Parasite community of Pagrus pagrus (Sparidae) from Rio de Janeiro, Brazil: evidence of temporal stability

Prevalence and molecular characterization of Hysterothylacium species infecting Pandora (Pagellus erythrinus) in the Mediterranean Sea of Egypt

Species of the genus Hysterothylacium are aquatic roundworms (nematodes) belonging to the family Raphidascarididae. Some species in this family are known to be associated with zoonotic diseases in humans after they consume their parasitic larvae in raw or undercooked fish. The aim of this research was to report the prevalence, morphology, and molecular characteristics of Hysterothylacium species in Pagellus erythrinus. A total of Two hundred fish were purchased from the fish market in Damanhour, Beheira Province, between December 2021 and November 2022 and subjected to examination. For molecular characterization, the internal transcribed spacer (ITS) region of nuclear ribosomal DNA and the mitochondrial cytochrome oxidase subunit 2 (COX-2) gene were used. Hysterothylacium species were morphologically described and identified from the intestine of Pagellus erythrinus in Beheira Province, Egypt. The PCR amplified 1087 bp and 629 bp of the target sequences of the ITS region and COX-2 gene, respectively. Sequence analysis revealed the Hysterothylacium thalassini species. The identified species provided novel biological data for the Hysterothylacium nematode in Pagellus erythrinus. The prevalence of Hysterothylacium species recovered from the intestine was 55%. The highest prevalence of 72% has been reported in summer compared to the lowest prevalence of 38% in the winter. Females had a higher prevalence of 61.8% than males, with 44.2%. The first detection, prevalence, and molecular characterization of H. thalassini in Pagellus erythrinus from Beheira Province, Egypt, was presented in this study.

Parasite communities of the golden snapper Lutjanus inermis (Perciformes: Lutjanidae): inter-annual variations during strange climatic events

Strange oceanographic events such as El Niño and La Niña may have indirect effects on the local transmission processes of intestinal parasites due to the reduction or increase in populations of potential intermediate or definitive hosts. A total of 713 individuals of Lutjanus inermis (Peters) were collected over an 8-year period (October 2015 to July 2022) from Acapulco Bay, Mexico. Parasite communities in L. inermis were quantified and analysed to determine if they experienced interannual variations in species composition and structure as a result of local biotic and abiotic factors influenced by oceanographic events, such as El Niño-Southern Oscillation (ENSO), or La Niña, the cool phase of the ENSO climate pattern. Twenty-six taxa of metazoan parasites were recovered and identified: two Monogenea, eight Digenea, two Acanthocephala, four Nematoda, one Cestoda, seven Copepoda, and two Isopoda. Species richness at the component community level (8 to 17 species) was similar to reported richness in other species of Lutjanus Bloch. Parasite communities of L. inermis exhibited high inter-annual variation in the abundance of component species of parasite. However, the species richness and diversity were fairly stable over time. Climatic episodes of El Niño and La Niña probably generated notable changes in the structure of local food webs, thus indirectly influencing the transmission rates of intestinal parasite species. Changes in species composition and community structure of parasites possibly were due to variations in feeding behaviour during the events and differences in the host body size.

Helminth Communities of Common Fish Species in the Coastal Zone off Crimea: Species Composition, Diversity, and Structure

In this paper, we analyzed the diversity and structure of helminth communities of 12 common fish species from the coastal zone of Crimea. A total of 53 helminth species were found. The total number of parasite species per host fish ranged from 3 to 18. Species richness at the infracommunity and component community levels were from 1.4-4.2 to 1.7-7, respectively. The Brillouin index for the infracommunites was 0.1-1, while the Shannon index for the component communities was 0.3-1.2. Component communities demonstrated a bi- or tri-modal distribution of the parasite prevalence and positive correlations between the prevalence and log-transformed abundance indices, thus following the "core-satellite" conception. Overall, the prevalence and abundance index of the dominant parasite in the component communities ranged from 18 to 80% and from 0.6 to 61.5 ind. per fish, respectively. The structure of the helminth component communities demonstrated good accordance with the nestedness mode where the rarest species occurred in the most diverse infracommunities, while the poorest infracommunities were composed of a few dominating species. More than two-thirds of the studied helminth species had an aggregated distribution indicating well-structured and developed communities. Our data provide a basis for further research and may be used for fish resource monitoring and management.

Parasites of Sardinella maderensis (Lowe, 1838) (Actinopterygii: Clupeidae) and Their Potential as Biological Tags for Stock Identification along the Coast of West Africa

This study is the first to provide information on the parasite fauna of Sardinella maderensis along the coasts of Benin and Ghana, and the first to investigate the potential use of parasites as biological tags in fish population studies in the area. It may thus serve as a starting point for upcoming studies. From February to June 2021, a total of 200 S. maderensis were sampled from the fishing port of Cotonou (Benin) and the Elmina landing site (Ghana). The prevalence and abundance of each parasite were recorded. The following are the outcomes of this study: Parasite species, such as Parahemiurus merus, Mazocraeoides sp. and Hysterothylacium fortalezae, were recorded along the coasts of Benin and Ghana, while Anisakis sp(p). and Tentacularia coryphaenae were only recorded along the coast of Benin. Parahemiurus merus was the most prevalent and abundant among all the parasites recorded. Anisakis sp(p). and T. coryphaenae were selected as having potential in the stock identification of S. maderensis. Both parasites were only recorded along the coast of Benin at a low prevalence. As a result, examinations of more S. maderensis from each location for these parasites may justify their use in stock identification studies.

Parasite communities and their ecological implications: comparative approach on three sympatric clupeiform fish populations (Actinopterygii: Clupeiformes), off Rio de Janeiro, Brazil

Fish parasite communities can be directly influenced by characteristics of host species. However, little is known about the host-parasite relationships in commercially important fish of the southeastern Atlantic. To address this knowledge gap, a comparative analysis of the parasite communities of three sympatric Clupeiformes was conducted. Cetengraulis edentulus (Engraulidae), Opisthonema oglinum (Clupeidae) and Sardinella brasiliensis (Clupeidae) were collected from an estuarine lagoon near Rio de Janeiro, Brazil. Prevalence, abundance and aggregation were estimated for infrapopulations; richness, diversity, evenness and dominance for infracommunities. The three component communities were compared using both quantitative and qualitative components. Canonical discriminant analysis was used to determine if a host population could be characterised by the component community of its parasites. Multivariate models revealed that host species, a proxy for diet and phylogenetic relationships, was the main factor influencing the composition of parasite infracommunities. Diet was found to be the main factor shaping the communities of endoparasites, in which digeneans were dominant and best indicator of host population. Ectoparasites (copepods, isopods and monogeneans) displayed strong host-specificity with some species restricted to a single host population. The similarity of the component communities of the two clupeid populations demonstrated the influence of host phylogeny. Parasite infracommunities exhibited low diversity and high dominance, with many taxa restricted to a single host species (specialists) and few occurring in more than one (generalists). Host phylogeny and by extension, diet, morphology and coevolution with parasites appear to be important factors in determining the host-parasite relationships of clupeiform fish in the southeastern Atlantic.

Euryhaliotrema dolichodrilus n. sp. and Euryhaliotrema mimulus n. sp. (Monogenoidea: Dactylogyridae) infecting the gill lamellae of porgies, Calamus spp. (Perciformes: Sparidae) from the Gulf of Mexico off Florida, U.S.A

Two new species of Euryhaliotrema Kritsky & Boeger, 2002 (Monogenoidea: Dactylogyridae) were described from the gill lamellae of porgies, Calamus spp. (Perciformes, Sparidae), collected from the Gulf of Mexico off Florida: Euryhaliotrema dolichodrilus n. sp. from littlehead porgy Calamus proridens Jordan & Gilbert (type host), knobbed porgy Calamus nodosus Randall and Caldwell, grass porgy Calamus arctifrons Good & Bean, sheepshead porgy Calamus penna (Valenciennes), and jolthead porgy Calamus bajonado (Bloch & Schneider); and Euryhaliotrema mimulus n. sp. from jolthead porgy. The two new species along with Euryhaliotrema amydrum Kritsky & Bakenhaster, 2011, Euryhaliotrema carbuncularium Kritsky & Bakenhaster, 2011, Euryhaliotrema carbunculus (Hargis, 1955) Kritsky & Boeger, 2002, Euryhaliotrema luisae Cruces, Chero & Luque, 2018, Euryhaliotrema magnopharyngis Cruces, Chero & Luque, 2018, and Euryhaliotrema spirulum Kritsky & Bakenhaster, 2011 appeared to form a subgroup of species that developed secondarily within Euryhaliotrema.

Diversity, consistency, and seasonality in parasite assemblages of two sympatric marine fish Pagrus pagrus (Linnaeus, 1758) and Pagellus bogaraveo (Brünnich, 1768) (Perciformes: Sparidae) off the coast of Algeria in the western Mediterranean Sea

Various host characteristics (i. e., feeding habits, geographic distribution) and habitat characteristics (i.e., seasonality) influence the structure of parasite assemblages. To compare the parasite assemblages of hosts representatives of two genera of the same fish family, simultaneously occupying a geographic region, and to examine if seasonal variations influence parasite occurrence and abundance, we examined the parasite assemblages of two sympatric marine fish, Pagrus pagrus (n = 308) and Pagellus bogaraveo (n = 315) off the coast of Algeria in the western Mediterranean. Specimens were collected during summer and autumn over three consecutive years (2014-2016). Parasite assemblages were high in species richness and abundance. We compiled an inventory of 40 parasite taxa, including ectoparasitic monogeneans and crustaceans, and endoparasitic trematodes, cestodes, acanthocephalans, and nematodes. Endoparasite taxa primarily consisted of adult gastro-intestinal parasites and long lived larval helminths. Information on the parasite community structure and seasonal variations in parasite populations of these two hosts from the Mediterranean is here provided. Observed patterns of composition, diversity, dominance, and similarity indicate an overall consistency in assemblage structure. Although each host species harbored distinct parasite communities, they shared a high proportion of parasite species suggesting similar use of a common local pool of parasites. However, most shared species did not contribute to structuring the assemblages. Seasonal patterns in parasite abundance were observed for both hosts, with peak prevalence, abundance, and diversity in autumn. Results suggest that, regardless of a common pool of parasites being available to sympatric species, several ecological filters over time, led to distinct, independent variations in the parasite assemblages in each species.

Interannual variation in the metazoan parasite communities of bigeye trevally Caranx sexfasciatus (Pisces, Carangidae)

Parasite communities in Caranx sexfasciatus were characterized and analyzed to determine any interannual variations in structure and/or species composition. In total, 422 C. sexfasciatus were collected from Acapulco Bay, Mexico, between May 2016 and March 2019. Thirty-two taxa of metazoan parasites were identified: five Monogenea, thirteen Digenea, one Acanthocephala, one Cestoda, three Nematoda, seven Copepoda, and two Isopoda. Monogeneans were the most frequent and abundant parasite species in all sampling years. Parasite species richness at the component community level varied significantly from 8 (May 2016) to 25 (March 2019) and was similar to previous reports for other species of Carangidae. The component communities and infracommunities in C. sexfasciatus were characterized by low parasite species numbers, low diversity, and dominance of a single species (the monogenean Neomicrocotyle pacifica). Parasite community structure and species composition varied between sampling years and climatic seasons. Seasonal or local fluctuations in some biotic and abiotic environmental factors probably explain these variations.

Contracaecum larvae: morphological and morphometric retrospective analysis, biogeography and zoonotic risk in the amazon

Abstract In Brazil there are several records of parasitic nematodes of fish with zoonotic potential, especially those belonging to the family Anisakidae. This study considers the morphology, morphometry and prevalence of Contracaecum in Astronotus ocellatus , fish consumed in the Amazon and sold as ornamental and it also performs a retrospective analysis of the diversity of fish with larvae of Contracaecum, in studies carried out in Brazil over a period of 90 years. 40 specimens of A. ocellatus were necropsied, and the nematodes were collected and fixed in 93 parts 70% ethyl alcohol, 5 parts formaldehyde, and 2 parts glacial acetic acid (AFA) for morphological analysis under light microscopy and scanning electron microscopy. Of the 40 fish collected during this work, 27 were parasitized by Contracaecum larvae with a total intensity of 150 larvae. Retrospective analysis of intermediate host diversity for Contracaecum larvae resulted in 16 orders, 49 families, 96 genera, 140 species and a hybrid morphotype. In the retrospective study, half of the fish were from freshwater, with the order Perciformes being the most representative, with 16 families, 30 genera and 37 species. In Brazil, the occurrence of larvae of Contracaecum in fish was reported in 15 of the 26 states, with Rio de Janeiro presenting the most information regarding fish harboring Contracaecum larvae.

Are different parasite guilds of Pagrus pagrus equally suitable sources of information on host zoogeography?

Metazoan parasite assemblages of Pagrus pagrus inhabiting the southwestern Atlantic were analysed with the aim of identifying the existence of different stocks and to comparatively assess the value of different parasite guilds as indicators of zoogeographical regions. A total of 186 fish was examined. Samples were obtained from three Brazilian and one Argentine localities, distributed in three different biogeographic districts of the Argentine Zoogeographical Province. Pagrus pagrus harboured 26 metazoan parasite species distributed in three guilds, ectoparasites (10 species), long-lived larval endoparasites and short-lived gastrointestinal endoparasites (eight species each). Prevalence and abundance values of the former two guilds allowed analysing them comparatively to assess their value as biological indicators of both host population structure and zoogeography. Results of analyses on long-lived parasites evidenced the existence of three stocks, one in the regions of Rio de Janeiro and Sao Paulo, other in southern Brazil (Rio Grande do Sul) and a third in northern Argentina (Mar del Plata), responding to the differential environmental conditions characteristic of three zoogeographical ecoregions. Ectoparasite assemblages exhibited significant differences between all pairs of samples, including those considered as a single stock according to data on persistent parasites. Assemblages of long-lived larval parasites are considered as better indicators for stock assessment purposes than ectoparasites, whose population parameters were variable temporally and heterogeneous at small spatial scales. The distributional variability of persistent parasites of P. pagrus along large scales provides valuable information to help defining robust biogeographical patterns, applicable to stock identification and fishery management of this species.

Anoplodiscus Sonsino, 1890 (Monogenea: Anoplodiscidae): a new Australian species, and the first African record from South African hosts

Species of Anoplodiscus Sonsino, 1890 were previously only known from host members of Sparidae. A new species, Anoplodiscus hutsonae n. sp. is proposed for museum specimens originally collected from species of Scolopsis Cuvier (Nemipteridae) off Heron Island and Lizard Island, Australia. Additionally, Anoplodiscus tai Ogawa, 1994 is synonymised with Anoplodiscus cirrusspiralis Roubal, Armitage & Rohde, 1983 due to a lack of support for differential characters, and Anoplodiscus richiardii is considered a species inquirenda. Anoplodiscus cirrusspiralis causes visible lesions on the skin and fins of its host, and may also contribute to poor food conversion rates in sparid aquaculture. Anoplodiscus cirrusspiralis has been recorded from cultured sparids in Australia, Japan, South Africa, and South Korea, and was implicated as a disease agent in fish from the former two countries. However, the discovery of A. cirrusspiralis on Chrysoblephus gibbiceps (Valenciennes), Ch. laticeps (Valenciennes) and Cymatoceps nasutus (Castelnau) in South Africa, ?Pagrus major (Temminck & Schlegel) in South Korea, and P. auratus (Forster) in Australia, New Zealand and Japan suggests that this species may have a wide distribution and low host-specificity within the Sparidae. In South Africa, A. cirrusspiralis was first encountered on a morbid C. nasutus and Ch. gibbiceps from two public aquaria in 2009 (Two Oceans Aquarium, Cape Town and uShaka Sea World, Durban, respectively). Additional material was collected from C. laticeps kept at an abalone farm in Hermanus that originated from Struisbaai on the South African south coast. Anoplodiscus cirrusspiralis is redescribed from the South African specimens. This is the first record of a member of Anoplodiscidae Tagliani, 1912 from Africa.

Annotated checklist of fish cestodes from South America

An exhaustive literature search supplemented by a critical examination of records made it possible to present an annotated checklist of tapeworms (Cestoda) that, as adults or larvae (metacestodes), parasitize freshwater, brackish water and marine fishes, i.e. cartilaginous and bony fishes, in South America. The current knowledge of their species diversity, host associations and geographical distribution is reviewed. Taxonomic problems are discussed based on a critical evaluation of the literature and information on DNA sequences of individual taxa is provided to facilitate future taxonomic and phylogenetic studies. As expected, the current knowledge is quite uneven regarding the number of taxa and host-associations reported from the principal river basins and marine ecoregions. These differences may not only reflect the actual cestode richness but may also be due to the research effort that has been devoted to unravelling the diversity of these endoparasitic helminths in individual countries. A total of 297 valid species, 61 taxa identified to the generic level, in addition to unidentified cestodes, were recorded from 401 species of fish hosts. Among the recognized cestode orders, 13 have been recorded in South America, with the Onchoproteocephalidea displaying the highest species richness, representing c. 50% of all species diversity. The majority of records include teleost fish hosts (79%) that harbour larval and adult stages of cestodes, whereas stingrays (Myliobatiformes) exhibit the highest proportion of records (39%) among the elasmobranch hosts. Fish cestodes are ubiquitous in South America, being mostly recorded from the Warm Temperate Southeastern Pacific (WTSP; 31%) for marine hosts and the Amazon River basin (45%) for freshwater ones. The following problems were detected during the compilation of literary data: (i) unreliability of many records; (ii) poor taxonomic resolution, i.e. identification made only to the genus or even family level; (iii) doubtful host identification; and (iv) the absence of voucher specimens that would enable us to verify identification. It is thus strongly recommended to always deposit representative specimens in any type of studies, including faunal surveys and ecological studies. An analysis of the proportion of three basic types of studies, i.e. surveys, taxonomic and ecological papers, has shown a considerable increase of ecological studies over the last decade.

Pseudorhabdosynochus sulamericanus (Monogenea, Diplectanidae), a parasite of deep-sea groupers (Serranidae) occurs transatlantically on three congeneric hosts (Hyporthodus spp.), one from the Mediterranean Sea and two from the western Atlantic

Little is known of the diversity of the monogenean parasites infesting deep-sea groupers, and there is even less information available about their geographic distributions within the ranges of their hosts. To improve our understanding of these host-parasite relationships we conducted parasitological evaluations of the deep-water Haifa grouper Hyporthodus haifensis from the southern Mediterranean off Tunisia and Libya. We collected more than one species of diplectanid monogeneans from this host, but among these only one dominant species was abundant. This proved to be morphologically very similar to Pseudorhabdosynochus sulamericanus Santos, Buchmann & Gibson, 2000, a species originally described from the congeneric host H. niveatus off Brazil and also recorded from H. niveatus and H. nigritus off Florida. Here, we conducted a morphological comparison between newly collected specimens and those previously deposited in museum collections by other authors. Further, we used COI barcoding to ascertain the specific identity of the three host species to better elucidate the circumstances that might explain the unexpectedly broad distribution of P. sulamericanus. We assigned our specimens from H. haifensis to P. sulamericanus primarily on the basis of morphological characteristics of the sclerotized vagina. We also noted morphological characteristics of eastern and western Atlantic specimens that are not clearly described or not given in previous descriptions and so prepared a redescription of the species. We confirmed, by COI barcoding, that no sister-species relationships were evident among the three hosts of P. sulamericanus. Our observation that P. sulamericanus infects unrelated host species with putatively allopatric distributions was unexpected given the very limited dispersive capabilities and the high degree of host specificity common to members of Pseudorhabdosynochus. This transatlantic distribution raises questions with regard to phylogeography and assumptions about the allopatry of Atlantic grouper species from the Americas and Afro-Eurasia. Here, we propose some hypothetical explanations for our findings.