152 research outputs found

    Phylogeny of recent billfishes (Xiphioidei)

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    Billfishes are genetically and morphologically distinct enough from scombroids to merit placement in a separate suborder, Xiphioidei. Two extant families are usually recognized: Xiphiidae (swordfish, Xiphias) and Istiophoridae, currently containing three genera, Istiophorus (sailfishes), Makaira (marlins), and Tetrapturus (spearfishes, white, and striped marlins). Phylogenetic analyses of molecular data from mitochondrial and nuclear gene sequences (mitochondrial control region, ND2, 12S, and nuclear MN 32 regions) show a different picture of relationships. Makaira is not monophyletic: blue marlin cluster with sailfish and placement of black marlin is unstable. Accepting the molecular phylogeny gives two possible classifications: (1) two genera: blue marlin + sailfish (as Istiophorus) and all the rest (as Tetrapturus), or (2) five genera: blue marlin (Makaira), sailfish (Istiophorus), black marlin (Istiompax), striped and white marlin (Kajikia), and four spearfishes (Tetrapturus). We prefer the latter possibility. There is no genetic evidence to support recognition of separate species of Atlantic and Indo-Pacific sailfishes or blue marlins. Atlantic white marlin, Kajikia albida (Poey, 1860) is closely related to Indo-Pacific striped marlin, Kajikia audax (Philippi, 1887). The four spearfishes are closely related: the three Atlantic species, longbill (Tetrapturus pfluegeri Robins and de Sylva, 1963), Mediterranean (Tetrapturus belone Rafinesque, 1810), and roundscale (Tetrapturus georgii Lowe, 1841), and the one Indo-Pacific species, shortbill (Tetrapturus angustirostris Tanaka, 1915). The roundscale is the most divergent of the spearfishes. A fifth putative Tetrapturus sp., the hatchet marlin clusters with roundscale Spearfish but these two species could not be differentiated in this analysis

    A Molecular Phylogeny Of The Remoras And Their Relatives

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    The Echeneoidea comprise three families of cosmopolitan tropical/subtropical marine fishes: the Echeneidae (remoras), Coryphaenidae (dolphin fishes), and Rachycentridae (cobia). Complete nucleotide sequences from the mitochondrial 12S rRNA, 16S rRNA, protein-coding ND2, and nuclear ITS-1 gene regions were used to reconstruct the phylogenetic history of these fishes. Parsimony, maximum likelihood, and Bayesian analyses of combined data sets resolved trees of similar topology. Congruent with evolutionary hypotheses based on larval morphology, a monophyletic Rachycentridae + Coryphaenidae was resolved with high support. Within a monophyletic Echeneidae, the subfamilies Echeneinae and Remorinae were monophyletic. In agreement with recent morphological analyses, the genus Remora was paraphyletic based on the position of Remorina albescens Temminck and Schlegel, 1850. Consistent resolution within the Remorinae using parsimony, maximum likelihood, and Bayesian inference was not achieved with the gene regions surveyed in this study

    An Investigation Of The Global Population Structure Of The Marlinsucker (Remora osteochir) Inferred From Mitochondrial Control Region DNA Sequence Analysis

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    Nucleotide sequences from the hypervariable mitochondrial control region were used to investigate phylogeographic structuring in the marlinsucker, Remora osteochir (Cuvier, 1829). Complete DNA sequences were isolated from 71 individuals collected from seven geographically distant sample locations (5 Atlantic and 2 Pacific). Analyses of molecular variance (AMOVA) and Phi st resolved significant levels of population structuring among collections from the Atlantic and Pacific oceans, whereas negligible levels of population structuring were resolved among collections from within the Atlantic or Pacific oceans. Cluster analysis of haplotypes based upon inter-haplotype divergences resolved two distinct evolutionary lineages, one composed of haplotypes that only occurred in the Atlantic, and one composed of haplotypes that occurred in both Atlantic and Pacific samples. Observations are consistent with vicariant isolation of Atlantic and Pacific marlinsucker, followed by geologically recent secondary colonization of the Atlantic from the Indian Ocean. Congruence between patterns of genetic differentiation between marlinsucker and their istiophorid hosts, particularly blue marlin, Makaira nigricans Lacepede, 1802, and sailfish, Istiophorus platypterus (Shaw, 1792), highlights the possibility that this symbiont\u27s phylogeography is ultimately governed by host dispersal

    Gulf of Mexico oil blowout increases risks to globally threatened species

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    Fourteen marine species in the Gulf of Mexico are protected by the US Endangered Species Act, the Marine Mammal Protection Act, and the Migratory Bird Treaty Act. As the British Petroleum oil spill recovery and remediation proceed, species internationally recognized as having an elevated risk of extinction should also receive priority for protection and restoration efforts, whether or not they have specific legal protection. Forty additional marine species-unprotected by any federal laws-occur in the Gulf and are listed as threatened on the International Union for Conservation of Nature's (IUCN) Red List. The Red List assessment process scientifically evaluates species' global status and is therefore a key mechanism for transboundary impact assessments and for coordinating international conservation action. Environmental impact assessments conducted for future offshore oil and gas development should incorporate available data on globally threatened species, including species on the IUCN Red List. This consideration is particularly important because US Natural Resource Damage Assessments may not account for injury to highly migratory, globally threatened species. © 2011 by American Institute of Biological Sciences. All rights reserved.published_or_final_versio

    Parasitic copepods from Egyptian Red Sea fishes: Bomolochidae Claus, 1875

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    © The Author(s) 2015 Open Access - This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The attached file is the published version of the article

    The Real maccoyii: Identifying Tuna Sushi with DNA Barcodes – Contrasting Characteristic Attributes and Genetic Distances

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    BACKGROUND:The use of DNA barcodes for the identification of described species is one of the least controversial and most promising applications of barcoding. There is no consensus, however, as to what constitutes an appropriate identification standard and most barcoding efforts simply attempt to pair a query sequence with reference sequences and deem identification successful if it falls within the bounds of some pre-established cutoffs using genetic distance. Since the Renaissance, however, most biological classification schemes have relied on the use of diagnostic characters to identify and place species. METHODOLOGY/PRINCIPAL FINDINGS:Here we developed a cytochrome c oxidase subunit I character-based key for the identification of all tuna species of the genus Thunnus, and compared its performance with distance-based measures for identification of 68 samples of tuna sushi purchased from 31 restaurants in Manhattan (New York City) and Denver, Colorado. Both the character-based key and GenBank BLAST successfully identified 100% of the tuna samples, while the Barcode of Life Database (BOLD) as well as genetic distance thresholds, and neighbor-joining phylogenetic tree building performed poorly in terms of species identification. A piece of tuna sushi has the potential to be an endangered species, a fraud, or a health hazard. All three of these cases were uncovered in this study. Nineteen restaurant establishments were unable to clarify or misrepresented what species they sold. Five out of nine samples sold as a variant of "white tuna" were not albacore (T. alalunga), but escolar (Lepidocybium flavorunneum), a gempylid species banned for sale in Italy and Japan due to health concerns. Nineteen samples were northern bluefin tuna (T. thynnus) or the critically endangered southern bluefin tuna (T. maccoyii), though nine restaurants that sold these species did not state these species on their menus. CONCLUSIONS/SIGNIFICANCE:The Convention on International Trade Endangered Species (CITES) requires that listed species must be identifiable in trade. This research fulfills this requirement for tuna, and supports the nomination of northern bluefin tuna for CITES listing in 2010

    Influence of environmental parameters on movements and habitat utilization of humpback whales (Megaptera novaeangliae) in the Madagascar breeding ground

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    © The Author(s), 2016. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Royal Society Open Science 3 (2016): 160616, doi:10.1098/rsos.160616.Assessing the movement patterns and key habitat features of breeding humpback whales is a prerequisite for the conservation management of this philopatric species. To investigate the interactions between humpback whale movements and environmental conditions off Madagascar, we deployed 25 satellite tags in the northeast and southwest coast of Madagascar. For each recorded position, we collated estimates of environmental variables and computed two behavioural metrics: behavioural state of ‘transiting’ (consistent/directional) versus ‘localized’ (variable/non-directional), and active swimming speed (i.e. speed relative to the current). On coastal habitats (i.e. bathymetry < 200 m and in adjacent areas), females showed localized behaviour in deep waters (191 ± 20 m) and at large distances (14 ± 0.6 km) from shore, suggesting that their breeding habitat extends beyond the shallowest waters available close to the coastline. Males' active swimming speed decreased in shallow waters, but environmental parameters did not influence their likelihood to exhibit localized movements, which was probably dominated by social factors instead. In oceanic habitats, both males and females showed localized behaviours in shallow waters and favoured high chlorophyll-a concentrations. Active swimming speed accounts for a large proportion of observed movement speed; however, breeding humpback whales probably exploit prevailing ocean currents to maximize displacement. This study provides evidence that coastal areas, generally subject to strong human pressure, remain the core habitat of humpback whales off Madagascar. Our results expand the knowledge of humpback whale habitat use in oceanic habitat and response to variability of environmental factors such as oceanic current and chlorophyll level.Funding was provided by Total Foundation to NeuroPSI, and by individuals and foundations to the WCS Ocean Giants Program

    Swordfish bill injury involving abdomen and vertebral column: case report and review

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    <p>Abstract</p> <p>Background</p> <p>Penetrating injuries of the abdomen and spinal canal that involve organic material of animal origin are extremely rare and derive from domestic and wild animal attacks or fish attacks.</p> <p>Case presentation</p> <p>In this case report we present the unique, as far as the literature is concerned, unprovoked woman's injury to the abdomen by a swordfish. There are only four cases of swordfish attacks on humans in the literature - one resulted to thoracic trauma, two to head trauma and one to knee trauma, one of which was fatal - none of which were unprovoked. Three victims were professional or amateur fishermen whereas in the last reported case the victim was a bather as in our case. Our case is the only case where organic debris of animal's origin remained in the spinal canal after penetrating trauma.</p> <p>Conclusions</p> <p>Although much has been written about the management of penetrating abdominal and spinal cord trauma, controversy remains about the optimal management. Moreover, there is little experience in the management of patients with such spinal injuries, due to the fact that such cases are extremely rare. In this report we focus on the patient's treatment with regard to abdominal and spinal trauma and present a review of the literature.</p

    Investigating Behaviour and Population Dynamics of Striped Marlin (Kajikia audax) from the Southwest Pacific Ocean with Satellite Tags

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    Behaviour and distribution of striped marlin within the southwest Pacific Ocean were investigated using electronic tagging data collected from 2005–2008. A continuous-time correlated random-walk Kalman filter was used to integrate double-tagging data exhibiting variable error structures into movement trajectories composed of regular time-steps. This state-space trajectory integration approach improved longitude and latitude error distributions by 38.5 km and 22.2 km respectively. Using these trajectories as inputs, a behavioural classification model was developed to infer when, and where, ‘transiting’ and ‘area-restricted’ (ARB) pseudo-behavioural states occurred. ARB tended to occur at shallower depths (108±49 m) than did transiting behaviours (127±57 m). A 16 day post-release period of diminished ARB activity suggests that patterns of behaviour were affected by the capture and/or tagging events, implying that tagged animals may exhibit atypical behaviour upon release. The striped marlin in this study dove deeper and spent greater time at ≥200 m depth than those in the central and eastern Pacific Ocean. As marlin reached tropical latitudes (20–21°S) they consistently reversed directions, increased swimming speed and shifted to transiting behaviour. Reversals in the tropics also coincided with increases in swimming depth, including increased time ≥250 m. Our research provides enhanced understanding of the behavioural ecology of striped marlin. This has implications for the effectiveness of spatially explicit population models and we demonstrate the need to consider geographic variation when standardizing CPUE by depth, and provide data to inform natural and recreational fishing mortality parameters
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