7 results on '"F. J. Aznar"'
Search Results
2. Epibiotic Fauna on Cetaceans Worldwide: A Systematic Review of Records and Indicator Potential
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S. Ten, J. A. Raga, and F. J. Aznar
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Global and Planetary Change ,Ocean Engineering ,Aquatic Science ,Oceanography ,Water Science and Technology - Abstract
Each individual cetacean is an ecosystem itself, potentially harboring a great variety of animals that travel with it. Despite being often despised or overlooked, many of these epizoites have been proven to be suitable bio-indicators of their cetacean hosts, informing on health status, social interactions, migration patterns, population structure or phylogeography. Moreover, epizoites are advantageous over internal parasites in that many of them can be detected by direct observation (e.g., boat surveys), thus no capture or dissection of cetaceans are necessary. Previous reviews of epizoites of cetaceans have focused on specific geographical areas, cetacean species or epibiotic taxa, but fall short to include the increasing number of records and scientific findings about these animals. Here we present an updated review of all records of associations between cetaceans and their epibiotic fauna (i.e., commensals, ecto- or mesoparasites, and mutualists). We gathered nearly 500 publications and found a total of 58 facultative or obligate epibiotic taxa from 11 orders of arthropods, vertebrates, cnidarians, and a nematode that are associated to the external surface of 66 cetacean species around the globe. We also provide information on the use as an indicator species in the literature, if any, and about other relevant traits, such as geographic range, host specificity, genetic data, and life-cycle. We encourage researchers, not only to provide quantitative data (i.e., prevalence, abundance) on the epizoites they find on cetaceans, but also to inform on their absence. The inferences drawn from epizoites can greatly benefit conservation plans of both cetaceans and their epizoites.
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- 2022
- Full Text
- View/download PDF
3. Epibiotic fauna of the Antarctic minke whale as a reliable indicator of seasonal movements
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S. Ten, K. Konishi, J. A. Raga, L. A. Pastene, and F. J. Aznar
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Multidisciplinary ,Animals ,Antarctic Regions ,Seasons ,Minke Whale - Abstract
Antarctic minke whales,Balaenoptera bonaerensis, breed in tropical and temperate waters of the Southern Hemisphere in winter and feed in Antarctic grounds in the austral summer. These seasonal migrations could be less defined than those of other whale species, but the evidence is scanty. We quantitatively describe the epibiotic fauna of Antarctic minke whales and explore its potential to trace migrations. Seven species were found on 125 out of 333 examined Antarctic minke whales captured during the last Antarctic NEWREP-A expedition in the Southern Ocean: the amphipodBalaenocyamus balaenopterae(prevalence = 22.2%), the copepodPennella balaenoptera(0.6%); three coronulid, obligate barnacles,Xenobalanus globicipitis(11.1%),Coronula reginae(8.7%),C. diadema(0.9%); and two lepadid, facultative barnacles,Conchoderma auritum(9.0%) andC. virgatum(0.3%). Species with prevalence > 8% exhibited a modest increase in their probability of occurrence with whale body length. Data indicated positive associations between coronulid barnacles and no apparent recruitment in Antarctic waters.All specimens ofX. globicipitiswere dead, showing progressive degradation throughout the sampling period, and a geographic analysis indicated a marked drop of occurrence where the minimum sea surface temperature is X. globicipitis, on whales in the Southern Ocean could evince seasonal migration. Future investigations on geographical distribution, growth rate, and degradation (forX. globicipitis) could also assist in timing whales’ migration.
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- 2022
4. Determinants of diversity and composition of the tapeworm fauna of blue sharks, Prionace glauca: a geographical and host-specificity analysis
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J. Penadés-Suay, A. E. Jarque-Rico, J. Tomás, and F. J. Aznar
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Animal Science and Zoology ,Parasitology ,General Medicine - Abstract
Blue sharks, Prionace glauca, are cosmopolitan, extremely vagile sharks and the species among elasmobranchs for which most surveys containing tapeworm community data are available worldwide. In this study we report on the tapeworm fauna of three samples of blue sharks (n = 37) from two new regions (one sample from Galicia, north-east Atlantic, and two from Valencia, western Mediterranean), and compared it with previous studies, assessing the relative role of the ecological and evolutionary factors in structuring local tapeworm assemblages. Nine cestode taxa were identified, of which four included adult specimens, that is, Platybothrium auriculatum, Prosobothrium armigerum, Anthobothrium caseyi and Molicola horridus. The abundance of these species, and Brillouin's diversity index, differed significantly among samples without a clear geographical signal. A comparison with six previous surveys revealed that tapeworm assemblages were composed of the same ‘core’ taxa, with mean species richness typically ranging from two to four species. Global records of adult tapeworms in blue sharks included: 15 taxa identified at species level, of which only eight (generalist trypanorhynchs) were shared with other sympatric host species; five mostly with other carcharhinids; and three with large lamnid sharks sharing the blue sharks’ habitat. The composition of tapeworm communities of blue sharks is thus highly constrained by strong host specificity, with composition and abundance varying across localities depending on idiosyncratic environmental conditions.
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- 2022
- Full Text
- View/download PDF
5. Recent increase of ulcerative lesions caused by
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C, Pons-Bordas, A, Hazenberg, A, Hernandez-Gonzalez, R V, Pool, P, Covelo, P, Sánchez-Hermosin, A, López, C, Saavedra, N, Fraija-Fernández, M, Fernández, and F J, Aznar
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Electron Transport Complex IV ,Dolphins ,Stomach ,Prevalence ,Animals ,Anisakiasis ,Atlantic Ocean ,Anisakis ,Ulcer - Abstract
Species of Anisakis typically infect the stomach of cetaceans worldwide, often causing ulcerative lesions that may compromise the host's health. These nematodes also cause anisakiasis or allergic reactions in humans. To assess the risks of this emerging zoonosis, data on long-term changes in Anisakis infections in cetaceans are necessary. Here, we compare the prevalence and severity of ulcerative lesions caused by Anisakis spp. in five cetacean species stranded along the north-west Spanish coast in 2017-2018 with published data from 1991-1996. Open ulcers were found in 32/43 short-beaked common dolphins, Delphinus delphis; 3/5 striped dolphins, Stenella coeruleoalba; 1/7 bottlenose dolphins, Tursiops truncatus; and 1/3 harbour porpoises, Phocoena phocoena meridionalis; a single individual of long-finned pilot whale, Globicephala melas, was found uninfected. In common dolphins, the mean abundance of open ulcers per host was 1.1 (95% confidence interval: 0.8-1.3), with a maximum diameter (mean ± standard deviation) of 25.4 ± 16.9 mm. Stomachs with scars or extensive fibrosis putatively associated with Anisakis were detected in 14 and five animals, respectively. A molecular analysis based on the mitochondrial cytochrome c oxidase II gene using 18 worms from three cetacean species revealed single or mixed infections of Anisakis simplex sensu stricto and Anisakis pegreffii. Compared with the period 1991-1996, we found a strong increase of prevalence, abundance and extension of ulcerative lesions in most cetacean species. Anisakis populations could have increased in the study area over the last decades, although we cannot rule out that a higher environmental stress has also boosted the pathological effects of these parasites.
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- 2020
6. Constructional morphology and mode of attachment of the trunk of Corynosoma cetaceum (Acanthocephala: Polymorphidae)
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F J, Aznar, A O, Bush, M, Fernández, and J A, Raga
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Male ,Dolphins ,Muscles ,Stomach ,Microscopy, Electron, Scanning ,Animals ,Female ,Acanthocephala ,Host-Parasite Interactions - Abstract
Dead specimens of Corynosoma cetaceum were used to describe the trunk musculature of this species and to infer the use of the trunk as a secondary holdfast. Inferences were based on trunk muscle arrangement, changes in trunk shape, size and distribution of spines, and geometry of tegument thickness. The foretrunk of C. cetaceum is swollen and forms a spiny disk that is bent ventrally. The disk is flattened by several groups of muscles not described previously, which seem able to finely adjust the disk surface over the substratum. Disk attachment appears to be accomplished by two dorsal neck retractor muscles specialized in pulling the anchored proboscis into the foretrunk. This mechanism has been described in other acanthocephalans, becoming surprisingly efficient when used with a flattened, armed foretrunk. The ventrally spined hindtrunk requires force to move downwards in order to attach. A single ventral neck retractor muscle seems specialized in pulling the posterior trunk forward, inducing a downward force due to the muscle's precise points of insertion. This mechanism necessarily generates ventral wrinkling that needs to be eliminated for the spiny surface to be functional. The trunk ventral muscles are apparently arranged so as to concentrate the "excess" of the tegument into a single fold, optimizing the use of the remaining surface for attachment. The size and distribution of spines, as well as the geometry of tegumental thickness, conform to these observations. Morphological changes, seemingly simple, such as structural bending, may have triggered a cascade of subtle modifications and new functions during acanthocephalan evolution, reflecting how morphological integration and novelty interact.
- Published
- 1999
7. Gastrointestinal helminths of loggerhead turtles (Caretta caretta) from the western Mediterranean: constraints on community structure
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F J, Aznar, F J, Badillo, and J A, Raga
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Intestines ,Fish Diseases ,Spain ,Helminths ,Stomach ,Fishes ,Mediterranean Sea ,Prevalence ,Animals ,Helminthiasis, Animal ,Intestinal Diseases, Parasitic ,Turtles - Abstract
Richness and composition of gastrointestinal helminth communities of 54 loggerhead turtles, Caretta caretta, from the western Mediterranean were interpreted from patterns of helminth exchange at 2 host taxonomic scales: exchange between marine turtles and other marine hosts and exchange within turtles. We predicted exchange of the former to be unimportant ecologically and evolutionarily because of the host phylogenetic distance. The absence of records of successful exchange at this host taxonomic scale confirmed that host physiological barriers seem to prevent contemporary parasite transfer between marine turtles and other sympatric hosts. Marine turtles also seem to exhibit an evolutionary association with their parasites largely independent from that of other marine hosts. Therefore, the composition of gastrointestinal helminth communities of marine turtles is predictably restricted to digeneans, nematodes, and aspidogastreans specific to these reptiles. At the scale of host species, helminth exchange among marine turtle species was expected to be significant. This was suggested by reports indicating a high proportion of parasites common to all sea turtle species. Mediterranean C. caretta harbored only 4 digenean species typical of marine turtles, and immature individuals of 1 digenean species accidentally acquired. Further, no relevant parasite exchange with other marine turtles was expected to occur because C. caretta is the only sea turtle species abundant in the western Mediterranean. Therefore, a predictable composition coupled with low species richness in infracommunities might be accounted for partly by constraints on parasite acquisition at both host scales. Host factors limiting parasite recruitment (mainly ectothermy and a wandering behavior) may also contribute to depauperate and isolationist infracommunities.
- Published
- 1998
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