Helminth parasites of the alimentary tract of the hakes (Merluccius, Urophycis, Phycis: Teleostei) of the Scotian Shelf

1987 ◽  
Vol 65 (2) ◽  
pp. 304-311 ◽  
Author(s):  
J. S. Scott

Alimentary tracts of the five common hakes of the Scotian shelf (Urophycis chuss, Urophycis tenuis, Phycis chesteri, Merluccius bilinearis, Merluccius albida) were examined for helminth parasites. A total of 29 species was found: 17 Digenea, 4 Cestoda, 6 Nematoda, 2 Acanthocephala. The greatest numbers of species were found in the closely associated U. tenuis (25) and U. chuss (19). Phycis chesteri hosted a moderate number (14) but included 3 digeneans that are typical of deep water (Anomalotrema koiae, Lethadena profunda, Paraccacladium jamiesoni) not found in the other hakes. The merlucciids were characterized by low numbers of parasite species, particularly of digeneans, but showed high prevalence of the host-specific cestode Clestobothrium crassiceps. The effects of geographic distribution, fish length, and depth of capture on parasite prevalence were examined for those parasites that were adequately represented. There was little difference in geographical distribution except in the case of C. crassiceps, in which distribution suggested a separate population of M. bilinearis on the Scotian Shelf from that of the Gulf of Maine. Fish length and depth of capture had little effect on parasite prevalence.

1988 ◽  
Vol 66 (3) ◽  
pp. 617-621 ◽  
Author(s):  
J. S. Scott

Examination of alimentary tracts of 319 redfish (Sebastes fasciatus) from the Scotian Shelf, Bay of Fundy, and eastern Gulf of Maine yielded 13 helminth species: 7 Digenea, 3 Cestoda, 2 Nematoda, and 1 Acanthocephala. Total species composition was virtually identical with that found in the redfish of the Labrador–Newfoundland area. Prevalence and intensity of infection were low and showed little variation with area or fish length except in the case of the nematodes Anisakidae for which low prevalence and intensity (3.9 and 1.0, respectively) in the eastern Gulf of Maine contrasted with higher values (39.1–71.4 and 1.7–7.7, respectively) in the remainder of the survey area. The general pattern of species numbers was low numbers (2–4) in the fish of the Gulf of Maine and southwest Nova Scotia, and higher numbers (8–13) in those of the central and northeast Scotian Shelf. Small- to intermediate-sized fish contained more species (7–12) than the largest fish (4). The combination of exceptionally low prevalence of Anisakidae and low parasite species numbers in redfish of the eastern Gulf of Maine area suggests that the stock there is distinct from those of the Scotian Shelf and Bay of Fundy.


1989 ◽  
Vol 67 (6) ◽  
pp. 1476-1481 ◽  
Author(s):  
James S. Scott ◽  
Shelley A. Bray

Examination of the alimentary tracts of 272 Atlantic halibut (Hippoglossus hippoglossus (L.)) and 71 Greenland halibut (Reinhardtius hippoglossoides (Walbaum)) from the Scotian Shelf yielded a total of 25 helminth parasite species, 23 from H. hippoglossus (16 Digenea, 3 Cestoda, 2 Acanthocephala, 2 Nematoda) and 16 from R. hippoglossoides (11 Digenea, 3 Cestoda, 1 Acanthocephala, 1 Nematoda). Parasite prevalence and intensity were low (< 50% and < 10%, respectively) in both hosts, except for Derogenes varicus and Steganoderma formosum in H. hippoglossus and anisakid nematodes in R. hippoglossoides. Consideration of change in parasite prevalence and mean intensity in relation to fish length and diet suggests fish prey as transport hosts for D. varicus in larger halibuts, and crustaceans as the intermediate hosts for S. formosum before transmission to its principal host, H. hippoglossus. Geographical change in parasite prevalence and intensity was in the form of southwest to northeast clines along the Shelf, probably related to environmental factors. There was no evidence for stock differentiation in either of the hosts based on parasite fauna.


1985 ◽  
Vol 63 (7) ◽  
pp. 1695-1698 ◽  
Author(s):  
J. S. Scott

Examination of the alimentary tracts of 456 pollock (Pollachius virens L.) revealed the presence of 15 helminth species or groups representing four phyla. Prevalence ranged from 76.6 in anisakid nematodes to negligible levels (<1.0) in some other species, with "ubiquitous" marine parasites Derogenes varicus, Hemiurus levinseni, anisakid nematodes, and Echinorhynchus gadi showing highest values. Changes in prevalence were related to a change from a largely crustacean diet to a largely fish diet with increasing fish length. Differences in prevalence of the more common parasites between the central and southwestern Scotian Shelf support evidence for separate pollock populations in the two areas.


2020 ◽  
Vol 94 ◽  
Author(s):  
I. Beveridge

Abstract The gastrointestinal helminth parasites of 170 common wallaroos or euros, Osphranter robustus (Gould), collected from all mainland states in which the species occurs as well as the Northern Territory, are presented, including previously published data. A total of 65 species of helminths were encountered, including four species of anoplocephalid cestodes found in the bile ducts and small intestine, and 61 species of strongylid nematodes, all but two of which occurring in the stomach, and with the remainder occurring in the terminal ileum, caecum and colon. Among the mainland subspecies of O. robustus, 52 species of helminths were encountered in O. r. robustus, compared with 30 species in O. r. woodwardi and 35 species in O. r. erubescens. Of the parasite species encountered, only 17 were specific to O. robustus, the remaining being shared with sympatric host species. Host-specific species or species occurring in O. robustus at a high prevalence can be classified as follows: widely distributed; restricted to northern Australia; restricted to the northern wallaroo, O. r. woodwardi; found only in the euro, O. r. erubescens; found essentially along the eastern coast of Australia, primarily in O. r. robustus; and species with highly limited regional distributions. The data currently available suggest that the acquisition of a significant number of parasites is due to co-grazing with other macropodids, while subspeciation in wallaroos as well as climatic variables may have influenced the diversification of the parasite fauna.


2004 ◽  
Vol 78 (4) ◽  
pp. 297-303 ◽  
Author(s):  
S. Guillen-Hernandez ◽  
P.J. Whitfield

AbstractAn analysis was undertaken of intestinal helminth communities in flounderPlatichthys flesusfrom two sites on the River Thames. A comparison was made between helminth community richness and diversity from these sites at the component and infracommunity levels. At the component community level, a richer and more diverse parasite community was found in flounder from the Tilbury location (marine influence) than that from the Lots Road location (freshwater influence). At the infracommunity level, more parasite species and parasite individuals per host were found at Lots Road and the percentage of similarity values were low at both locations. Helminth species with high prevalence values in the parasite communities of the flounder are the dominant species in any individual fish, harbouring multi-specific infections. The presence of more invertebrate species, which are intermediate hosts in the helminth life cycle in the Thames, fish vagility and the high prevalence and abundance values ofPomphorhynchus laevisin the flounder, may explain the differences between the two locations.


1982 ◽  
Vol 60 (11) ◽  
pp. 2804-2811 ◽  
Author(s):  
J. S. Scott

Prevalence of digenean parasites in four major flatfishes of the Scotian Shelf and southern Gulf of St. Lawrence, American plaice (Hippoglossoides platessoides), yellowtail flounder (Limanda ferruginea), witch flounder (Glyptocephalus cynoglossus), and winter flounder (Pseudopleuronectes americanus), is compared between hosts in relation to geographic distribution, season, feeding behavior, and fish length. The 13 parasite species indicate overlap of feeding habits among hosts but also considerable diversity in feeding behavior, supporting the evidence from examination of stomach contents. Prevalence of digeneans in different final hosts varied between geographic areas and may be used to characterize the populations of the comparatively sedentary flatfish populations. Seasonal variation in prevalence was consistent from area to area but differed between parasites, from the expected increase in summer in some, concomitant with increased feeding, to a winter increase in others, probably related to a seasonal change of diet. Fish length had little effect on parasite prevalence in yellowtail flounder and witch flounder but had a notable effect on plaice and winter flounder from the Gulf of St. Lawrence, again apparently related to change of diet.


1981 ◽  
Vol 59 (12) ◽  
pp. 2244-2252 ◽  
Author(s):  
J. S. Scott

Nineteen species of alimentary tract (including gall and swim bladders) parasites were found in haddock (Melanogrammus aeglefinus) on the Scotian Shelf, of which eight species were new Canadian records for haddock. Prevalence ranged up to 82.3% for Hysterothylacium aduncum and 70.9% for Echinorhynchus gadi, the most abundant parasites, with Lepidapedon rachion and Echinorhynchus gadi showing highest intensities (14.9 and 76.5, respectively). Prevalence decreased from summer to winter, was not related to sex of host, but showed geographical variation characterizing different geographical areas. The Bay of Fundy showed higher nematode and lower trematode abundance than the offshore Scotian Shelf which showed general clines in abundance of several species from southwest to northeast. There was no evidence of growth-related change in parasite prevalence in adult fish, but the parasite complex of young-of-the-year haddock indicated planktonic feeding, in contrast with benthic feeding in the adult. Site specificity within the alimentary tract was shown by several species. Echinorhynchus gadi changed its site seasonally. Lepidapedon rachion showed size differentiation in the gut, smaller trematodes occupying more anterior sites than larger. Only two parasite species offer prospects as biological tags, L. rachion and Myxidium bergense, but all may provide evidence of ecological, behavioral, seasonal and developmental changes in the host.


2021 ◽  
Vol 18 (1) ◽  
pp. 8-18
Author(s):  
O. Edo-Taiwo ◽  
M.S.O. Aisien

The parasitofauna of ground-dwelling anurans from pesticide-treated cocoa plantations (CP) in Ojo Camp, Ugboke, Edo State of Nigeria were investigated and compared with those recovered from host specimens collected from the village settlement (VS). The anurans were caught by hand following visual or acoustic location. The anurans encountered in both the VS and the CP included Aubria subsigillata, Hylarana spp. (H. albolabris and H. galamensis), Sclerophrys spp. (S. maculata and S. regularis), Ptychadena spp. (P. aequiplicata, P. longirostris, P. mascareniensis, P. oxyrhynchus and P. pumilio) and Hoplobatrachus occipitalis. Hylarana galamensis, Ptychadena spp. and Sclerophrys spp. were encountered in the VS and the CP while Aubria subsigillata, H. albolabris and H. occipitalis occurred only in the CP. The helminth parasites recovered included four cestode species (adult of Cylindrotaenia jaegerskioeldi and three encysted  proteocephalid larvae), five Polystoma spp. 11 species of digeneans and 19 nematode species. More parasite species were recovered from toads collected from the VS; parasite prevalence was generally low in both habitats but the intensity of infection was higher in the specimens collected from the VS. Although cip A. subsigillata and H. ocitalis both occurred in the CP, A. subsigillata was the more susceptible host of the two, harbouring 16 helminth parasites as against four from H. occipitalis. Polystomes were recovered from H. albolabris and H. galamensis in addition to Diplodiscus fischthalicus and Mesocoelium spp. Infections occurred  mostly among the Ptychadeniidae collected from the CP, with prevalence ranging from 12.5% to 100% and infection intensity from 1.0 to 13.0. The generally low parasite burden in anurans from the CP can possibly be attributed to the pesticide contamination of this habitat which may have hindered the development of the free-living stages of parasites in this milieu. Keywords: Anurans; cocoa plantation; pesticides; parasitofauna; prevalence; intensity.  


1975 ◽  
Vol 32 (4) ◽  
pp. 479-483 ◽  
Author(s):  
J. S. Scott

The following digenetic trematodes were found in the alimentary tract of American plaice (Hippoglossoides platessoides) from the Scotian Shelf and Gulf of St. Lawrence: Derogenes varicus, Fellodistomum furcigerum, Lecithaster gibbosus, Stenakron vetustum, Steringotrema ovacutum, Zoogonoides viviparus, Hemiurus levinseni, Otodistomum veliporum (larvae), Podocotyle atomon, Prosorhyncus squamatus.The incidence of several trematode species changed with length of fish and associated changes in the fish’s diet. Incidence of D. varicus and S. vetustum decreased with increase of host length, whereas incidence of R. ovacutum and Z. viviparus increased. Lecithaster gibbosus and S. furciger showed little change in incidence. Correlations between parasite incidence and frequency of occurrence of food items indicated that small crustaceans may be intermediate hosts for S. vetustum and D. varicus; sea urchins may be intermediate hosts for R. ovacutum and brittle stars for Z. viviparus.


1981 ◽  
Vol 59 (11) ◽  
pp. 2172-2176 ◽  
Author(s):  
Michael D. Rigby ◽  
William Threlfall

One hundred and fourteen muskrats (Ondatra zibethicus (L.)), collected between September 1977 and January 1979 in three areas of insular Newfoundland, were examined for helminths, with 11 species being found (7 Digenea, 2 Cestoda, and 2 Nematoda). Diplostomum mergi was recovered from a mammal for the first time. Distribution along the alimentary tract was examined and all helminths recovered preferred the proximal 60% of the small intestine, except Quinqueserialis quinqueserialis and Trichostrongylus calcaratus, which preferred the caecum. Adult and immature muskrats showed differences in the prevalence and intensity of infection and the adults also had larger concurrent infections. In only one case, namely Hymenolepis evaginata, was a parasite species more prevalent in one sex (the males). Small seasonal differences in prevalence and (or) intensity of infection were noted for some parasites and were related to differences in parasite burden of adult and immature hosts and water temperature. A difference in the occurrence of Digenea between sample areas was related to water pH and hardness.


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