Francisco Javier Aznar

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• Dr
• Professor (Associate) at University of Valencia

Copepods of the genus Pennella parasitize a wide range of marine animals, including cetaceans, teleosts, and cephalopods worldwide. Their taxonomy is unclear, as there is incongruence between morphological and genetic data and incomplete species coverage. This study provides new morphological and genetic (COI) data from 23 specimens of Pennella cf....

Most research on cetacean swimming has been conducted on captive dolphins due to limited accessibility to wild cetaceans. Epibiotic barnacles have been used as indirect evidence of cetacean hydrodynamics, given their lifelong association with cetaceans and dependence on water flow. Previous studies suggested that the spatial distribution of the bar...

En el Mediterráneo occidental, el delfín listado, Stenella coeruleoalba, ha sufrido dos mortandades masivas bien documentadas causadas por morbillivirus en 1990 y 2007. El impacto poblacional de estas epidemias se desconoce, ya que las estimas de abundancia de delfines listados son escasas. Este trabajo investiga si dicho impacto podría investigars...

In the Northeast Atlantic, it is unclear whether short-finned pilot whales, Globicephala macrorhynchus (SFPWs), are transient or resident above 40ºN. We used Anisakis spp. to identify the latitudes recently visited by a SFPW pod stranded in NW Spain (43ºN) in 2020. Analysis of cox2 gene in 30 nematodes from 6 SFPWs revealed the presence of A. simpl...

Early juvenile loggerhead turtles (Caretta caretta) rely on gelatinous zooplankton, whereas individuals larger than 40 cm curved carapace length are adapted to crush hard-shelled invertebrates. Nevertheless, fish were reported to be the staple food of loggerhead turtles in the western Mediterranean 30 years ago. Here, the temporal consistency of su...

Cetaceans harbor multiple epibionts on their external surface, and these attach to particular microhabitats. Understanding what drives the selection of attachment sites is relevant for refining the use of epibionts as indicators of their hosts. We report on about 100 females of the mesoparasitic copepod Pennella balaenoptera attached to a dead Cuvi...

Conservation biology is a “crisis” discipline that investigates what, how, and why biotic elements in nature are to be conserved and/or restored. This goal is grounded on diverse values and narratives which are often justified on a scientific basis (a form of naturalistic fallacy), or simply implicitly assumed. When these values and narratives are...

Despite their high pathogenicity, limited knowledge is available on intrahost migration pathways and microhabitat distribution of pseudaliid lungworms. In this study, the distribution of Halocercus delphini in the lungs of the striped dolphin, Stenella coeruleoalba, was analyzed on three scales: between the right and left lungs, within the lungs, a...

Temporal and geographical changes in the infections of intestinal helminths of striped dolphins, Stenella coeruleoalba were investigated in waters off the Spanish Mediterranean coast based on a sample of 233 dolphins stranded during 1982-2016. The influence of host-related factors (length and sex) and seasonality was also examined. Four helminth sp...

The striped dolphin is the most abundant cetacean species in the Mediterranean, despite being vulnerable. It commonly harbors the ectoparasitic amphipod Syncyamus aequus, transmitted by contact between dolphins; the mesoparasitic copepod Pennella balaenoptera, with invertebrates as intermediate hosts and large teleosts and cetaceans as definitive h...

Whale lice (Cyamidae, 28 spp.) are amphipod ectoparasites found exclusively on cetaceans, where they feed on their epidermis and are transmitted by contact between hosts. Some cyamids typically parasitize a single host species, whereas others have been found on phylogenetically distant cetaceans. The drivers of this variable degree of host specific...

Metastrongyloid lungworms from the family Pseudaliidae infect the lungs and cranial sinuses of cetaceans worldwide, except Stenuroides herpestis, which exhibits a striking terrestrial association with the Egyptian mongoose, Herpestes ichneumon. Previous phylogenies of the Metastrongyloidea that included some (2-7) marine species of the Pseudaliidae...

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...

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, an...

The barnacle Xenobalanus globicipitis lives on the fins of at least 40 species of cetaceans. In striped dolphins, it is most abundant on the center and dorsal side of the caudal fin. The central third of the fin seems to generate greater vortical area with lower water velocity, which would favor larval attachment. The greater occurrence on the dors...

Find the publication, "Epibiotic Fauna on Cetaceans Worldwide: A Systematic Review of Records and Indicator Potential", in the following link: https://www.researchgate.net/publication/362233136_Epibiotic_Fauna_on_Cetaceans_Worldwide_A_Systematic_Review_of_Records_and_Indicator_Potential

Habitat connectivity in coral-reef ecosystems partly depends on fish movements, and considerable effort has been made to understand their temporal and spatial patterns of habitat use. In the Caribbean, the schoolmaster, Lutjanus apodus, typically settle and grow up in mangroves and seagrass beds, migrating later to coral reefs. However, direct sett...

Post‐mating courtship displays are often viewed as forms of sexual selection that allow individuals to assess fitness benefits from their mates based on honest signalling. However, display costs are not always easy to identify and quantify. Before each breeding attempt, male Black Wheatears Oenanthe leucura carry tens of heavy stones with the bill...

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 o...

The study of parasitism is of paramount importance from a health, veterinary and economic point of view. Not surprisingly, ‘parasitological’ subjects are typically included in the curriculum of various degrees involving human and veterinary medicine, via a descriptive treatment of contents, i.e., the identification, life cycle and pathology of the...

Aggressive behavior of bottlenose dolphins (Tursiops truncatus) towards conspecifics is widely described, but they have also often been reported attacking and killing harbour porpoises (Phocoena phocoena) around the world. However, very few reports exist of aggressive interactions between bottlenose dolphins and other cetacean species. Here, we pro...

We report on the emergence of the epibiotic barnacle Xenobalanus globicipitis in Guiana dolphins (Sotalia guianensis) from Sepetiba Bay, Rio de Janeiro, Brazil, in September 2018, six months after a lethal morbillivirus epidemic. Small boat surveys were conducted at the entrance and in the interior of the bay from January 2018 to February 2021. Dol...

The Antarctic minke whale, Balaenoptera bonaerensis Burmeister, 1867, is believed to migrate seasonally, feeding on krill in Antarctic waters during the austral summer and breeding in warmer Southern Hemisphere waters during the winter. The present review gathers evidence based on sightings (N=104 records), strandings (N=18), acoustics (N=3) and ca...

The Antarctic minke whale, Balaenoptera bonaerensis, makes seasonal migrations from low latitudes, where it spends the winter in breeding areas, to the Southern Ocean, where it feeds on krill during the austral summer. The seasonality or intraspecific variation of these migrations is still unknown; in fact, fin whales have been observed in Antarcti...

The commensal epibiont Xenobalanus globicipitis is found on the trailing edge of the fins of about 40 cetacean species worldwide. The ubiquity and high detectability of this epibiont has allowed for multiple records on swimming, stranded, and captured cetaceans. Also, the study of its biology has provided valuable information of its cetacean hosts....

Background Current data about Pseudaliidae show contrasting patterns of host specificity between congeneric species. We investigated how both contact and compatibility between hosts and parasites contributed to the patterns of lungworm infection observed in a community of five species of cetaceans in the western Mediterranean. Methods The lungs of...

Antarctic minke whales, Balaenoptera bonaerensis, typically inhabit waters of the Southern Hemisphere and migrate alone or in small groups to higher latitudes during the austral summer, where they feed on Antarctic krill. We examined the epibiotic macrofauna of 333 Antarctic minkes captured in the Indo-Pacific region of the Antarctic by a Japanese...

Xenobalanus globicipitis is an epibiont of cetaceans that typically attaches on the edge of fins. Recent evidence showed that its distribution on the tail flukes of striped dolphins, Stenella coeruleoalba, was non-random; most barnacles occurring on the dorsal side, and the central third, of the trailing edge of the flukes. These patterns were inte...

Cetaceans harbor a rich and high-specific parasite fauna that can influence hosts’ population dynamics and be used to unveil aspects on their biology. Furthermore, these biotic associations are interesting models to investigate coevolutionary processes in the marine environment. In this chapter, we select a digenean exclusive to cetaceans, Pholeter...

Members of the Torpedinidae (torpedoes) and Hypnidae (coffin ray) use electric organ discharges (EOD) to stun or kill their prey before consumption. We investigated whether EOD could also negatively affect the helminth larvae infecting these preys through a surrogate model: we applied electric discharges to individuals of blue whiting, Micromesisti...

Within the cetacean lungworm family Pseudaliidae Raillet & Henry, 1909, the distinction between the two genera of the subfamily Halocercinae Delamure, 1952, i.e. Halocercus Baylis & Daubney, 1925 and Skrjabinalius Delyamure, 1942, is principally based on the structure and shape of the male copulatory bursa. In species of Halocercus, the bursa is un...

We analyzed patterns of aggregation and spatial distribution of the epizoic barnacle Xenobalanus globicipitis on the flukes of Mediterranean striped dolphins, Stenella coeruleoalba, assessing its potential use as an indicator of the host's hydrodynamics based on data from 55 dolphins. Barnacles occurred along the trailing edge with the cirri orient...

The impact of inbreeding on fitness has been widely studied and provides consequential inference about the adaptive potential and the impact on survival for reduced and fragmented natural populations. Correlations between heterozygosity and fitness are common in the literature, but they rarely inform about the likely mechanisms. Here, we investigat...

The impact of inbreeding on fitness has been widely studied and provides consequential inference about adaptive potential and the impact on survival for reduced and fragmented natural populations. Correlations between heterozygosity and fitness are common in the literature, but they rarely inform about the likely mechanisms. Here, we investigate a...

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...

Sea turtles exploit a variety of habitats during their lifetime and are thus exposed to a number of anthropogenic threats, including interaction with fisheries. Mitigating this impact requires determining patterns of habitat use by turtles, which largely relies on data from marked individuals. We investigated the use of epibiotic barnacles as a cos...

A detailed list of acanthocephalans from Argentina was generated based on 205 published records. The list includes 52 named and 35 undetermined species of Acanthocephala infecting 6 species of invertebrate (2 amphipods, 3 decapods and 1 insect) and 155 species of vertebrate (one cartilaginous fish, 95 bony fishes, 10 amphibians, 3 reptiles, 13 bird...

Pseudaliid lungworms infect the lungs and sinuses of cetaceans. Information on the life cycle and epidemiology of pseudaliids is very scarce and mostly concerns species that infect coastal or inshore cetaceans. Available evidence indicates that some pseudaliids are vertically transmitted to the host, whereas others are acquired via infected prey. W...

Avian pox is a disease caused by Avipoxvirus spp. that is known to produce self-limiting, proliferative epithelial lesions in over 275 bird species from 70 families. Although generally benign, this emerging disease can sometimes provoke significant outbreaks of mortality. In rallids, there is a single serological record of Avipoxvirus. In this stud...

There are numerous reports of billfishes spearing objects, marine organisms, and even humans. Whether or not this behaviour is intentional and, if so, what is its functional meaning, are open questions. In 2016, an adult blue shark (Prionace glauca) was found to be killed by a juvenile swordfish (Xiphias gladius) in the western Mediterranean. Here...

In this study, 542 individual fish from 20 species from the Patagonian continental shelf of Argentina were examined for acanthocephalans. A total of 1,547 acanthocephalans belonging to 5 species were collected from 18 species of fish. Adult forms were represented by 2 species: Aspersentis johni ( Baylis, 1929 ) (Heteracanthocephalidae) from longtai...

Acanthocephalans display a two-host life cycle that involves arthropods as intermediate hosts and vertebrates as definitive hosts. Some species also use paratenic hosts to bridge the trophic gap between both obligatory hosts. However, the relative role of these paratenic hosts in the transmission to definitive hosts has seldom been assessed quantit...

Background Functional inference on the attachment of acanthocephalans has generally been drawn directly from morphology. However, performance of structures is often non-intuitive and context-dependent, thus performance analysis should be included whenever possible to improve functional interpretation. In acanthocephalans, performance analysis of at...

Anthropogenic marine debris is one of the major worldwide threats to marine ecosystems. The EU Marine Strategy Framework Directive (MSFD) has established a protocol for data collection on marine debris from the gut contents of the loggerhead sea turtle (Caretta caretta), and for determining assessment values of plastics for Good Environmental Statu...

We investigated Heterozygosity Fitness Correlations (HFC) for a marine mammal known to be subject to epizootic episodes, the striped dolphin (Stenella coeruleoalba). Dolphins included in the study varied with respect to their parasite burden of a highly pathogenic lung nematode (Skrjabinalius guevarai). Genetic diversity assessed for nuclear SNP lo...

Data on geographic distribution and life cycles of parasitic nematodes of the genus Anisakis in tropical oceanic regions are extremely scarce. Myctophids (lantern fishes) are a key component of mesopelagic trophic webs and could play a significant role in the transmission of Anisakis spp. in these regions. We examined Anisakis infections in a sampl...

Pennella balaenoptera is a mesoparasitic copepod that has been reported in at least 17 cetacean species. Subtle morphological differences in the first antennae of adult females have been used to discriminate this species from P. filosa, a species infecting fishes. Other morphological traits are unreliable because of their high plasticity, and no mo...

Gelatinous zooplankton, including jellyfish, ctenophores and pelagic tunicates, constitutes fragile marine animals that live in the water column, and represent an important resource for marine food webs through their seasonal pulses. Although there is scarce evidence on the occurrence of gelatinous zooplankton in stomach contents of apex, endotherm...

Background: At present, much research effort has been devoted to investigate overall ("average") responses of parasite populations to specific factors, e.g. density-dependence in fecundity or mortality. However, studies on parasite populations usually pay little attention to individual variation ("inequality") in reproductive success. A previous s...

Trophically-transmitted parasites are regularly exposed to potential new hosts through food web interactions. Successful colonization, or switching, to novel hosts, occur readily when ‘donor’ and ‘target’ hosts are phylogenetically related, whereas switching between distantly related hosts is rare and may result from stochastic factors (i.e. rare f...

Species of Corynosoma reported as adults in its typical hosts. Reports of adults in other host species are also included. Based on Aznar et al. [1], Dunagan and Miller [2], Amin [3], and references therein. (DOC)

List of definitive hosts and localities of Corynosoma australe Johnston, 1937. (DOC)

In September, 2016, an adult female blue shark (Prionace glauca) 247 cm long stranded alive on the coast of Valencia (Spain, Western Mediterranean) but died shortly afterwards. The necropsy revealed ongoing pregnancy, with 65 embryos in early stage of development, and a healthy condition with no signs of starvation. Two fishing hooks surrounded by...

Whale lice (Cyamidae) are ectoparasitic amphipods exclusive to cetaceans. Data on their epidemiology usually come from species infecting baleen whales, which are large, slow-moving hosts. In this study, we provide data on infection parameters, population structure and microhabitat selection in a whale louse exclusive to delphinids, Syncyamus aequus...

Background: Diseases associated to external parasitosis are scarcely reported in sea turtles. During the last decades several organism have been documented as a part of normal epibiont community connected to sea turtles. The copepod Balaenophilus manatorum has been cited as a part of epibiont fauna with some concern about its parasitic capacity. Th...

A recent stable isotope analysis of striped dolphins Stenella coeruleoalba stranded along the Spanish Mediterranean coast suggested a shift from a diet dominated by sardine Sardina pilchardus in 1990 towards a diet dominated by juvenile hake Merluccius merluccius in 2007-2008. This shift, apparently related to trophic cascade effects caused by over...

Species of Balaenophilus are the only harpacticoid copepods that exhibit a widespread, obligate association with vertebrates, i.e., B. unisetus with whales and B. manatorum with marine turtles and manatees. In the western Mediterranean, juveniles of the loggerhead sea turtle, Caretta caretta are the only available hosts for B. manatorum, which has...

Hatchling process of nauplii of Balaenophilus manatorum collected from hatchlings of loggerhead sea turtle, Caretta caretta. (MP4)

Comparative swimming performance of copepodite III (erratic) and copepodite V (directional) of Balaenophilus manatorum collected from hatchlings of loggerhead sea turtle, Caretta caretta. (MP4)

Measurements of body length and exopod of legs 2 (L2), 3 (L3) and 4 (L4), in μm (mean ± S.D. with range in parentheses), of five copepodite stages, and adult females and males, of Balaenophilus manatorum collected from hatchlings of loggerhead sea turtle, Caretta caretta. (DOCX)

Movement of antennulae, antennae and legs 2, 3 and 4 during swimming in copepodite V and adult of Balaenophilus manatorum collected from hatchlings of loggerhead sea turtle, Caretta caretta. (MP4)

We studied the phylogeography and historical demography of the most generalist digenean from cetaceans, Pholeter gastrophilus, exploring the effects of isolation by distance, ecological barriers and hosts’ dispersal ability on the population structure of this parasite. The ITS2 rDNA, and the mitochondrial COI and ND1 from 68 individual parasites we...

Worldwide distribution of Pholeter gastrophilus. Geographically distributed surveyed localities for P. gastrophilus. The number outside parentheses is the amount of individual cetacean species surveyed for P. gastrophilus; the number in parentheses is the number of infected dolphins; and the number in square brackets indicates the bibliographic sou...

Geographic coordinates of collection sites. Geographic coordinates of each collection site of Pholeter gastrophilus. (DOCX)

Reported prevalences of Pholeter gastrophilus within the distribution of the species. Prevalences of P. gastrophilus within the distribution of the species, including the number of infected hosts and the sampling size for each region. Note that the habitat of the host species is detailed. Complete references are at the end of the table. (XLSX)

Parasitism is an extraordinary life-strategy that largely influences that of most free-living organisms, including cetaceans. Parasites of cetaceans have a positive intrinsic and instrumental value, but also a potential pathogenic impact on host populations and, therefore, they should be considered in any biodiversity or conservation program. Yet,...

Black Wheatears (Oenanthe leucura) transport to breeding territories, including the nest, a large number of stones. Currently, there is negative evidence that stones serve for nest support, thermoregulation, weather protection or anti-predation, but in males, this behaviour appears to represent a form of post-mating display. This 'sexual selection'...

Adults of the acanthocephalan Corynosoma cetaceum deeply attach to the stomach of dolphins using the proboscis and its spiny foretrunk as a disk while the spiny hindtrunk bends to also embed its ventral spines. During deep attachment, two ventral folds of tegument, anterior and posterior, are created. Spine growth is inhibited to a variable degree...

Large oceanic sharks represent a suitable model to investigate the influence of a host's oceanic conditions on the structure of its helminth communities. In this study, we describe the intestinal helminth fauna, and investigate determinants of infracommunity structure, in 39 specimens of shortfin mako Isurus oxyrinchus collected in the NE Atlantic....

Background: Adults and larvae of generalist parasites are exposed to diverse hosts and local environmental conditions throughout their life cycles, thus local adaptation is expected to occur through phenotypic plasticity and/or natural selection. We investigated how the combined effect of cryptic host specificity and local selective pressures coul...

In this study we report on the helminth fauna of the invasive American red-eared slider Trachemys scripta in five localities from eastern Spain where this species co-occurs with two native, endangered freshwater turtles, i.e. Emys orbicularis and Mauremys leprosa. In total, 46 individuals of T. scripta were analysed for parasites. Adult individuals...

The highly specialized coronulid barnacle Xenobalanus globicipitis attaches exclusively on cetaceans worldwide, but little is known about the factors that drive the microhabitat patterns on its hosts. We investigate this issue based on data on occurrence, abundance, distribution, orientation, and size of X. globicipitis collected from 242 striped d...

Aquest volum recull les principals modalitats d'esport autòcton presents en el territori valencià a partir de les aportacions d'una trentena d'investigadors i investigadores de la Universitat i d'altres especialistes en divulgació popular. Catàleg de l'exposició pionera sobre la importància de l'esport tradicional valencià s'aborda especialment les...

The Western Mediterranean waters are frequently visited by leatherback turtles, Dermochelys coriacea, from the Atlantic populations. However, stranding events are rare in this area, and the study of every specimen is essential for gaining knowledge on different aspects of the biology of the species, particularly in aspects in which information is s...