23 research outputs found

    Comparación de los niveles de infección de anisákidos entre dos especies de caballa del Atlántico (Scomber colias y S. scombrus), de la costa atlántica portuguesa

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    Anisakiasis is a problematic zoonotic infection associated with the consumption of raw or undercooked fish. Atlantic mackerel (Scomber colias) is of high commercial interest in Portugal and has been reported as a common host of Anisakisspp. In this study, the occurrence of anisakids is evaluated in S. colias and also Scomber scombrus, and the potential zoonotic risk associated with consumption of these two fishes is evaluated according to the recorded infection levels. These were found to be high for both fish species: a mean intensity and prevalence of 21.7 worms/fish and 85% for S. colias, and 16.4 worms/fish and 83.3% for S. scombrus, respectively. No correlation was detected between anisakid intensity and host total length, total weight, condition factor, and hepatosomatic and gonadosomatic indices for both fish species, but significantly higher intensity values were detected for more mature S. scombrus, i.e. fish recording a higher gonadosomatic index. Molecular tools allowed the identification of two species of Anisakis, A. simplex (s.s.) and A. pegreffii. They differed in their occurrence: in S. colias the prevalence of A. simplex (s.s.) was 18% and that of A. pegreffii was 82%, whereas in S. scombrus the prevalence of A. simplex (s.s.) was 73% and that of A. pegreffii was 27%. Occasionally, worms of Hysterothylacium aduncum were identified for both fish. The different infection levels of the two Anisakisspecies in both hosts off the Portuguese coast raise the hypothesis of a different life cycle at the level of the invertebrate intermediate host. S. colias lives in deeper waters than S. scombrus, and the differences found in infection levels suggest that A. pegreffii main first intermediate host also live in deeper waters, compared with A. simplex (s.s.) main first intermediate host. The higher infection levels of A. simplex (s.s.) (most infectious to humans) in S. scombrus suggest that its consumption when slightly cooked, as in grilled fish (so popular in Portugal), could be more problematic for the development of anisakiasis in humans than the consumption of S. colias and thus be of potential public health concern.La anisakiasis es una zoonosis problemática asociada con el consumo de pescado crudo o poco cocinado. La caballa del Atlántico (Scomber colias) es un pez de mayor interés comercial en Portugal y se ha informado que es un hospedador común de Anisakis spp. En este estudio, la incidencia de anisákidos se evalúa en S. colias y Scomber scombrus, y el potencial riesgo zoonótico asociado con el consumo de estos dos peces se evalúa de acuerdo a los niveles de infección registrados. Estos se encontraron altos para ambas especies de peces - intensidad media y la prevalencia de 21.7 gusanos/pescado y 85% para S. colias, y 16.4 gusanos/pescado y 83.3% para S. scombrus, respectivamente. No se detectó ninguna correlación entre la intensidad de anisákidos y datos del hospedador, longitud total, peso total, factor de condición, y los índices hepatosomáticos y gonadosomáticos para ambas especies de peces, pero sí se detectaron valores de intensidad significativamente más altos para los pescados más maduros en S. scombrus, es decir, de pescado con mayor índice gonadosomático. Las herramientas moleculares permitieron la identificación de dos especies de Anisakis simplex, es decir, A. simplex (s.s.) y A. pegreffii. Ambos diferían en su ocurrencia – la prevalencia de A. simplex (s.s.) fue del 18% y del 82% A. pegreffii en S. colias, mientras que la prevalencia de A. simplex (ss) fue del 73% y del 27% A. pegreffii en S. scombrus. De vez en cuando, se identificaron los gusanos de Hysterothylacium aduncum para los dos peces. Los diferentes niveles de infección de las dos especies de Anisakis en ambos hospedadores, frente a la costa portuguesa, plantean la hipótesis de un ciclo de vida diferente en el nivel del huésped intermediario invertebrado. S. colias vive en aguas profundas frente a S. scombrus, que podría ser también cierto para primer hospedador intermediario principal de A. pegreffii en comparación com lo de A. simplex (s.s.). Los mayores niveles de infección de A. simplex (s.s.) (más infecciosos para los humanos) en S. scombrus sugieren que su consumo ligeramente cocinados, como en el pescado a la parrilla (tan popular en Portugal), podría ser más problemático en relación con el desarrollo de la anisakiasis en los seres humanos, en comparación con el consumo de S. colias y por lo tanto ser de posible preocupación de salud pública

    Invasive Ponto-Caspian Amphipods and Fish Increase the Distribution Range of the Acanthocephalan Pomphorhynchus tereticollis in the River Rhine

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    Non-indigenous species that become invasive are one of the main drivers of biodiversity loss worldwide. In various freshwater systems in Europe, populations of native amphipods and fish are progressively displaced by highly adaptive non-indigenous species that can perform explosive range extensions. A total of 40 Ponto-Caspian round gobies Neogobius melanostomus from the Rhine River near Düsseldorf, North Rhine-Westphalia, Germany, were examined for metazoan parasites and feeding ecology. Three metazoan parasite species were found: two Nematoda and one Acanthocephala. The two Nematoda, Raphidascaris acus and Paracuaria adunca, had a low prevalence of 2.5%. The Acanthocephala, Pomphorhynchus tereticollis, was the predominant parasite species, reaching a level of 90.0% prevalence in the larval stage, correlated with fish size. In addition, four invasive amphipod species, Corophium curvispinum (435 specimens), Dikerogammarus villosus (5,454), Echinogammarus trichiatus (2,695) and Orchestia cavimana (1,448) were trapped at the sampling site. Only D. villosus was infected with P. tereticollis at a prevalence of 0.04%. The invasive goby N. melanostomus mainly preys on these non-indigenous amphipods, and may have replaced native amphipods in the transmission of P. tereticollis into the vertebrate paratenic host. This study gives insight into a potential parasite-host system that consists mainly of invasive species, such as the Ponto-Caspian fish and amphipods in the Rhine. We discuss prospective distribution and migration pathways of non-indigenous vertebrate (round goby) and invertebrates (amphipods) under special consideration of parasite dispersal

    Parasites of cultured and wild brown-marbled grouper Epinephelus fuscoguttatus (Forsskal, 1775) in Lampung Bay, Indonesia.

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    A total of 210 Epinephelus fuscoguttatus (brown-marbled grouper) was examined for parasites. During three consecutive seasons (two rainy and one dry season from 2002 to 2004), 35 specimens each taken from floating net cages of the National Sea Farming Development Centre (Balai Budidaya Laut) and from wild catches in Lampung Bay, South Sumatra, Indonesia were studied. Twenty-five (cultured grouper) and 30 (wild grouper) parasite species/taxa were identified, with an infracommunity ranging from one to nine (cultured) and three to 14 parasite species (wild), demonstrating a species-rich parasite fauna even in the cultured fish. Protozoans (1 species), microsporeans (1), myxozoans (1), digeneans (8), monogeneans (5), cestodes (3), nematodes (8), acanthocephalans (2) and crustaceans (6) were found. The most abundant parasites were the monogeneans Pseudorhabdosynochus epinepheli and Pseudorhabdosynochus lantauensis for both, cultured and wild grouper during all seasons. For the cultured fish, the prevalence of monoxenous ectoparasites (e.g. P. epinepheli, P. lantauensis, Capsalidae gen. et sp. indet., Benedenia epinepheli) was in most cases higher than that of heteroxenous endoparasites. This contrasts the wild grouper, where heteroxenous parasites such as Allopodocotyle epinepheli and Raphidascaris sp. occurred at a similar prevalence compared with the fairly abundant Pseudorhabdosynochus spp. No seasonality of infestation was observed for both cultured and wild fish. The high levels of infestation of potentially pathogenic monogeneans throughout the year could result in significant parasite outbreaks at the locality studied

    Parasite diversity as an indicator of environmental change? An example from tropical grouper (Epinephelus fuscoguttatus) mariculture in Indonesia

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    Fish parasites are used to monitor long-term change in finfish grouper mariculture in Indonesia. A total of 210 Epinephelus fuscoguttatus were sampled in six consecutive years between 2003/04 and 2008/09 and examined for parasites. The fish were obtained from floating net cages of a commercially run mariculture facility that opened in 2001. The fauna was species rich, consisting of ten ecto- and 18 endoparasite species. The ectoparasite diversity and composition was relatively stable, with the monogeneans Pseudorhabdosynochus spp. (83–100% prevalence, Berger-Parker Index of 0·82–0·97) being the predominant taxon. Tetraphyllidean larvae Scolex pleuronectis and the nematodes Terranova sp. and Raphidascaris sp. 1 were highly abundant in 2003/04–2005/06 (max. prevalence S. pleuronectis 40%, Terranova sp. 57%, Raphidascaris sp. 1 100%), and drastically reduced until 2008/09. These parasites together with the prevalence of Trichodina spp., ecto-/endoparasite ratio and endoparasite diversity illustrate a significant change in holding conditions over the years. This can be either referred to a definite change in management methods such as feed use and fish treatment, or a possible transition of a relatively undisturbed marine environment into a more affected habitat. By visualizing all parameters within a single diagram, we demonstrate that fish parasites are useful bioindicators to monitor long-term change in Indonesian grouper mariculture. This also indicates that groupers can be used to monitor environmental change in the wild. Further taxonomic and systematic efforts in less sampled regions significantly contributes to this new application, supporting fish culture and environmental impact monitoring also in other tropical marine habitats

    Meso-and bathy-pelagic fish parasites at the Mid-Atlantic Ridge (MAR): Low host specificity and restricted parasite diversity

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    a b s t r a c t Seven meso-and bathy-pelagic fish species from the Mid-Atlantic Ridge (MAR) were firstly studied for fish parasites and feeding ecology. With a total of seven parasite species, the 247 meso-and bathypelagic deep-sea fish specimens belonging to the families Melamphaidae (3 spp.), Myctophidae (3 spp.) and Stomiidae (1 sp.) revealed low parasite diversity. The genetically identified nematodes Anisakis simplex (s.s.) and Anisakis pegreffii from the body cavity, liver and muscles of Myctophum punctatum were the most abundant parasites, reaching a prevalence of 91.4% and mean intensity of 3.1 (1-14). Anisakis sp. (unidentified) infected Chauliodus sloani and Poromitra crassiceps. Bothriocephalidean and tetraphyllidean cestode larvae infected Benthosema glaciale, the latter also occurring in C. sloani and Scopelogadus beanii, at low prevalences. Adult parasites at low infection rates included the digenean Lethadena sp. (2.9%), and the two copepod species Sarcotretes scopeli (5.7%) and Tautochondria dolichoura (5.3-11.4%). The myctophid Lampanyctus macdonaldi and the melamphaid Scopelogadus mizolepis mizolepis were free of parasites. Analyses of the stomach contents revealed crustaceans, especially copepods and euphausiids for the myctophids and also amphipods for the melamphaids as predominant prey items. While all stomachs showing distinct content comprising often unidentified 'tissue' (possibly gelatinous zooplankton), only C. sloani preyed upon fish. Though this feeding habit would enable transfer of a variety of crustacean-transmitted parasites into the fish, the parasite fauna in the meso-and bathy-pelagic fish was species poor. All observed parasites showed low host specificity, demonstrating no distinct pattern of host-parasite co-evolution. The MAR is no barrier for the parasite distribution in the North Atlantic meso-and bathy-pelagial

    Effects of stocking density and grading on behaviour, cannibalism and performance of African catfish (Clarias gariepinus) fry

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    African catfish hatcheries in Europe require economical fry availability throughout the year. Purpose of this study was to identify the best suitable stocking density and appropriate grading regime for African catfish fry of around 0.1 g in 3 experiments (E1, E2 and E3). In E1, 3 stocking densities (10, 20 and 30 fry L−1) without grading were compared for behaviour, mortality, cannibals and growth. In E2, additional daily manual grading removed shooters or potential cannibals. In E3, 3 different handling procedures (manual grading on days 2, 4, 6 and 8: 2dH, manual grading on day 5: 5dH, self-grading on day 5: 5dS) under highest stocking density (30 fish L−1) were applied. Each experiment lasted 10 days and the fish had a mean initial weight of 0.08, 0.06 and 0.06 g fish−1, respectively. In E1 and E2 stock activity increased with increasing stocking density but aggressive behaviour was lowest at the higher stocking densities. The stocking density had no significant effect on mortality rates or growth performance from 10 to 30 fish L−1 between groups. However, regular removal of cannibals reduced the total mean mortality rate from 25 % in E1 to less than 5 % in E2 and E3. The mean feed conversion ratio (FCR) improved from 0.68 in E1 to ≤ 0.55 in E2 and E3. The tested handling procedures revealed no significant differences in fry behaviour and performance, while final stocking densities increased with decreasing handling stress. This suggests that African catfish fry of about 0.1 g are kept optimally at high stocking densities of 30 fish L−1 or 30,000 fry m−3 inside regular breeding containments, with effective self-grading every 5 days in order to reduce total mortality, maximize production and minimize the amount of labor

    Parasites of the Antarctic rattail Macrourus whitsoni (Regan, 1913) (Macrouridae, Gadiformes).

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    A total of 386 Macrourus whitsoni from Antarcticwaters were examined for ecto- and endoparasites.Sixty-five M. whitsoni collected near Halley Bay(Weddell Sea) and 321 specimens from the continentalslope off King George Island (South Shetland Islands)were studied for sphyriid copepods directly after beingcaught. A subsample of 25 specimens from the WeddellSea and of 9 specimens from King George Island werestudied for the presence of other metazoan parasites.Twenty-two species were found, including one myxozoan,six digeneans, one monogenean, three cestodes,seven nematodes, one acanthocephalan and three crustaceanspecies/taxa. While Auerbachia monstrosa andCapillaria sp. are reported for the first time from aroundthe Antarctic, the other parasites have been recordedearlier in the Southern Ocean. Many parasite speciesfound have a wide zoogeographical range and a lowhost-specificity. The parasite fauna of M. whitsoni revealedseveral similarities with its congeners M. carinatusand M. holotrachys from Antarctic and sub-Antarctic waters. This can be explained by a wide hostrange of many macrourid deep-sea parasites, togetherwith an overlap in distribution patterns of their hosts.Other supporting factors are host migration and a closephylogenetic relationship between the hosts, whichenable the parasites to infest all three macrourids. Eightnew host and 14 new locality records are established

    Aquaponics (s.l.) Production of Spearmint (Mentha spicata) with African Catfish (Clarias gariepinus) in Northern Germany

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    Aquaponics production of spearmint (Mentha spicata) was evaluated under commercial grow-out conditions of African catfish (Clarias gariepinus) in Northern Germany (Mecklenburg-Western Pomerania). Fish batch production under different stocking densities in an extensive aquacultural unit (EAU) and an intensive aquacultural unit (IAU) was connected to conventional plant cultivation on ebb-and-flood planting tables and compared to a liquid fertilizer control. The best growth parameters of M. spicata were found under the intensive stocking density of C. gariepinus (IAU), resulting in a plant leaf area of 10.9 ± 2.5 cm2, leaf length of 8.6 ± 1.6 cm, and a cut fresh biomass from aboveground of 31.8 ± 13.8 g/plant, compared to the EAU (5.6 ± 2.1 cm2; 5.4 ± 1.4 cm; 17.4 ± 4.7 g/plant) and the control (5.7 ± 2.2 cm2; 5.5 ± 1.4 cm; 11.2 ± 5.3 g/plant). The fresh biomass of the whole plants was not significantly different between the EAU (165.5 ± 71.7 g/plant) and the IAU (190.7 ± 105.6 g/plant), though the latter gained more weight. The initial fish number ratio between the EAU and the IAU of 1/4 increased the M. spicata leaf area by twofold in the IAU. Our results demonstrate that aquaponics (s.l.) production of M. spicata is possible under the direct use of effluent waters from intensive African catfish cultivation without the addition of any liquid fertilizer
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