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Gayford JH, Godfrey H, Whitehead DA. Ontogenetic morphometry of the brown smoothhound shark Mustelus henlei with implications for ecology and evolution. J Morphol 2023; 284:e21608. [PMID: 37458085 DOI: 10.1002/jmor.21608] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Revised: 05/17/2023] [Accepted: 05/29/2023] [Indexed: 07/18/2023]
Abstract
The central tenet of ecomorphology links ecological and morphological variation through the process of selection. Traditionally used to rationalise morphological differences between taxa, an ecomorphological approach is increasingly being utilised to study morphological differences expressed through ontogeny. Elasmobranchii (sharks, rays and skates) is one clade in which such ontogenetic shifts in body form have been reported. Such studies are limited to a relatively small proportion of total elasmobranch ecological and morphological diversity, and questions remain regarding the extent to which ecological selection are driving observed morphometric trends. In this study, we report ontogenetic growth trajectories obtained via traditional linear morphometrics from a large data set of the brown smoothhound shark (Mustelus henlei). We consider various morphological structures including the caudal, dorsal and pectoral fins, as well as several girth measurements. We use an ecomorphological approach to infer the broad ecological characteristics of this population and refine understanding of the selective forces underlying the evolution of specific morphological structures. We suggest that observed scaling trends in M. henlei are inconsistent with migratory behaviour, but do not contradict a putative trophic niche shift. We also highlight the role of predation pressure and sex-based ecological differences in driving observed trends in morphometry, a factor which has previously been neglected when considering the evolution of body form in sharks.
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Affiliation(s)
- Joel H Gayford
- Department of Life Sciences, Imperial College London, Ascot, UK
- Marine Research and Conservation Department, Investigación Tiburones México A.C, La Paz, Mexico
- Shark Measurements, London, UK
| | - Hana Godfrey
- Marine Research and Conservation Department, Investigación Tiburones México A.C, La Paz, Mexico
| | - Darren A Whitehead
- Marine Research and Conservation Department, Investigación Tiburones México A.C, La Paz, Mexico
- Instituto Politécnico Nacional, Centro Interdisciplinario de Ciencias Marinas, La Paz, México
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2
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Khalil AM, Gainsford A, van Herwerden L. DNA barcoding of fresh seafood in Australian markets reveals misleading labelling and sale of endangered species. JOURNAL OF FISH BIOLOGY 2023; 102:727-733. [PMID: 36624930 DOI: 10.1111/jfb.15308] [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: 09/26/2022] [Accepted: 01/04/2023] [Indexed: 06/17/2023]
Abstract
Flake and shark samples were purchased from outlets in several coastal Australian regions and genetically barcoded using the cytochrome oxidase subunit 1 (CO1) gene to investigate labelling reliability and species-specific sources of ambiguously labelled fillets. Of the 41 shark fillet samples obtained, 23 yielded high-quality CO1 sequences, out of which 57% (n = 13) were labelled ambiguously (misleading) and 35% (n = 8) incorrectly. In contrast, barramundi fillets, which are widely available and sought after in Australian markets, were shown to be accurately labelled. Species identified from shark samples, including the shortfin mako (n = 3) and the scalloped hammerhead (n = 1), are assessed by the IUCN as endangered and critically endangered, respectively, with several others classified as vulnerable and near threatened.
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Affiliation(s)
- Andrew M Khalil
- College of Science and Engineering, James Cook University, Townsville, Queensland, Australia
| | - Ashton Gainsford
- College of Science and Engineering, James Cook University, Townsville, Queensland, Australia
- Australian Research Council Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, Queensland, Australia
| | - Lynne van Herwerden
- College of Science and Engineering, James Cook University, Townsville, Queensland, Australia
- Centre for Sustainable Tropical Fisheries and Aquaculture, James Cook University, Townsville, Queensland, Australia
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3
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Population structure and genetic connectivity of the scalloped hammerhead shark (Sphyrna lewini) across nursery grounds from the Eastern Tropical Pacific: Implications for management and conservation. PLoS One 2022; 17:e0264879. [PMID: 36525407 PMCID: PMC9757582 DOI: 10.1371/journal.pone.0264879] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Accepted: 08/18/2022] [Indexed: 12/23/2022] Open
Abstract
Defining demographically independent units and understanding patterns of gene flow between them is essential for managing and conserving exploited populations. The critically endangered scalloped hammerhead shark, Sphyrna lewini, is a coastal semi-oceanic species found worldwide in tropical and subtropical waters. Pregnant females give birth in shallow coastal estuarine habitats that serve as nursery grounds for neonates and small juveniles, whereas adults move offshore and become highly migratory. We evaluated the population structure and connectivity of S. lewini in coastal areas and one oceanic island (Cocos Island) across the Eastern Tropical Pacific (ETP) using both sequences of the mitochondrial DNA control region (mtCR) and 9 nuclear-encoded microsatellite loci. The mtCR defined two genetically discrete groups: one in the Mexican Pacific and another one in the central-southern Eastern Tropical Pacific (Guatemala, Costa Rica, Panama, and Colombia). Overall, the mtCR data showed low levels of haplotype diversity ranging from 0.000 to 0.608, while nucleotide diversity ranged from 0.000 to 0.0015. More fine-grade population structure was detected using microsatellite loci where Guatemala, Costa Rica, and Panama differed significantly. Relatedness analysis revealed that individuals within nursery areas were more closely related than expected by chance, suggesting that S. lewini may exhibit reproductive philopatric behaviour within the ETP. Findings of at least two different management units, and evidence of philopatric behaviour call for intensive conservation actions for this highly threatened species in the ETP.
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4
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OUP accepted manuscript. Biol J Linn Soc Lond 2022. [DOI: 10.1093/biolinnean/blac035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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5
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Feeding ecology has shaped the evolution of modern sharks. Curr Biol 2021; 31:5138-5148.e4. [PMID: 34614390 DOI: 10.1016/j.cub.2021.09.028] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Revised: 06/05/2021] [Accepted: 09/09/2021] [Indexed: 11/20/2022]
Abstract
Sharks are iconic predators in today's oceans, yet their modern diversity has ancient origins. In particular, present hypotheses suggest that a combination of mass extinction, global climate change, and competition has regulated the community structure of dominant mackerel (Lamniformes) and ground (Carcharhiniformes) sharks over the last 66 million years. However, while these scenarios advocate an interplay of major abiotic and biotic events, the precise drivers remain obscure. Here, we focus on the role of feeding ecology using a geometric morphometric analysis of 3,837 fossil and extant shark teeth. Our results reveal that morphological segregation rather than competition has characterized lamniform and carcharhiniform evolution. Moreover, although lamniforms suffered a long-term disparity decline potentially linked to dietary "specialization," their recent disparity rivals that of "generalist" carcharhiniforms. We further confirm that low eustatic sea levels impacted lamniform disparity across the end-Cretaceous mass extinction. Adaptations to changing prey availability and the proliferation of coral reef habitats during the Paleogene also likely facilitated carcharhiniform dispersals and cladogenesis, underpinning their current taxonomic dominance. Ultimately, we posit that trophic partitioning and resource utilization shaped past shark ecology and represent critical determinants for their future species survivorship.
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6
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Evolutionary trends of the conserved neurocranium shape in angel sharks (Squatiniformes, Elasmobranchii). Sci Rep 2020; 10:12582. [PMID: 32724124 PMCID: PMC7387474 DOI: 10.1038/s41598-020-69525-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Accepted: 06/19/2020] [Indexed: 11/24/2022] Open
Abstract
Elasmobranchii (i.e., sharks, skates, and rays) forms one of the most diverse groups of marine predators. With a fossil record extending back into the Devonian, several modifications in their body plan illustrate their body shape diversity through time. The angel sharks, whose fossil record dates back to the Late Jurassic, some 160 Ma, have a dorsoventrally flattened body, similar to skates and rays. Fossil skeletons of this group show that the overall morphology was well established earlier in its history. By examining the skull shape of well-preserved fossil material compared to extant angel sharks using geometric morphometric methods, within a phylogenetic framework, we were able to determine the conservative skull shape among angel sharks with a high degree of integration. The morphospace occupation of extant angel sharks is rather restricted, with extensive overlap. Most of the differences in skull shape are related to their geographic distribution patterns. We found higher levels of disparity in extinct forms, but lower ones in extant species. Since angel sharks display a highly specialized prey capture behaviour, we suggest that the morphological integration and biogeographic processes are the main drivers of their diversity, which might limit their capacity to display higher disparities since their origin.
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Raoult V, Broadhurst MK, Peddemors VM, Williamson JE, Gaston TF. Resource use of great hammerhead sharks (Sphyrna mokarran) off eastern Australia. JOURNAL OF FISH BIOLOGY 2019; 95:1430-1440. [PMID: 31613987 DOI: 10.1111/jfb.14160] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Accepted: 09/27/2019] [Indexed: 06/10/2023]
Abstract
Great hammerhead sharks Sphyrna mokarran are the largest member of Sphyrnidae, yet the roles of these large sharks in the food webs of coastal ecosystems are still poorly understood. Here we obtained samples of muscle, liver and vertebrae from large S. mokarran (234-383 cm total length; LT ) caught as by-catch off eastern Australia and used stable-isotope analyses of δ15 N, δ13 C and δ34 S to infer their resource use and any associated ontogenetic patterns. The results indicated large S. mokarran are apex predators primarily relying on other sharks and rays for their diet, with a preference for benthic resources such as Australian cownose rays Rhinoperon neglecta during the austral summer. Teleosts, cephalopods and crustaceans were not significant components of S. mokarran diets, though some conspecifics appeared to rely on more diverse resources over the austral summer. Ontogenetic shifts in resource use were detected but trajectories of the increases in trophic level varied among individuals. Most S. mokarran had non-linear trajectories in ontogenetic resource-use shifts implying size was not the main explanatory factor. Stable isotope values of δ13 C and δ34 S in muscle suggest S. mokarran span coastal, pelagic and benthic food webs in eastern Australia.
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Affiliation(s)
- Vincent Raoult
- School of Environmlental and Life Sciences, University of Newcastle, Ourimbah, Australia
| | - Matt K Broadhurst
- New South Wales Department of Industries, Fisheries Conservation Technology Unit, National Marine Science Centre, Coffs Harbour, Australia
| | - Vic M Peddemors
- New South Wales of Department of Primary Industries, Fisheries, Sydney Institute of Marine Science, Mosman, Australia
| | - Jane E Williamson
- Department of Biological Sciences, Macquarie University, Sydney, Australia
| | - Troy F Gaston
- School of Environmlental and Life Sciences, University of Newcastle, Ourimbah, Australia
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Coiraton C, Tovar-Ávila J, Garcés-García KC, Rodríguez-Madrigal JA, Gallegos-Camacho R, Chávez-Arrenquín DA, Amezcua F. Periodicity of the growth-band formation in vertebrae of juvenile scalloped hammerhead shark Sphyrna lewini from the Mexican Pacific Ocean. JOURNAL OF FISH BIOLOGY 2019; 95:1072-1085. [PMID: 31318045 DOI: 10.1111/jfb.14100] [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: 02/22/2019] [Accepted: 07/17/2019] [Indexed: 06/10/2023]
Abstract
The age of 296 juvenile scalloped hammerhead sharks Sphyrna lewini caught by several fisheries in the Mexican Pacific Ocean from March 2007 to September 2017 were estimated from growth band counts in thin-sectioned vertebrae. Marginal-increment analysis (MIA) and centrum-edge analysis (CEA) were used to verify the periodicity of formation of the growth bands, whereas elemental profiles obtained from LA-ICP-MS transect scans in vertebrae of 15 juveniles were used as an alternative approach to verify the age of the species for the first time. Age estimates ranged from 0 to 10+ years (42-158.7 cm total length; LT ). The index of average percentage error (IAPE 3.6%), CV (5.2%), bias plots and Bowker's tests of symmetry showed precise and low-biased age estimation. Both MIA and CEA indicated that in the vertebrae of juveniles of S. lewini a single translucent growth band was formed during winter (November-March) and an opaque band during summer (July-September), a period of faster growth, apparently correlated with a higher sea surface temperature. Peaks in vertebral P and Mn content spatially corresponded with the annual banding pattern in most of the samples, displaying 1.19 and 0.88 peaks per opaque band, respectively, which closely matched the annual deposition rate observed in this study. Although the periodicity of growth band formation needs to be verified for all sizes and ages representing the population of the species in the region, this demonstration of the annual formation of the growth bands in the vertebrae of juveniles should lead to a re-estimation of the growth parameters and productivity of the population to ensure that it is harvested at sustainable levels.
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Affiliation(s)
- Claire Coiraton
- Posgrado en Ciencias del Mar y Limnología, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Javier Tovar-Ávila
- Centro Regional de Investigaciones Pesqueras Bahía Banderas, Nayarit, Mexico
| | | | | | | | - Dario A Chávez-Arrenquín
- Centro Regional de Investigaciones Pesqueras Mazatlán. Calzada Sábalo-Cerritos, Mazatlán, Mexico
| | - Felipe Amezcua
- Instituto de Ciencias del Mar y Limnología, Universidad Nacional Autónoma de México, Mazatlán, Mexico
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9
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Gonzalez C, Gallagher AJ, Caballero S. Conservation genetics of the bonnethead shark Sphyrna tiburo in Bocas del Toro, Panama: Preliminary evidence of a unique stock. PLoS One 2019; 14:e0220737. [PMID: 31415593 PMCID: PMC6695166 DOI: 10.1371/journal.pone.0220737] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Accepted: 07/21/2019] [Indexed: 12/04/2022] Open
Abstract
The bonnethead shark, Sphyrna tiburo, is a small elasmobranch distributed in the Eastern Pacific from southern California to Ecuador, and along the Western Atlantic, with preferences for continental margins of North, Central and South America, the Gulf of Mexico, and the Caribbean. Recent studies have suggested that it could be under a process of cryptic speciation, with the possibility to find different species in similar geographic locations. Here we assessed the population structure and genetic diversity of this highly philopatric and non-dispersive species in the Bocas del Toro Archipelago, Panama. Fragments of the mitochondrial genes cytochrome oxidase I and control region, were used to test the genetic structure of adult and juvenile S. tiburo in this area, and were compared with other locations of the Western Atlantic and Belize. We found significant genetic differentiation between Caribbean bonnethead sharks from Bocas del Toro and Belize, when compared to bonnetheads from other locations of the Western Atlantic. These results also suggest that Bocas del Toro could constitute a different genetic population unit for this species, whereby bonnethead sharks in this area could belong to a unique stock. The information obtained in this study could improve our understanding of the population dynamics of the bonnethead shark throughout its distribution range, and may be used as a baseline for future conservation initiatives for coastal sharks in Central America, a poorly studied an often overlooked region for shark conservation and research.
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Affiliation(s)
- Cindy Gonzalez
- Departamento de Ciencias Biológicas, Universidad de los Andes, Laboratorio de Ecología Molecular de Vertebrados Acuáticos—LEMVA, Bogota, Colombia
| | - Austin J. Gallagher
- Beneath the Waves Inc, Herndon, Virginia, United States of America
- Smithsonian Tropical Research Institute, Balboa, Panama City, Republic of Panama
- Rosentiel School of Marine and Atmospheric Sciences, University of Miami, Miami, Florida, United States of America
| | - Susana Caballero
- Departamento de Ciencias Biológicas, Universidad de los Andes, Laboratorio de Ecología Molecular de Vertebrados Acuáticos—LEMVA, Bogota, Colombia
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Taking Advantage of the Genomics Revolution for Monitoring and Conservation of Chondrichthyan Populations. DIVERSITY-BASEL 2019. [DOI: 10.3390/d11040049] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Chondrichthyes (sharks, rays, skates and chimaeras) are among the oldest extant predators and are vital to top-down regulation of oceanic ecosystems. They are an ecologically diverse group occupying a wide range of habitats and are thus, exploited by coastal, pelagic and deep-water fishing industries. Chondrichthyes are among the most data deficient vertebrate species groups making design and implementation of regulatory and conservation measures challenging. High-throughput sequencing technologies have significantly propelled ecological investigations and understanding of marine and terrestrial species’ populations, but there remains a paucity of NGS based research on chondrichthyan populations. We present a brief review of current methods to access genomic and metagenomic data from Chondrichthyes and discuss applications of these datasets to increase our understanding of chondrichthyan taxonomy, evolution, ecology and population structures. Last, we consider opportunities and challenges offered by genomic studies for conservation and management of chondrichthyan populations.
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11
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Rangel BDS, Salmon T, Poscai AN, Kfoury JR, Rici REG. Comparative investigation into the morphology of oral papillae and denticles of four species of lamnid and sphyrnid sharks. ZOOMORPHOLOGY 2018. [DOI: 10.1007/s00435-018-0427-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
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12
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DNA-based identification reveals illegal trade of threatened shark species in a global elasmobranch conservation hotspot. Sci Rep 2018; 8:3347. [PMID: 29463851 PMCID: PMC5820252 DOI: 10.1038/s41598-018-21683-5] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Accepted: 02/01/2018] [Indexed: 02/07/2023] Open
Abstract
Here, we report trading of endangered shark species in a world hotspot for elasmobranch conservation in Brazil. Data on shark fisheries are scarce in Brazil, although the northern and northeastern regions have the highest indices of shark bycatch. Harvest is made primarily with processed carcasses lacking head and fins, which hampers reliable species identification and law enforcement on illegal catches. We used partial sequences of two mitochondrial genes (COI and/or NADH2) to identify 17 shark species from 427 samples being harvested and marketed on the northern coast of Brazil. Nine species (53%) are listed under some extinction threat category according to Brazilian law and international authorities (IUCN – International Union for Conservation of Nature; CITES – Convention on International Trade of Endangered Species of Wild Fauna and Flora). The number increases to 13 (76%) if we also consider the Near Threatened category. Hammerhead sharks are under threat worldwide, and composed 18.7% of samples, with Sphyrna mokarran being the fourth most common species among samples. As illegal trade of threatened shark species is a worldwide conservation problem, molecular identification of processed meat or specimens lacking diagnostic body parts is a highly effective tool for species identification and law enforcement.
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14
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Karkarey R, Alcoverro T, Kumar S, Arthur R. Coping with catastrophe: foraging plasticity enables a benthic predator to survive in rapidly degrading coral reefs. Anim Behav 2017. [DOI: 10.1016/j.anbehav.2017.07.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
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15
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Murray CC, Mach ME, Martone RG, Singh GG, O M, Chan KMA. Supporting Risk Assessment: Accounting for Indirect Risk to Ecosystem Components. PLoS One 2016; 11:e0162932. [PMID: 27632287 PMCID: PMC5024992 DOI: 10.1371/journal.pone.0162932] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Accepted: 08/30/2016] [Indexed: 11/18/2022] Open
Abstract
The multi-scalar complexity of social-ecological systems makes it challenging to quantify impacts from human activities on ecosystems, inspiring risk-based approaches to assessments of potential effects of human activities on valued ecosystem components. Risk assessments do not commonly include the risk from indirect effects as mediated via habitat and prey. In this case study from British Columbia, Canada, we illustrate how such “indirect risks” can be incorporated into risk assessments for seventeen ecosystem components. We ask whether (i) the addition of indirect risk changes the at-risk ranking of the seventeen ecosystem components and if (ii) risk scores correlate with trophic prey and habitat linkages in the food web. Even with conservative assumptions about the transfer of impacts or risks from prey species and habitats, the addition of indirect risks in the cumulative risk score changes the ranking of priorities for management. In particular, resident orca, Steller sea lion, and Pacific herring all increase in relative risk, more closely aligning these species with their “at-risk status” designations. Risk assessments are not a replacement for impact assessments, but—by considering the potential for indirect risks as we demonstrate here—they offer a crucial complementary perspective for the management of ecosystems and the organisms within.
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Affiliation(s)
- Cathryn Clarke Murray
- Institute for Resources, Environment and Sustainability, University of British Columbia, Vancouver, British Columbia, Canada
- North Pacific Marine Science Organization (PICES), Sidney, British Columbia, Canada
- * E-mail:
| | - Megan E. Mach
- Institute for Resources, Environment and Sustainability, University of British Columbia, Vancouver, British Columbia, Canada
- Center for Ocean Solutions, Monterey, California, United States of America
| | - Rebecca G. Martone
- Center for Ocean Solutions, Monterey, California, United States of America
| | - Gerald G. Singh
- Institute for Resources, Environment and Sustainability, University of British Columbia, Vancouver, British Columbia, Canada
| | - Miriam O
- Fisheries & Oceans Canada, Institute for Ocean Sciences, Sidney, British Columbia, Canada
| | - Kai M. A. Chan
- Institute for Resources, Environment and Sustainability, University of British Columbia, Vancouver, British Columbia, Canada
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Barreto R, Ferretti F, Flemming JM, Amorim A, Andrade H, Worm B, Lessa R. Trends in the exploitation of South Atlantic shark populations. CONSERVATION BIOLOGY : THE JOURNAL OF THE SOCIETY FOR CONSERVATION BIOLOGY 2016; 30:792-804. [PMID: 26634410 DOI: 10.1111/cobi.12663] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2015] [Revised: 09/25/2015] [Accepted: 11/29/2015] [Indexed: 06/05/2023]
Abstract
Approximately 25% of globally reported shark catches occur in Atlantic pelagic longline fisheries. Strong declines in shark populations have been detected in the North Atlantic, whereas in the South Atlantic the situation is less clear, although fishing effort has been increasing in this region since the late 1970s. We synthesized information on shark catch rates (based on 871,177 sharks caught on 86,492 longline sets) for the major species caught by multiple fleets in the South Atlantic between 1979 and 2011. We complied records from fishing logbooks of fishing companies, fishers, and onboard observers that were supplied to Brazilian institutions. By using exploratory data analysis and literature sources, we identified 3 phases of exploitation in these data (Supporting Information). From 1979 to 1997 (phase A), 5 fleets (40 vessels) fished mainly for tunas. From 1998 to 2008 (phase B), 20 fleets (100 vessels) fished for tunas, swordfishes, and sharks. From 2008 to 2011 (phase C), 3 fleets (30 vessels) fished for multiple species, but restrictive measures were implemented. We used generalized linear models to standardize catch rates and identify trends in each of these phases. Shark catch rates increased from 1979 to 1997, when fishing effort was low, decreased from 1998 to 2008, when fishing effort increased substantially, and remained stable or increased from 2008 to 2011, when fishing effort was again low. Our results indicate that most shark populations affected by longlines in the South Atlantic are currently depleted, but these populations may recover if fishing effort is reduced accordingly. In this context, it is problematic that comprehensive data collection, monitoring, and management of these fisheries ceased after 2012. Concurrently with the fact that Brazil is newly identified by FAO among the largest (and in fastest expansion) shark sub-products consumer market worldwide.
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Affiliation(s)
- Rodrigo Barreto
- Departamento de Pesca e Aquicultura (DEPAq), Av. Dom Manoel de Medeiros, Universidade Federal Rural de Pernambuco (UFRPE), S/N, Recife, PE, 52171-900, Brazil
| | - Francesco Ferretti
- Hopkins Marine Station, Stanford University, Pacific Grove, CA, 93950, U.S.A
| | - Joanna M Flemming
- Department of Mathematics and Statistics, Dalhousie University, Halifax, NS, B3H 4R2, Canada
| | - Alberto Amorim
- Instituto de Pesca, Agência Paulista de Tecnologia dos Agronegócios da Secretaria de Agricultura e Abastecimento do Estado de São Paulo (APTA), Avenida Bartolomeu de Gusmão, 192, Santos, SP, 11045-401, Brazil
| | - Humber Andrade
- Departamento de Pesca e Aquicultura (DEPAq), Av. Dom Manoel de Medeiros, Universidade Federal Rural de Pernambuco (UFRPE), S/N, Recife, PE, 52171-900, Brazil
| | - Boris Worm
- Biology Department, Dalhousie University, Halifax, NS, B3H 4R2, Canada
| | - Rosangela Lessa
- Departamento de Pesca e Aquicultura (DEPAq), Av. Dom Manoel de Medeiros, Universidade Federal Rural de Pernambuco (UFRPE), S/N, Recife, PE, 52171-900, Brazil
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Graham F, Rynne P, Estevanez M, Luo J, Ault JS, Hammerschlag N. Use of marine protected areas and exclusive economic zones in the subtropical western North Atlantic Ocean by large highly mobile sharks. DIVERS DISTRIB 2016. [DOI: 10.1111/ddi.12425] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Affiliation(s)
- Fiona Graham
- Rosenstiel School of Marine and Atmospheric Science; University of Miami; 4600 Rickenbacker Causeway Miami FL 33149 USA
| | - Patrick Rynne
- Rosenstiel School of Marine and Atmospheric Science; University of Miami; 4600 Rickenbacker Causeway Miami FL 33149 USA
| | - Maria Estevanez
- Rosenstiel School of Marine and Atmospheric Science; University of Miami; 4600 Rickenbacker Causeway Miami FL 33149 USA
| | - Jiangang Luo
- Rosenstiel School of Marine and Atmospheric Science; University of Miami; 4600 Rickenbacker Causeway Miami FL 33149 USA
| | - Jerald S. Ault
- Rosenstiel School of Marine and Atmospheric Science; University of Miami; 4600 Rickenbacker Causeway Miami FL 33149 USA
| | - Neil Hammerschlag
- Rosenstiel School of Marine and Atmospheric Science; University of Miami; 4600 Rickenbacker Causeway Miami FL 33149 USA
- Leonard and Jayne Abess Center for Ecosystem Science and Policy; University of Miami; PO Box 248203 Coral Gables FL 33146 USA
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18
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Evolutionary theory as a tool for predicting extinction risk. Trends Ecol Evol 2015; 30:61-5. [PMID: 25578283 DOI: 10.1016/j.tree.2014.12.001] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2014] [Revised: 12/01/2014] [Accepted: 12/03/2014] [Indexed: 01/17/2023]
Abstract
Timely and proactive wildlife conservation requires strategies for determining which species are most at the greatest threat of extinction. Here, we suggest that evolutionary theory, particularly the concept of specialization, can be a useful tool to inform such assessments and may greatly aid in our ability to predict the vulnerabilities of species to anthropogenic impacts.
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Gallagher A, Orbesen E, Hammerschlag N, Serafy J. Vulnerability of oceanic sharks as pelagic longline bycatch. Glob Ecol Conserv 2014. [DOI: 10.1016/j.gecco.2014.06.003] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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