Fish Parasites

Many species of fish in the world are infected with digenean trematodes belonging to the genera Clinostomum and Euclinostomum. In this study metacercariae, identified as Euclinostomum sp. on the basis of morphological characteristics and molecular data, were taken from 3 osphronemid fish Trichopsis vittata, T. schalleri, and Betta imbellis, in Thailand. Phylogenetic analysis based on a mitochondrial gene (cytochrome c oxidase subunit I) and 2 nuclear genes (18S rDNA and ITS1-internal transcribed spacer 1) of these Euclinostomum parasites indicated a clear distinction from those belonging to the Clinostomum genus. These are the first records of partial mitochondrial and nuclear DNA sequences of an Euclinostomum sp.

Lecithocladium angustiovum is identified from the stomach (87.33%) and the intestine (12.67%) of Indonesian short mackerel (Rastrelliger brachysoma). The description includes an elongated body; a mean total length of 1018.84 µm; and an ecsoma of 47.52% of the total length. The oral and ventral sucker ratio is 1:0.63, and the pharynx length is 97.42 µm. The sequence results were obtained by 18s rDNA gene sequencing of the 354 basepair (bp) DNA segment, and the mean base composition (%) was 17.7 A; 35.7 T; 29.6 G; and 17.1 C. A phylogenetic tree was constructed to demonstrate the genetic distance between L. angustiovum and sequences from Lecithocladium excisum, Dinurus longisinus, Plerurus digitatus and Lecithochirium caesionis obtained from GenBank.

O presente trabalho teve por objetivo avaliar relação parasita hospedeiro em tainhas (Mugil gaimardianus) parasitadas pelo copépodo Ergasilus versicolor. Os peixes foram capturados nos estuários da região de Bragança, nordeste paraense, entre os meses de agosto de 2006 e julho de 2007. Das 60 tainhas capturadas, apenas 13 não estavam infestadas, os 47 indivíduos restantes apresentaram um total de 1187 parasitas, o que resultou em 78,33% de prevalência, 25,55±39,2 de intensidade média e 19,7 de abundância. Esse é o primeiro relato dessa espécie de parasita em peixes do litoral do Pará. Palavras-chave.

The current study aims to evaluate the host/parasite ratio in Mugil gaimardianus parasitized by Ergasilus versicolor and its seasonality. Fish were caught in the estuaries of Bragança, Pará-Brazil, between August 2006 and July 2007. Sixty mullets were captured, but only 13 were not infested, and the other forty-seven specimens held a total of 1,187 parasites. It resulted in a prevalence of 78.33%, 25.55 ± 39.2 of mean intensity and abundance of 19.7. It is the first record of this parasite in Pará State.

In the present study, a tetraphylleadean larval cestode Scolex pleuronectis Müller, 1788 was determined in the intestine of shore rockling Gaidropsarus mediterraneus, Atlantic horse mackerel Trachurus trachurus, blotched picarel Spicara flexuosa, grass goby Zosterissesor ophiocephalus and round goby Neogobius melanostomus. Fish were collected by commercial fishermen in Sinop coasts of the Black Sea in April and May 2014. Infection prevalence and mean intensity values were determined as 12.5% and 2.00 ± 0.0 in shore rockling; 4.76% and 1.00 ± 0.0 in Atlantic horse mackerel; 20.0% and 6.80 ± 3.20 in botched picarel; 20.00% and 4.00 ± 0.0 in grass goby and, 1.44% and 55.00 ± 0.0 in round goby. Our results showed that this parasite species can be found widely at its larval stage in many bony fish species in the Black Sea.

This study focuses on the phylogenetic relationships within the Polyopisthocotylea and Monopisthocotylea, two groups that are often grouped within the monogeneans, a group of disputed paraphyly. Phylogenetic analyses were conducted with multiple outgroups chosen according to two hypotheses, a paraphyletic Monogenea or a monophyletic Monogenea, and with three methods, namely maximum parsimony, neighbour joining and maximum likelihood. Sequences used were from the partial domain C1, full domain D1, and partial domain C2 (550 nucleotides, 209 unambiguously aligned sites) from the 28S ribosomal RNA gene for 16 species of monopisthocotyleans, 26 polyopisthocotyleans including six polystomatids, and other Platyhelminthes (61 species in total, 27 new sequences). Results were similar with outgroups corresponding to the two hypotheses. Within the Monopisthocotylea, relationships were: {[(Udonella, capsalids), monocotylids], (diplectanids, ancyrocephalids)}; each of these families was found to be monophyletic and their monophyly was supported by high bootstrap values in neighbour joining and maximum parsimony. Within the Polyopisthocotylea, the polystomatids were the sister-group of all others. Among the latter, Hexabothrium, parasite of chondrichthyans, was the most basal, and the mazocraeids, mainly parasites of clupeomorph teleosts, were the sister-groups of all other studied polyopisthocotyleans, these, mainly parasites of euteleosts, being polytomous.

Rello-Yubero, Francisco Javier; Adroher-Auroux, Francisco Javier; Valero-López, Adela. 2004. An. la Real Acad. Ciencias Vet. Andalucía Orient. 17, 173–198.
Prólogo. Hasta hace poco más de una década, en España no se podía sospechar que algu-nos pescados tradicionales, básicos en la dieta de los españoles, pudieran ser los res-ponsables de graves alteraciones digestivas y alérgicas. Estas patologías están provoca-das por las fases larvarias de ciertos nematodos, llamados anisákidos, con un ciclo de vida marino complejo, en el que distintos mamíferos marinos (focas, ballenas, delfines,...) actúan como hospedadores definitivos, interviniendo además en este ciclo gran variedad de peces, cefalópodos y crustáceos. El hombre sólo se infecta al ingerir accidentalmente larvas vivas de estos nematodos, actuando como un hospedador accidental no óptimo, pues en él no se desarrollan los nematodos adultos. Aunque en España son recientes las primeras denuncias de anisakidosis huma-na, se trata de una parasitación muy estudiada en Japón y Holanda, debido a sus pecu-liares hábitos alimentarios, en los que el consumo de pescado crudo, ahumado o con un tratamiento térmico insuficiente, está muy arraigado. Esto no quiere decir que, anterior-mente, en nuestro país no se diera este tipo de parasitación, sino que no ha sido reco-nocida al confundirla con otros desórdenes gastrointestinales que cursan de manera similar y que conducían a diagnósticos poco precisos en cuanto a su etiología. A un diagnóstico más certero hay que añadir la incorporación a la dieta de platos exóticos preparados con pescado crudo o semicrudo para comprender el aumento del número de casos denunciados en nuestro país. El ciclo de vida de estos parásitos aún no está completamente dilucidado, pero cada vez son más los estudios que implican a un mayor número de hospedadores vertebrados e invertebrados en el mismo. En nuestro país existen un gran número de especies de peces comerciales que pueden actuar como vehículos de transmisión al hombre, entre las que cabe destacar la bacaladilla, la merluza y el boquerón.

Three opisthomonorchiinae species are described from fishes obtained at the Fish Market in Nouméa, New Caledonia. Opisthomonorchis dinema n. sp. from Carangoides dinema Bleeker differs from the other recognised species in the genus by the long recurved genital atrium, arcing anteriorly. Also described are Opisthomonorchis carangis Yamaguti, 1952 from Carangoides sp. and Pseudopisthomonorchis thapari (Varma & Singh, 1979) n. comb. for Opisthomonorchis thapari Varma & Singh, 1979 from Carangoides chrysophrys (Cuvier). The features distinguishing
Opisthomonorchis Yamaguti, 1952 and Pseudopisthomonorchis Madhavi, 1974 are discussed.

An outbreak recorded in Tilapia farms in Kafrelsheikh governorate with high mortalities ranged between 30-70 % in the summer season of 2014. This study was conducted for isolation and identification of the causative agent responsible for mortalities in four fish farms. Twelve Aeromonas isolates were identified by PCR using Aeromonas species primer at the molecular weight of (953 bp) then all strains were also confirmed by PCR as Aeromonas hydrophila using Aeromonas hydrophila specific-16S rRNA gene primer at the molecular weight of (103 bp).

Recent invasion theory has hypothesized that newly established exotic species may initially
be free of their native parasites, augmenting their population success. Others have hypothesized
that invaders may introduce exotic parasites to native species and/or may become hosts to native parasites
in their new habitats. Our study analyzed the parasites of two exotic Eurasian gobies that were
detected in the Great Lakes in 1990: the round goby Apollonia melanostoma and the tubenose goby Proterorhinus
semilunaris. We compared our results from the central region of their introduced ranges in
Lakes Huron, St. Clair, and Erie with other studies in the Great Lakes over the past decade, as well as
Eurasian native and nonindigenous habitats. Results showed that goby-specific metazoan parasites were
absent in the Great Lakes, and all but one species were represented only as larvae, suggesting that adult
parasites presently are poorly-adapted to the new gobies as hosts. Seven parasitic species are known to
infest the tubenose goby in the Great Lakes, including our new finding of the acanthocephalan Southwellina
hispida, and all are rare. We provide the first findings of four parasite species in the round goby and
clarified two others, totaling 22 in the Great Lakes—with most being rare. In contrast, 72 round goby
parasites occur in the Black Sea region. Trematodes are the most common parasitic group of the round
goby in the Great Lakes, as in their native Black Sea range and Baltic Sea introduction. Holarctic trematode
Diplostomum spathaceum larvae, which are one of two widely distributed species shared with Eurasia,
were found in round goby eyes from all Great Lakes localities except Lake Huron proper. Our study
and others reveal no overall increases in parasitism of the invasive gobies over the past decade after
their establishment in the Great Lakes. In conclusion, the parasite “load” on the invasive gobies appears
relatively low in comparison with their native habitats, lending support to the “enemy release
hypothesis.”

We announce, for the first time in Algeria the Digeneans Aphallus tubarium, Derogenes varicus, Derogenes latus, Lecithocladium excisum, Opeceloides furcatus,
Poracanthium furcatum, Proctoeces maculatus, Aponorus laguncula, Lasiotocus mulli, Proctotrema bacilliovatum and Holorchis legendrei parasites of Mullus surmuletus. This
parasitical investigation was carried out between December 2005 and April 2007 on red mullet from Oran, Annaba and National Park of El Kala coastal waters. Some samplings
also concerned specimens from the local fishermen gill-netting. A total of 170 M.surmuletus was investigated.

Adroher-Auroux, F.J., Benítez-Rodríguez, R., 2020. Res. Vet. Sci. 132, 535–545. https://doi.org/10.1016/j.rvsc.2020.08.003Anisakiasis or anisakiosis is a human parasitic infection caused by the third-stage larvae (L3) of nematodes of the genus Anisakis, although the term is also used in medical literature for the much less frequent (<3% of cases) infection by L3 of other genera of anisakids, particularly Pseudoterranova. These parasites have a marine lifecycle. Humans are infected by the L3 through ingesting of fish and squid, the intermediate/paratenic hosts. The live larvae generally penetrate the wall of the stomach or intestine causing, among other symptoms, intense pain or allergic symptoms. These are emerging, cosmopolite illnesses. Diagnosis and treatment is usually by endoscopy and extraction and identification of the larvae. Allergic forms are usually diagnosed by prick-test and/or allergen-specific IgE detection and treated with a suitable anti-allergy treatment. The patient is also warned against further consumption of marine fish or squid, as these may be infected with Anisakis. The most common method of prevention is thermal treatment of the entire fish or squid prior to consumption (>60 °C, >1 min or − 20 °C, >24 h). Useful measures for the control of anisakiasis would be to establish a national register of cases, to initiate educational campaigns for the general public and consciousness-raising and training campaigns for health professionals. These would be complemented by control measures for the relevant sectors of the economy: fish operators, fish farming, fishermen, fishmongers, fish industry and catering facilities. Possible genetic predisposition for allergy to Anisakis and the possible relationship between anisakiasis and cancer would also require further investigation.

This is a review of a 10 years investigation on the parasites of freshwater and marine fishes within the National ParK of El Kala located in the North-West of Algeria reporting the presence of Myxidium giardi, Ichthyophthirius multifiliis, Trichodina anguillae, Myxobolus exiguus, Trichodina sp., Dactylogyrus sp., Gyrodactylus sp., Khawia armeniaca, Neoechinorhynchus agilis, Acanthogyrus (Acanthosentis) maroccanus, Bothriocephalus claviceps, Bothriocephalus acheilognathi, Ligula intestinalis, Anguillicola crassus, Ergasilus sp, Argulus sp., Lernaea sp. and glochidia of Margaritana margaritifera in freshwater fishes of Lake Oubeira. In Mellah Lagoon the folowing parasites are reported in their hosts;
Dicentrarchus Labrax and D.punctatus : Myxobolus sp, Diplectanum aequans, Microcotyle sp, Acanthostomum imbutiforme, Ergasilus lizae and Caligus minutus.
Sparus aurata : Microcotyle chrisophrii.
Mugil cephalus and Liza aurata : Nerocila orbignyi.
Anguilla anguilla : Dactylogurus sp., Bucephalopsis sp. and Deropristis sp.,
Bothriocephalus claviceps, et Anguilicola crassus.

Objective: Seahorses (Familia: Syngnathidae), 3 species (Hippocampus hippocampus, Hippocampus guttulatus and Hippocampus fuscus) of which inhabit Turkey’s seas, are included in vulnerable or data deficient categories by IUCN. This lack of information makes better understanding of the current and future status of these species more difficult. For this purpose, touching upon the different aspects of these species will yield a better view for consideration. To serve this aim, studies about pathogens and diseases of seahorses were examined for this compilation study.
Methods: In this compilation, scientific studies about pathogens and diseases of the world’s seahorses have been compiled. Tissues, organs, pathogens and diseases involved have been briefly touched upon and underlined. According to the results of literature research, there is no such study in Turkey and also few international studies were encountered.
Results and Discussion: During the research for related sources, studies about the pathogens and diseases of seahorses and many general references were found. According to the results of the scientific studies, diseases like hyperplasy, tail rot disease, necrotic foci in kidneys and liver, sloughing of epidermis, depigmentation of skin, white necrotic tail tips, gas bubble formation, external gas bubble formation, deep skin ulceration and white patch disease were identified from seahorses. These disease causing effects and organisms were categorized as microbiological, parasitological and physically. Tissues and organs like mouth epithelium, liver, heart, blood, digestive tract, gut wall, body cavity, stomach, intestine, trunk, operculum, bile duct and gallbladder were showing the effects of these diseases. Studies about the pathogens of seahorses are needed in Turkey. By responding this need, more data related with the health of natural and cultural seahorse populations, would be collected. Also this compilation will serve to better understanding of biodiversity in Turkey and contribute to the possible future conservation biology studies.
Keywords: Hippocampus sp., seahorse, pathogen, biodiversity, conservation biology.

We announce, for the first time in Algeria in Anguilla anguilla the presence of and glochidies of the bivalve Anodonta (Mollusca). This investigation on the biodiversity of the parasitofauna of eel was carried out between October 2006 and September 2007 in the National Park of El Kala (Northeastern Algeria) at 2 mixo-oligohaline lakes: Lac Tonga (2700 ha) and Lac 0ubeira (2200 ha) and at a brackish lagoon Lac El Mellah (865 ha). On the whole 375 eels were sampled (LT = 24,2-71,6 cm; Weight 22,5-791,3g). The sampled body parts were the skin, the fins, the gills, the stomach, the intestine and the swimbladder.

On the new investigation of some Trematode fauna of Arabian Gulf fishes, Monascus sp. a digenea parasite of pampus argenteus and Helicometrina nimia of greasy grouper, Epinephelus tauvina are register. Fish specimens were collected during the year 2016. A description of the studied specimens, besides comments concerning its taxonomic status, the morphological characters and measurements of the present material of Monascus sp. The Monascus sp. parasite are described on the present study compared with some measurements of Nine nominal species have been reported in the genus Monascus up to 1993 and showing that similarity with M. filiformis and differ in the size of parasite. The results indicated that the parasites are considered as having new hosts viz, p. argenteus and as new records in the Iraqi marine fishes. In the present study, a new host and a new host locality are presented for the two species. The taxonomic status of members of Helicometrina has been questionable, the validity of diagnostic features, especially in regard to the number of testes. In the present study, specimens presented a permanent and steady number of testes (n=9) and therefore its use as a diagnostic character and is very similar with Linton (1910). Epinephelus tauvina is considered a new host for Helicometrina nimia, and Northwest Arabian Gulf a new locality for the species.

This study reviews the effects of parasites of fresh water fish hosts. Like other living organisms, fish harbour parasites either external or internal which cause a host of pathological debilities in them. The parasites live in close obligate association and derive benefits such as nutrition at the host’s expense, usually without killing the host. They utililize energy otherwise available for the hosts growth, sustenance, development, establishment and reproduction and as such may harm their hosts in a number of ways and affect fish production. The common parasites of fishes include the unicellular microparasites (viruses, bacteria, fungi and protozoans). The protozoans i.e. microsporidians and mixozoans are considered in this review. The multicellular macroparasites mainly comprised of the helminthes and arthropods are also highlighted. The effects of parasites on their fish hosts maybe exacerbated by different pollutants including heavy metals and hydrocarbons, organic enrichment of sediments by domestic sewage and others such as parasite life cycles and fish population size.

Despite their potential ecological and environmental effects, parasites of exotic fish remain an underestimated
component of ecosystem functioning. Among these parasites, Digenea have the most complex life cycles that make
them difficult to be introduced. In the Gulf of Gabes (Central Mediterranean Sea), four herbivorous fish are present: two
native Sarpa salpa and Sparisoma cretense and two lessepsian Siganus rivulatus and Siganus luridus. These fishes are
assumed to have feeding analogies that increase the possibility to be infested by the same digenean species.
Comparative parasitological studies of these fishes in sympatric sites are crucial to understand parasite circulation.
Thirteen S. rivulatus, 33 S. luridus, 30 S. cretense and 20 S. salpa were studied for their digenean parasites. The two
lessepsian S. rivulatus and S. luridus have the same and only parasite Aponorus sigani. Sparisoma cretense has only one
species Schikhobalotrema sparisomae and S. salpa is parasitised with 6 species Centroderma spinosissima, Mesometra
orbicularis, Mesometra brachycoelia, Wardula capitellata, Lepocreadium pegorchis, Robphildollfusium fractum.
No parasites switching between these herbivorous fish were observed. Absence of intermediate host and phylogenetic
barrier may prevent transfer of parasite. The introduced species was considerably less parasitised than those from
native locality (10 species were reported from S. rivulatus and S. luridus of Red Sea and only one species from
Mediterranean Sea). A. sigani is a co-introduced parasite established with its host and its intermediate host in
Mediterranean Sea.

This paper contains a collection of 817 citations (no conference abstracts) on topics related to extant and extinct Chondrichthyes (sharks, rays, and chimaeras) as well as a list of Chondrichthyan species and hosted parasites newly described in 2017. The list is the result of regular queries in numerous journals, books and online publications. It provides a complete list of publication citations as well as a database report containing rearranged subsets of the list sorted by the keyword statistics, extant and extinct genera and species descriptions from the years 2000 to 2017, list of descriptions of extinct and extant species from 2017, parasitology, reproduction, distribution, diet, conservation, and taxonomy. The paper is intended to be consulted for information. In addition, we provide data information on the geographic and depth distribution of newly described species, i.e. the type specimens from the years 1990 to 2017 in a hot spot analysis. New in this year's POTY is the subheader "biodiversity" comprising a complete list of all valid chimaeriform, selachian and batoid species, as well as a list of the top 20 most researched chondrichthyan species.

Dans le cadre du Plan National de Développement Aquacole (1985‐2009), 15 espèces (Huître, Crustacé, Poissons) ont été importées et plus de 56 hydrosystèmes ont fait l'objet de multiples introductions de poissons totalisant un effectif de 36 millions d'alevins. Pour la pisciculture continentale, les importations de Hongrie (1985‐2001) ont concerné Aristichthys nobilis, Hypophthalmichthys molitrix, Ctenopharyngodon idella, Cyprinus carpio, Sander lucioperca et Silurus glanis ainsi que trois introductions accidentelles, Lepomis gibbosus, Carassius gibelio et Lampetra fluviatilis. Les Cichlidés O.niloticus x O.mossambicus et Oreochromis niloticus importés d'Egypte (2002‐2006) sont destinés à la Tilapiculture en zone semi‐aride et aride. L'huître japonaise Crassostrea gigas a été introduite dans la lagune Mellah, et plus récemment (2008‐2009), des alevins de Sparus aurata et Dicentrarchus labrax importés d'Espagne et d'Italie sont introduits dans l'Est du littoral algérien soit à des fins d'élevages intensifs en race‐ways en béton (Cap Djenet) ou en cages flottantes (Azzefoune). La crevette Penaeus monodon (Marsa‐Skikda) est en phase d'élevage préliminaire. Ces importations massives sont à l'origine d'introduction en Algérie de divers bioagresseurs incluant deux viroses (Virus de l'inflammation de la vessie gazeuse et Virus de la virémie printanière de la carpe, une bactérie pathogène Flexibacter maritimus chez D.labrax et 15 Cyprinidés et Tilapias selon la spécificité parasitaire). Les impacts environnementaux les plus importants au niveau du Parc National d'El Kala concernent l'eutrophisation du lac Oubeira et la prolifération de Cyanophycées responsables de mortalités régulières de l'ichtyofaune ainsi que l'envahissement du réseau hydrique de la wilaya de Tarf par Carassius gibelio.

Many bucephalid species, mainly of the subfamily Prosorhynchinae, have been described from epinepheline serranids (groupers) throughout the World’s Oceans. In this paper eight named prosorhynchine species are described and/or illustrated from epinepheline fishes from New Caledonia. Neidhartia lochepintade n. sp. in Epinephelus chlorostigma differs from other Neidhartia spp. in various combinations of distinct body-size, rhynchus size, previtelline and pre-mouth distance, post-testicular distance, cirrus-sac reach and egg-size. Other species are: Neidhartia haywardi Bott, Miller & Cribb, 2013 in Plectropomus leopardus; Neidhartia tyleri Bott, Miller & Cribb, 2013 in Plectropomus leopardus and Plectropomus laevis; Prosorhynchus freitasi Nagaty, 1937 in Plectropomus leopardus and Plectropomus laevis; Prosorhynchus robertsthomsoni Bott & Cribb, 2009 in Cephalopholis argus; Prosorhynchus longisaccatus Durio & Manter, 1968 in Cephalopholis urodeta, Epinephelus areolatus, Epinephelus cyanopodus and Epinephelus maculatus. Prosorhynchus luzonicus Velasquez, 1959 and Prosorhynchus sp. B. in Epinephelus coioides; Prosorhynchus serrani Durio & Manter, 1968 in Variola albimarginata and Variola louti; Prosorhynchus sp. A in Epinephelus morrhua; Prosorhynchus sp. immature in Epinephelus coeruleopunctatus. The new combination Neidhartia longivesicula (Bilqees, Khalil, Khan, Perveen & Muti-ur-Rehman, 2009) (Syn. Prosorhynchus longivesicula) is formed. Evidence from this paper and earlier molecular studies indicates that there are numerous morphologically similar prosorhynchine species in serranids, most of which show a high degree of host-specificity.

A review of various factors affecting parasite assemblages in fish hosts is presented. These factors are broadly divided into two: Biotic and abiotic factors. Biotic factors such as host age and size, host size and parasites size, host specificity, host diet and host sex and their influence on the abundance and distribution of parasites are considered and highlighted. Equally, seasonality and other environmental factors that may facilitate the establishment and proliferations of parasites in host populations are also highlighted.

Two cestodes, nine nematodes, five acanthocephalans, seven digeneans, two isopods and a copepod were recorded from approximately 200 flathead fishes, of seven species, from the north coast of New South Wales during 1977-79, from estuaries to depths of 300 m. Descriptions are given of two new species of nematodes (Raphidascaroidesfisheri, sp. nov., and Spirocamallanus platycephali, sp. nov.) one new acanthocephalan (Rhadinorhyncl~usb icircumspinis, sp. nov.), female of an unknown Raorhynchus sp., larvae of Raphidascaris  or Raphidascaroides and Echinocephalus spp.. and digeneans of Lecithochirium sp, and Cryptogonimidae. New host and/or locality records are given for female Philometra pellucida, a male Cucullanus armatus, digeneans Erilepturus platycephali, Erilepturus sp.. Aponurus laguncula, Didymozoon brevicolle, Prosorhynchus tsengi, the copepod Pterochondria alatalongicollis, isopods Nerocila laticauda, Codonophilus imbricatus, and larval species of ATybelinia, Anisakis (I), Thynnascaris (111 and IV): Serrasentis sagittijer, Gorgorhynchus celebesensis, Corynosoma clavatum and a phyllobothrid cestode. Parasites were used as biological indicators of their hosts' habitat, feeding behaviour and trophic level; ecological specificity was important for parasite infection in flathead fishes. Macrohabitat distributions of hosts, as shown by diet and locality. was also important to parasite species; parasite faunas of estuarine P, filscus and oceanic P. bassensis contrasted markedly. In P, bassensis, populations of all parasites except P. pellucida were overdispersed (clumped); host age seemed the most significant contributory factor. Some species of parasite, e.g. digeneans, were site-specific but others (most larval species) were distributed over large areas of the gut showing considerable overlap. The effects of P. pellucida upon its habitat (the gonads) were examined briefly, and some aspects of this worm's ecology were investigated.

Trematodes belonging to the Phylum Platyhelminth are poorly studied in fishes of Karachi coast and the literature is also widely
scattered. Shaukat and Bilqees prepared a check list of Trematodes in 2005. But later no such work was conducted. Therefore; it was
desired to prepare an updated checklist of Trematodes from Karachi coast. At present, a total of 198 species of trematodes are known
from the Karachi coast of Pakistan reported by various authors.

Chapter I. Material and methods
1. Material
A list of the parasites studied (and their hosts) is given: about 40 species of Monogeneans, 10 Digeneans, some Cestodes and Temnocephala.
2. Methods
The methods used for parasite collection, light and transmission electron microscopy are described.

Chapter II. Descriptive study of spermiogenesis and spermatozoa
1. Gross structure of the testis
The testis contains supporting cells, and germinal cells which are grouped in a common cytoplasmic mass at the spermatid stage. The evolution of this mass is described.
2. Spermiogenesis
A "classical" spermiogenesis is described in the Digeneans: 7 stages are defined. This spermiogenesis is also found in the Polyopisthocotylean Monogeneans. The various processes of spermiogenesis of other species may be compared with the "classical" spermiogenesis; they show modifications which are generally simplifications. A general Table showing the possible homologies between the stages of spermiogenesis found in the different species is proposed. In the case of the schistosome, after analysing the spermiogenesis, we suggest considering its aberrant spermatozoon as "neotenic", because it resembles a precociously matured spermatid. The fate and possible role of two organelles of the spermatid which are absent in the spermatozoon, the centre body and the striated roots, are considered. The process of separation of the nature spermatozoon is discussed. The aberrant case of the Polyopisthocotylean Monogenean Diplozoon is underlined, because it is the single case which cannot be compared with the "classical" spermiogenesis. The spermiogenesis of Monogeneans and Digeneans is compared with that of the other Platyhelminthes: it is close to that of Cestodes, but it shows fundamental differences from that of Turbellarians, in spite of a superficial resemblance of the spermatozoa.
3. Structure of the mature spermatozoa
Spermatozoa of Digeneans and Monogeneans are generally filiform. A Table compares the length of spermatozoa in various species. A "classical" pattern of spermatozoon (or type 1) is described: it comes from the "classical" spermiogenesis. The "classical" spermatozoon contains two axonemes incorporated in the sperm body and cortical longitudinal microtubules. This "classical" pattern is almost universal within Digeneans and Polyopisthocotylean Monogeneans, but is unknown in the Monopisthocotylean Monogeneans. It also exists, in a slightly modified form, in some Cestodes. Spermatozoa of the Monopisthocotylean Monogeneans are classified by means of two simple ultrastructural characteristics, the number of axonemes (1 or 2) and the presence of cortical microtubules, in three patterns (types 2, 3 and 4). The cases of the Digenean Schistosoma (non filiform) and of the Polyopisthocotylean Monogenean Diplozoon (aflagellate) are aberrant and set aside. Comparative diagrams are presented.
4. The organelles of the spermatozoon and their evolution during spermiogenesis
Centrioles of mature spermatozoa are atypical and are generally made up of 9 singlets, instead of the typical structure of triplets found in the spermatids. The axonemes show a special pattern, called 9+ ''1 "; the few variations are presented. The ornamentations associated with the membrane are described. The position of the nucleus is discussed: it is posterior, meaning that spermatozoa of Digeneans and Monogeneans are "inverted" compared with those of other animals. Coils of spermatozoa found in some species are considered to be details added to a fundamentally filiform structure.
5. Motility of spermatozoa
Comparative Tables of spermatozoan motility and ultrastructure (axonemes and microtubules) are given. It is impossible to correlate in a precise manner ultrastructure and motility.
6. Behaviour of the spermatozoa during fertilization
The spermatozoa penetrate the oocyte with the nucleus in a posterior position; available data concern only few species, mainly with "classical" spermatozoa.
7. Partial conclusion after chapter II
Data advanced in this chapter are summarised and discussed.

Chapter III. Morphology of spermatozoa, biology of fertilization and phylogeny
1. Introduction
Some classical cases of the literature are considered.
2. Spermatozoa and biology of fertilization
The "classical" spermatozoon (type 1 ) of the Digeneans and Polyopisthocotylean Monogeneans seems to be linked with internal fertilization, through genital ducts (Digeneans) or by hypodermic injection (at least a part of the Polyopisthocotylean Monogeneans). In the monopisthocotylean Monogeneans (with spermatozoa of types 2, 3 and 4), the literature mentions some cases of spermatophores, but it is not possible to establish a strict relationship between these sperm structures and fertilization by spermatophore. The case of the Polyopisthocotylean Monogenean Diplozoon is interesting. In this animal, the biology of fertilization is unique because the two members of the pair are fused, and the spermatozoon is the only aflagellate case known: it displays a remarkable correlation between the biology of fertilization and sperm structure. The case of the schistosomes is discussed. Attempts are made to relate the atypical structure of the spermatozoon to the peculiar characteristics of the schistosomes: gonochorism, progenesis, life in pairs. It seems that life in permanent pairs is a factor of differentiation of atypical sperm structures, in the schistosomes, Diplozoon, and some Didymozoonidae.
3. Spermatozoa and phylogeny
Relationships between phylogeny, taxonomy, biology of fertilization and sperm structure are discussed. In the Trematodes (Digeneans and Aspidogastreans), the sperm structure is very homogenous (type 1) and thus of little use for the understanding of phylogeny within this group. The few variations known (Didymozoata and Strigeata) seem to be linked mainly with the biology of fertilization rather than with phylogeny. In the Monogeneans, comparative spermatology allows us to separate Polyopisthocotyleans and Monopisthocotyleans. Polyopisthocotylean Monogeneans are very homogenous and share type 1 with the Trematodes. The single really different case, Diplozoon, seems to have no phyletic value but is correlated with the biology of fertilization. Monopisthocotylean Monogeneans show three types of spermatozoa. A phyletic scheme built only from sperm ultrastructure shows resemblances with classical phylogenies drawn from the structure of the adults, and a remarkable coincidence with modern phylogenies elaborated from the structure of larvae. The case of the Monogeneans is thus a demonstrative example of the usefulness of comparative spermatology for the understanding of phylogeny.
4. Trends in the evolution of spermatozoa in parasitic Platyhelminthes
Spermatozoa of Platyhelminthes are generally biflagellate. After a comparative study, we consider that the less evolved spermatozoon in the parasitic Platyhelminthes (Monogeneans, Digeneans and Cestodes) is the "classical" type, or type 1. This type 1 is maintained in the Digeneans and Polyopisthocotylean Monogeneans, but is modified in the Cestodes (loss of the mitochondrion, and of one axoneme in some cases), and in the Monopisthocotylean Monogeneans (loss of the microtubules am of one axoneme). The origin of type 1 may possibly be found in the Turbellaria Rhabdocoela Kalyptorhynchia. Comparative and phyletic diagrams of sperm structure in the phylum Platyhelminthes are given.

The knowledge of the biodiversity of parasitic copepods in South Korea is increasing. Interestingly we report here, some parasitic copepods considered as the first record of findings from Korea. Nine species of parasitic copepods (Siphonostomatoida) including six genera of three different families [Caligidae (7), Lernaeopodidae (1), Lernanthropidae (1)] were recovered from eight species of wild fishes in Korea:

This is the second version of the database report “Host-Parasite List” and “Parasite-Host List” of cartilaginous fishes (Chondrichthyes: Elasmobranchii, Holocephali). The two lists result from the analysis of 1,078 research articles reporting on host-parasite relations in diverse species of sharks, rays, and chimaeras. The list contains 6,891 records in total. This edition contains 2,036 different species of parasites recovered from 495 species of elasmobranchs. All information about the parasites are also available at http://shark-references.com/species/host-parasites-list/A or http://shark-references.com/species/parasite-hosts-list/A  (weekly update).

This text speculates on the limits of kinship towards non-human otherness via the figure of a toxic fish that migrated from the Red Sea into Mediterranean waters over the last decade. In post-anthropocentric approaches to otherness, the boundary between the human and the animal is presumably blurred, it becomes immeasurable, discontinuous or 'abyssal' – to use Derrida's phrasing – rather than a single dividing line. Conversely, the representations and treatment of this toxic fish by fishing communities consolidates, rhetorically and materially, a strong dividing line between us and them, the human and the non-human other. The constitutive fragility of this dividing line and its ongoing contestations, it will be argued, harbours the tensions inhabiting post-humanist politics and ethics, involving questions of class, anthropocentric bias, the possibilities of interspecies communication, and attempts to rearrange species-based hierarchies.

Parasitological investigation carried out on freshwater fishes from lake Oubeira showed several entities: Bothriocephalus acheilognathi (Cestoda: Pseudophyllidea), Khawia armeniaca (Cestoda: Caryophyllidea), Acanthogyrus (Acanthosentis) maroccanus (Acanthocephala; Quadrigyridae) in Barbus callensis Cuv. & Val., 1842 (Cyprinidae) and Neoechinorhynchus agilis (Acanthocephala; Neoechinorhynchidae) in Grey mullets Mugil cephalus and Liza ramada. Light and Scanning Electron Microscope study enabled the description of morphological details to be used for specific diagnosis of these parasites.

Parasite biodiversity of fish of the southern part of the Mediterranean sea is still incompletely explored. We describe here Microcotyle visa n. sp. from the gill filaments of the bluespotted seabream Pagrus caeruleostictus (Valenciennes) (Sparidae) collected off the Algerian coast. The identity of fish hosts was confirmed by barcoding. Microcotyle visa n. sp. is herein described and illustrated. Analysis of the cox1 gene of the monogeneans revealed minor intraspecific variation (1.4{\%}), an order of magnitude lower than the distance between this species and other Microcotyle species (10--15 {\%}). Microcotyle visa n. sp. is distinguished from Microcotyle erythrini van Beneden {\&} Hesse, 1863, a congener infesting sparids, on the basis of morphological (size of clamps, number of testes) and molecular (cox1) differences. This is the fourth member of the genus known to parasitise a sparid host. A species of Paramicrocotyle sp. included in the molecular analysis was nested within a robust Microcotyle + Paramicrocotyle clade; in the absence of demonstrated molecular and morphological differences, we consider that Paramicrocotyle Caballero {\&} Bravo-Hollis, 1972 is a junior synonym of Microcotyle van Beneden {\&} Hesse, 1863 and transfer two species of Paramicrocotyle as Microcotyle danielcarrioni (Martinez {\&} Barrantes, 1977) n. comb. and Microcotyle moyanoi (Villalba {\&} Fernandes, 1986) n. comb.

AbstractAimPublished information on the richness and diversity of helminth parasite communities in tropical freshwater fishes is reviewed in response to expectations of species-rich parasite communities in tropical regions.Published information on the richness and diversity of helminth parasite communities in tropical freshwater fishes is reviewed in response to expectations of species-rich parasite communities in tropical regions.LocationAreas covered include the tropics and some subtropical areas. In addition, the north temperate area of the nearctic zone is included for comparison.Areas covered include the tropics and some subtropical areas. In addition, the north temperate area of the nearctic zone is included for comparison.MethodsData from 159 communities in 118 species of tropical freshwater fish, summarized from 46 published studies, were used for this review. Parasite community descriptors used in the analyses included component community richness and calculated mean species richness. Data from 130 communities in 47 species of nearctic north temperate freshwater fish were summarized from 31 studies and used for comparison.Data from 159 communities in 118 species of tropical freshwater fish, summarized from 46 published studies, were used for this review. Parasite community descriptors used in the analyses included component community richness and calculated mean species richness. Data from 130 communities in 47 species of nearctic north temperate freshwater fish were summarized from 31 studies and used for comparison.ResultsThe component helminth communities of many tropical freshwater fish are species-poor, and considerable proportions of fish from certain parts of the tropics, e.g. West African drainages, are uninfected or lightly infected. Mean helminth species richness was low and equaled or exceeded 2.0 in only 22 of 114 communities. No single group of helminths was identified as a dominant component of the fauna and species composition was variable among and within broader geographical areas. The richest enteric helminth assemblages were found in mochokid and clariid catfish with a mixed carnivorous diet, whereas algal feeders, herbivores and detritivores generally had species-poor gut helminth communities. Comparisons indicated that certain areas in the north temperate region had higher helminth species richness in fishes than areas in the tropics.The component helminth communities of many tropical freshwater fish are species-poor, and considerable proportions of fish from certain parts of the tropics, e.g. West African drainages, are uninfected or lightly infected. Mean helminth species richness was low and equaled or exceeded 2.0 in only 22 of 114 communities. No single group of helminths was identified as a dominant component of the fauna and species composition was variable among and within broader geographical areas. The richest enteric helminth assemblages were found in mochokid and clariid catfish with a mixed carnivorous diet, whereas algal feeders, herbivores and detritivores generally had species-poor gut helminth communities. Comparisons indicated that certain areas in the north temperate region had higher helminth species richness in fishes than areas in the tropics.Main conclusionsExpectations of high species richness in helminth communities of tropical freshwater fishes are not fulfilled by the data. Direct comparisons of infracommunities and component communities in host species across widely separated phylogenetic and geographical lines are inappropriate. Examination of latitudinal differences in richness of monophyletic parasite groups or of compound communities may uncover patterns different from those found in this study. Richness of helminth communities may be ultimately determined not by the number of host species present but by the degree of divergence of host lineages and by their diversification modes. A phylogenetic framework for hosts and parasites will reveal if increased host species richness within host clades, when host speciation is accompanied by habitat or diet specialization, or both, leads to lower helminth diversity in host species by fragmentation of a core helminth fauna characteristic or specific of the larger host clade. This pattern may be analysed in the context of cospeciation and acquisition from other unrelated hosts (host-sharing or host-switching).Expectations of high species richness in helminth communities of tropical freshwater fishes are not fulfilled by the data. Direct comparisons of infracommunities and component communities in host species across widely separated phylogenetic and geographical lines are inappropriate. Examination of latitudinal differences in richness of monophyletic parasite groups or of compound communities may uncover patterns different from those found in this study. Richness of helminth communities may be ultimately determined not by the number of host species present but by the degree of divergence of host lineages and by their diversification modes. A phylogenetic framework for hosts and parasites will reveal if increased host species richness within host clades, when host speciation is accompanied by habitat or diet specialization, or both, leads to lower helminth diversity in host species by fragmentation of a core helminth fauna characteristic or specific of the larger host clade. This pattern may be analysed in the context of cospeciation and acquisition from other unrelated hosts (host-sharing or host-switching).

Marine fish species such as grey wrasse Symphodus cinereus, common sole Solea solea, knout goby Mesogobius batrachocephalus and rusty blenny Parablennius sanguinolentus were studied for their parasitic isopods on the Sinop coast of the Black Sea. Two cymothoid species (Nerocila bivittata and Nerocila orbignyi) were identified. Nerocila bivittata was found on the body surface and fins of grey wrasse, common sole, knout goby, and N. orbignyi on the dorsal fin of rusty blenny. The prevalence and mean intensity values of each parasite species on fishes were calculated. Fish species mentioned above were all new hosts for N. bivittata and N. orbignyi in the Turkish coast of the Black sea.