Metazoan parasites of Sebastes capensis from two localities in northern Chile as tools for stock identification

Examination of 290 red rockfish Sebastes capensis from two fishing grounds in northern Chile (Coquimbo 71°30' W; 30°0' S and Antofagasta 70°40' W; 23°30' S) revealed 8770 metazoan parasites, belonging to 18 taxa: Udonella caligorum (Udonellidae); Interniloculus chilensis , Paramicrocotyle sp. and Neobenedenia melleni (Monogenea); larval Gnathia sp., Cirolana sp. and Rocinela sp. (Isopoda); Helicometrina nimia , Diphtherostomum sp., Lecithochirium sp. and Pseudopecoelus sp. (Digenea); Ascarophis sebastodis , Anisakis sp. and larval Hysterothylacium sp. (Nematoda); Caligus cheilodactylus , Lepeophtheirus chilensis and Trifur tortuosus (Copepoda); larval Corynosoma australe (Acanthocephala). Ten species were found only in Coquimbo and three were found only in Antofagasta, species common to both localities were Pseudopecoelus sp., C. australe , Anisakis sp. and A. sebastodis . Evidence, based on qualitative differences between the parasite faunas of the red rockfish, suggests the existence of two discrete stocks.     

Metazoan parasite fauna as a biological tag for the habitat of the flounder Hippoglossina macrops from northern Chile, in a depth gradient

Quantitative changes in the parasite communities of the flounder Hippoglossina macrops (Steindachner) were studied along a depth gradient. Samples were obtained from the waters off Coquimbo, Chile (29 degrees 18'S to 30 degrees 50'S), at depths ranging from 160 to 342 m. Samples were assigned to 3 depths, i.e., shallow water (less than 200 m), midwater (from 200 to 300 m), and deep water (more than 300 m). Twelve parasite species were recorded: Neoheterobothrium chilensis and Entobdella hippoglossi (Monogenea); Holobomolochus chilensis and Protochondria longicauda (Copepoda); Gliptonobdella sp. (Hirudinea); Nybelinia surmenicola, Scolex pleuronectis, and Neobothriocephalus adspinosus (Cestoda); Floridosentis sp. and Corynosoma australe (Acanthocephala); Anisakidae (Nematoda); and an unidentified hemiurid (Digenea). Univariate analyses showed that C. australe has its highest prevalence and mean intensity of infection in hosts from shallow waters. Floridosentis sp. showed significant differences along the depth gradient, with higher mean intensity and prevalence of infection in fish from midwater. Among the ectoparasites, only N. chilensis exhibited differences in mean intensity with depth, where intensity of infection increased with depth of host habitat. A canonical multivariate analysis demonstrated that parasite burdens can be a good predictor of the environment (shallow, mid-, or deep water) occupied by the flounders.     

Nerocila benrosei n. sp. (Isopoda: Cymothoidae), an external parasite of hogfishes from the northern Bahamas

Nerocila benrosei n. sp. is described from the hogfish, Lachnolaimus maximus (Walbaum), and the Spanish hogfish, Bodianus rufus (Linnaeus), (Perciformes: Labridae) from the northern Bahamas. Nerocila benrosei differs from all species of Nerocila by having the body of females 1.4-1.9 times as wide as long, instead of 2.0-3.0 times, and pleopods 1 and 2 lacking accessory lamellae. It differs from the only species of Nerocila with which it overlaps geographically, N. lanceolata (Say, 1818), by having the lateral margins of pleonites 1-5 strongly produced ventrally, coxae 5-7 manifestly shorter than the posterolateral projection of the respective pereonite, and a vaulted dorsal surface. The species of Nerocila in the northwestern Atlantic have almost mutually exclusive geographic ranges: New England to Panama, including Bermuda and the northern coast of Cuba (Nerocila lanceolata); Brazil to Trinidad and Tobago (Nerocila fluviatilis Schi?dte and Meinert, 1881); and the northern Bahamas and Bermuda (Nerocila benrosei). No species of Nerocila have been reported from the insular Caribbean. Nerocila benrosei appears to be highly host and site specific.     

Spatial variation in parasite abundance: evidence of geographical population structuring in southern garfish Hyporhamphus melanochir

Southern garfish Hyporhamphus melanochir were examined for metazoan parasites from nine sites in three regions (Spencer Gulf, Gulf St Vincent and northern Kangaroo Island) in South Australia to document parasite assemblages, identify candidate species suitable for use as biological tags and investigate spatial variation in parasite abundance. Four ectoparasite and 10 endoparasite species were identified representing Cestoda, Trematoda, Monogenea, Nematoda, Acanthocephala, Copepoda and Isopoda. Lernaeenicus hemirhamphi, Micracanthorhynchina hemirhamphi, Mothocya halei and Philometra sp. were suggested for 'permanent' biological markers. Multivariate discriminant function analysis showed that most sites could be distinguished based on differences in parasite abundance. Four endoparasites (Conohelmins sp., Hysterothylacium sp., M. hemirhamphi and Philometra sp.) were most important for site characterization. Limited spatial variation in permanent endoparasite abundance among localities in northern Spencer Gulf provided evidence for a distinct northern Spencer Gulf population with little interregional mixing. In contrast, considerable spatial variation in permanent endoparasite abundance between localities sampled off Kangaroo Island implied limited local movement and suggested H. melanochir may comprise a metapopulation structure. These results largely align with recent evidence from otolith chemistry that indicates fine-scale geographical population structuring in South Australian waters.     

Metazoan parasites as biological indicators of population structure of Halobatrachus didactylus on the Portuguese coast

A total of 366 Halobatrachus didactylus (Bloch & Schneider 1801) individuals were obtained between September and November 2000 from commercial fishing vessels at eight localities along the Portuguese coast and analysed for metazoan parasite infections. Three species of parasites were found: Hysterothylacium aduncum Rudolphi 1802; Progrillotia dasyatidis Beveridge et al. 2004, which constitutes a new host record for the Lusitanian toadfish; and Nerocila orbignyi Guérin‐Méneville 1829. Prevalence and mean abundance were determined for the total fish population in each sample. Significant differences in the number of parasitized fish among the samples analysed indicate differences in the H. didactylus populations along the Portuguese coast. The cluster analysis performed to prevalence data pointed out two major clusters: one composed of mainly estuarine samples and one that grouped samples from coastal areas; this is in agreement with the results obtained by morphological and genetic analysis performed for the same samples.     

Parasitological diversity of the common goby, Pomatoschistus microps (Krøyer, 1838), in estuarine systems along the Portuguese coast

Parasitological diversity of the common goby Pomatoschistus microps along the Portuguese coast was studied based on samples collected using beam trawls in five coastal estuaries (Ria de Aveiro, Tagus, Sado, Mira and Guadiana estuaries) between May and July 2006. The classes Digenea, Cestoda, Nematoda and phylum Mastigophora were found, with Digenea Cryptocotyle sp. and Lecithochirium musculus being the most abundant taxa. Prevalence and mean abundance of Cryptocotyle sp. were highest in Ria de Aveiro (74%) and Mira estuary (28.05), respectively, whereas L. musculus values of both indices were highest in Sado estuary (prevalence = 64%; mean abundance = 11.77). Values varied along the Portuguese coast; the discriminant analysis based on the number of parasites showed some overlap between estuaries, although successfully separating the Sado and Mira estuaries. Overall, variations in estuaries were explained by different environmental pressures, leading to differences on host abundance and life-history of the parasites. Feeding behaviour and habitat selection therefore play a crucial role in shaping the biology, ecology and parasite assemblages of the common goby along the Portuguese coast.     

Site selection of Acanthochondria cornuta (Copepoda: Chondracanthidae) in Platichthys flesus (Teleostei: Pleuronectidae)

Acanthochondria cornuta (Copepoda: Chondracanthidae) (N=4841; prevalence: 80·0%; mean±s.d. [range] intensity: 28·8±24·0 [1-110] parasites) infected the branchial chambers of the European flounder, Platichthys flesus (L.), (N=210) according to an established spatial pattern. This was independent of host size. Higher intensities resulted, most frequently, in higher numbers of infection sites, probably due to increased intraspecific competition. Preferential infection of the ocular side was supported by the recorded abundance data and reflected, probably, the fish's bottom-dwelling behaviour. As the parasite develops from one stage into another, it seems to migrate towards different sites: the copepodites and pre-adult females occurred, mainly, in the holobranchs; the adults preferred the internal wall (non-gravid/post-gravid females; adult males) or the pseudobranchs (gravid females). The ventilating water current along with the blood supply are suggested as 2 major factors in determining parasite spatial distribution within the chamber. Parasite crowding in a restricted and narrow space of the posterior region of the internal wall was recorded frequently and resembled that previously reported for the plaice. Differences to other host-parasite systems previously studied should relate with the anatomy of the respiratory apparatus. Bigamous females are reported for the first time.     

REGULAR PAPERS Unusual stable isotope fractionation patterns observed for fish host—parasite trophic relationships

Trophic relationships between four taxa of fish parasite (Cestoda, Nematoda, Isopoda, Copepoda) and their hosts ( Gasterosteus aculeatus, Merlangius merlangus, Boops boops, Platichthys flesus ) were investigated using stable isotopes of carbon and nitrogen. δ¹⁵N differences between parasite and host were unlike those conventionally observed among consumers and their diets. In no case were parasites enriched in 15N with respect to the host organism; endoparasites were significantly and consistently depleted. In no case were parasites enriched in 15N with respect to the host organism; endoparasites were significantly and consistently depleted.     

The parasite community infecting flounders, Platichthys flesus, in the tidal Thames.

The composition of the parasite fauna of the flounder, Platichthys flesus, retrieved from two locations in the tidal Thames is described in detail for the first time. The combined parasite species list of the flounders from Lots Road in the upper tideway and West Thurrock in the middle tideway consisted of one protozoan (Glugea stephani), one monogenean (Gyrodactylus sp.), four larval digeneans (Cryptocotyle concava, Timoniella imbutiforme, T. praeterita, and Labratrema minimus), five adult digeneans (Derogenes varicus, Lecithaster gibbosus, Podocotyle sp., Plagioporus varius, and Zoogonoides viviparus), one larval cestode (unidentified tetraphyllidean), one or possibly more larval nematodes (unidentified) plus five adult nematodes (Capillaria sp., Cucullanus heterochrous, C. minutus, Contracaecum sp. and Goezia sp.), two acanthocephalans (Pomphorhynchus laevis and Acanthocephalus anguillae), three copepods (Lepeophtheirus pectoralis, Acanthochondria sp. and Lernaeocera branchialis), and one mollusc (unidentified glochidia). The overall parasite community of flounders from Lots Road and West Thurrock were compared in terms of species richness and diversity. The parasite community in flounders from the former location in the upper tideway was found to be less diverse than that of its counterpart at West Thurrock in the middle estuary. The component community of Lots Road flounders was dominated by the acanthocephalan Pomphorhynchus laevis.     

Parasite communities of the spotted rose snapper Lutjanus guttatus (Perciformes: Lutjanidae) off the Mexican Pacific coasts: Spatial and long-term inter-annual variations

A total of 802 individuals of Lutjanus guttatus (Steindachner, 1869) specimens were collected over a 10-year period (August 2012 to February 2021) from four locations on the south-central Pacific coast of Mexico. Their parasite communities were quantified and analyzed to determine if they experience significant spatial and inter-annual variations.Thirty-two taxa of metazoan parasite were recovered and identified: four species of Digenea, four Monogenea, one Cestoda, two Acanthocephala, seven Nematoda, one Hirudinea, and nine of Crustacea (six Copepoda, and three Isopoda). Species richness was greatest among the digenean group, which represented 25% of the total species recovered, followed by the nematodes (22% of total species). Species richness at the component community level (10 to 20 species) was similar to reported richness in other Lutjanus spp. The component communities and infracommunities exhibited a similar pattern: low species richness and diversity, and dominance by a single species, mainly the monogenean Haliotrematoides guttati. Parasite community structure and species composition varied through the years, as well as between sampling locations. Variations were possibly caused by a combination of biotic and abiotic factors which generated notable changes in the infection levels of several component species. However, the similarity in the parasite species composition was high locally for short-term periods (one or two years). This result, therefore, suggests that parasite communities of L. guttatus may be more predictable locally, but only for short-term periods.     

<Emphasis Type="Italic">Caligus ignotus</Emphasis> n. sp. (Copepoda: Caligidae) parasitic on Poey’s scabbardfish <Emphasis Type="Italic">Evoxymetopon poeyi</Emphasis> (Günther) off Taiwan

A new species of caligid copepod, Caligus ignotus n. sp., is described from Poey’s scabbardfish Evoxymetopon poeyi (Günther) (Trichiuridae) caught off the southeast coast of Taiwan. The parasite was found in the gill-cavity of this benthopelagic fish. The new species is distinguished from its congeners mainly in the structure of the female genital complex (shaped like a guitar) and abdomen (with three sections and gradually broadening from anterior to posterior). This is the first report of a copepod parasite from Poey’s scabbardfish.     

Parasites and size-assortative schooling in three-spined sticklebacks

Recent field studies carried out in lacustrine environments have suggested that fish schools may be assorted with respect to parasite infections, but the generality and strength of parasite-assortative schooling in fish is unclear. In this study, data are presented on the body size and externally visible macroparasite load of 366 individual three-spined sticklebacks Gasterosteus aculeatus L. (Gasterosteidae, Teleostei) from six naturally formed schools captured in the Gullmarsfjord on the west coast of Sweden. Length–frequency analysis suggested that two separate year classes (presumed 0+ and 1+) were represented in the sample. Individual schools were assorted by body size, and contained largely fish of a single year class. The number of fish in the school was negatively related to median body size of members. Probability of infection increased significantly with fish length for two parasites ( Cryptocotyle lingua (Trematoda) and Glugea anomala (Microsporidia)), and marginally for a third (chalimus larvae of Caligus sp. (Copepoda)). After correcting for body-size effects, the proportion of school members infected with C. lingua and G. anomala did not differ significantly from a model of random assortment by infection status. However, two of the six schools were found to have significantly more, or significantly fewer, members infected with Caligus sp. chalimus larvae than predicted by the random model. Significant inter-school differences in the intensity of C. lingua infection were also detected, but these resulted from the combined effects of size-assortment and a strong correlation between body size and infection intensity. The results of this study provide only limited support for the existence of active parasite-assortative schooling in marine sticklebacks, and are discussed in relation to recent studies of parasite assortment amongst host fish in other ecosystems.     

Free-living marine Rhabdocoela (Platyhelminthes) from the N. American Pacific coast. With remarks on species from other areas

From the N. American Pacific coast the following taxa are described: Coronopharynx pusillus Luther, Pogaina bicornk sp.n., P. paranygulgus sp.n. (Provorticidae); Brinkmanniella palmata sp.n., Tvaerminnea karlingi pucifica subsp.n. (Promesostomidae); Trigonostomum setigerum O. Schmidt, Messoplana pacifica sp.n., Ceratopera axi (Riedl), C. ehlersi sp.n., C. pilifera sp.n. (Trigonostomidae); Polycystis ali Schockaert, P. hamata sp.n. (Polycystididae). From other areas: Brinkmanniella palmata from the Skagerrak, Black Sea and Mediterranean Sea; Ceratopera axi from the Falkland Islands; Polycystis ali from Galapagos Islands; Ceratopera bermudensis sp.n. from Bermuda. Polycystis ali is considered to be a polytypic species with the forms 'Somali', 'California' and 'Galapagos'. Brinkmanniella augusti Marcus and B. falklandica Westblad are considered to be species incertae sedis. Problems in penetrating the world-wide marine turbellarian fauna are discussed.     

The metazoan parasites of Stellifer minor (Tschudi, 1844): an ecological approach

A quantitative and qualitative analysis of the parasite fauna of the sciaenid Stellifer minor (Tschudi) from Chorrillos, Perú, was made. Some characteristics of the infectious processes, in terms of intensity and prevalence of infection, as a function of host sex and size, are given. Moreover, comments on the characteristics of the parasite fauna, related with host role in the marine food webs are included. The parasite fauna of Stellifer minor taken off Chorrillos, Perú, include the monogeneans Pedocotyle annakohni, Pedocotyle bravoi, Rhamnocercus sp. and Cynoscionicola sp., the digenean Helicometra fasciata, the adult acantocephalan Rhadinorhynchus sp. and the larval Corynosoma sp., the nematode Procamallanus sp., the copepods Caligus quadratus, Clavellotis dilatata and Bomolochus peruensis and one unidentified isopod of the family Cymothoidae. A distinctive characteristic of the parasite fauna (Metazoa) of S. minor is the almost absence of larval forms.     

Morphological and molecular characterization of Udonella brasiliensis n. sp. (Monogenoidea), an epibiont on Caligus sp. parasite of Ariidae from the southeastern coast of Brazil

The present study describes Udonella brasiliensis n. sp., an epibiont found on Caligus sp., a parasite the ariids Genidens barbus (Lacepède) and Aspistor luniscutis (Valenciennes), caught on the coast of the state of São Paulo, Brazil. Morphological and molecular analyses (partial 18S rDNA) were carried out. The morphological data showed that U. brasiliensis n. sp. can be distinguished from current valid species by its morphometric attributes (e.g., body, pharynx, ovary and testis), while the molecular information supports the proposal of a new species. The 18S rDNA phylogenetic analysis shows a close relationship between the new species and Udonella australis Carvajal & Sepulveda, in a subclade formed of species that parasitize South American fish. Finally, this study also discusses a scenario of initial irradiation for udonellids.     

Metazoan parasites of Macruronus magellanicus from southern Chile as biological tags

Examination of 450 specimens of Macruronus magellanicus from two fishing grounds in southern Chile (Talcahuano: 36°40'S, Punta Arenas: 54° S) revealed 24 205 metazoan parasites, belonging to 15 taxa with low specificity: Chondracanthus australis and Neobrachiella sp. (Copepoda); Elytrophalloides oatesi, Gonocerca phycidis, Derogenes varicus and Brachyphallus parvus , (Digenea); Hepatoxylon trichiuri, Scolex pleuronectis, Clestobothrium crassiceps, Grillotia dollfusi , Pseudophyllidea gen. sp. (Cestoda); Anisakidae, Cucullanus sp. (Nematoda), Corynosoma australe and Acanthocephala gen. sp. (Acanthocephala). The list includes parasites that are common to other merluccids from the zone. The parasitological evidence does not suggest the existence of two discrete stocks, but the existence of a migratory process from south to north.