had shifted from this historical reference point. We found that denticle accumulation rates, a proxy for shark abundance, declined by 71% since the mid-Holocene. All denticle morphotypes, which reflect shark community composition, experienced significant losses, but those morphotypes found on fast-swimming, pelagic sharks (e.g., families Carcharhinidae and Sphyrnidae) declined the most. An analysis of historical records suggested that the steepest decline in shark abundance occurred in the late 20th century, coinciding with the advent of a targeted shark fishery in Panama. Although the disproportionate loss of denticles characterizing pelagic sharks was consistent with overfishing, the large reduction in denticles characterizing demersal species with low commercial value (i.e., the nurse shark Ginglymostoma cirratum) indicated that other stressors could have exacerbated these declines. We demonstrate that the denticle record can reveal changes in shark communities over long ecological timescales, helping to contextualize contemporary abundances and inform shark management and ecology.
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Jorgensen SJ, Micheli F, White TD, Van Houtan KS, Alfaro-Shigueto J, Andrzejaczek S, Arnoldi NS, Baum JK, Block B, Britten GL, Butner C, Caballero S, Cardeñosa D, Chapple TK, Clarke S, Cortés E, Dulvy NK, Fowler S, Gallagher AJ, Gilman E, Godley BJ, Graham RT, Hammerschlag N, Harry AV, Heithaus M, Hutchinson M, Huveneers C, Lowe CG, Lucifora LO, MacKeracher T, Mangel JC, Barbosa Martins AP, McCauley DJ, McClenachan L, Mull C, Natanson LJ, Pauly D, Pazmiño DA, Pistevos JCA, Queiroz N, Roff G, Shea BD, Simpfendorfer CA, Sims DW, Ward-Paige C, Worm B, Ferretti F. Emergent research and priorities for shark and ray conservation. ENDANGER SPECIES RES 2021. [DOI: 10.3354/esr01169] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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