scholarly journals Distribution and abundance of sealworm (Pseudoterranova decipiens) and other anisakid nematodes in fish and seals in the Gulf of St. Lawrence: potential importance of climatic conditions

2001 ◽  
Vol 3 ◽  
pp. 113 ◽  
Author(s):  
David J Marcogliese
Keyword(s):  
Gadus Morhua ◽  
Atlantic Cod ◽  
Climatic Conditions ◽  
Pseudoterranova Decipiens ◽  
Nematode Abundance ◽  
Contracaecum Osculatum ◽  
Myoxocephalus Scorpius ◽  
Longhorn Sculpin ◽  
Anisakid Nematodes ◽  
Seal Diet

Prevalence and abundance of sealworm (Pseudoterranova decipiens) and other anisakid nematodes were determined in a variety of fishes from the Gulf of St. Lawrence in 1990 and 1992. Sealworm abundance and prevalence were also determined in three species of seals in the Gulf between 1988 and 1992. Atlantic cod (Gadus morhua) and shorthorn (Myoxocephalus scorpius) and longhorn sculpin (M. octodecemspinosus) were the fishes most heavily infected with sealworm. Grey seals(Halichoerus grypus) proved to be the most important definitive hosts for sealworm in the Gulf. Abundance of sealworm increased, whereas that of Anisakis simplex and contracaecine nematodes decreased, from north to south in the Gulf. Abundance of sealworm increased compared to earlier surveys in most areas of the Gulf, but decreased in both cod and grey seals during the course of this study. In contrast, abundance of Contracaecum osculatum and Phocascaris spp. in grey seals and cod continued to increase during the study period. Observed increases of nematodes are attributed to growing populations of grey seals (for sealworm) and harp seals (for Contracaecinea). Levels of A. simplex remained relatively constant between 1988 and 1992 in both grey seals and cod. There is no evidence suggesting that observed patterns in nematode abundance were due to changes in grey seal diet. Nor was there any evidence of competition between P. decipiens and C. osculatum in grey seals affecting either sealworm abundance or fecundity. The trends detected herein are attributed to climatic events in the Gulf of St. Lawrence, where water temperatures in the cold intermediate layer consistently decreased between 1986 and 1994. It is suggested that low temperatures inhibited development and hatching of sealworm eggs, but not those of C. osculatum.

scholarly journals Contracaecum osculatumand other anisakid nematodes in grey seals and cod in the Baltic Sea: molecular and ecological links

2017 ◽  
Vol 92 (1) ◽  
pp. 81-89 ◽  
Author(s):  
S. Zuo ◽  
P.W. Kania ◽  
F. Mehrdana ◽  
M.H. Marana ◽  
K. Buchmann
Keyword(s):  
Baltic Sea ◽  
Gadus Morhua ◽  
Final Host ◽  
The Baltic Sea ◽  
Fish Stocks ◽  
Pseudoterranova Decipiens ◽  
Contracaecum Osculatum ◽  
The Baltic ◽  
The Impact ◽  
Anisakid Nematodes

AbstractPopulations of grey seals (Halichoerus grypus), sprats (Sprattus sprattus) and cod (Gadus morhua) in the Baltic Sea are relatively stationary. The present work, applying classical and molecular helminthological techniques, documents that seals and cod also share a common parasite, the anisakid nematodeContracaecum osculatum, which uses seals as the final host and fish as transport hosts. Sequencing mitochondrial genes (COX1andCOX2) in adult worms from seals and third-stage larvae from livers of Baltic fish (sprats and cod), showed that all gene variants occur in both seals and fish. Other anisakid nematodesPseudoterranova decipiensandAnisakis simplexare also found in both seals and cod in the Baltic Sea, but at much lower rates. The Baltic grey seal population was left at a critically low level (comprising a few hundred individuals) during the latter part of the 20th century, but since the year 2000 a marked increase in the population has been observed, reaching more than 40,000 individuals at present. Ecological consequences of the increased seal abundance may result from increased predation on fish stocks, but recent evidence also points to the influence of elevated parasitism on fish performance.Contracaecum osculatumlarvae preferentially infect the liver of Baltic cod, considered a vital organ of the host. Whereas low prevalences and intensities in cod were reported during the 1980s and 1990s, the present study documents 100% prevalence and a mean intensity of above 80 worms per fish. Recent studies have also indicated the zoonotic potential ofC. osculatumlarvae in fish, following the consumption of raw or under-cooked fish. Therefore the present work discusses the impact of parasitism on the cod stock and the increasing risk for consumer health, and lists possible solutions for control.

Corynosoma wegeneri (Acanthocephala: Polymorphida) and Pseudoterranova decipiens (Nematoda: Ascaridoidea) Larvae in Scotian Shelf Groundfish

1992 ◽  
Vol 49 (10) ◽  
pp. 2062-2069 ◽  
Author(s):  
David J. Marcogliese ◽  
Gary McClelland
Keyword(s):  
Gadus Morhua ◽  
Atlantic Cod ◽  
Host Record ◽  
Melanogrammus Aeglefinus ◽  
Scotian Shelf ◽  
New Host ◽  
New Host Record ◽  
Pseudoterranova Decipiens ◽  
Sea Raven ◽  
Longhorn Sculpin

We examined larvae of the seal parasites Corynosoma wegeneri and Pseudoterranova decipiens in various fish species collected from Western and Sable Island banks between February 1989 and October 1990. Atlantic cod (Gadus morhua), haddock (Melanogrammus aeglefinus), American plaice (Hippoglossoides platessoides), yellowtail flounder (Pleuronectes ferrugineus), windowpane (Scophthalmus aquosus), longhorn sculpin (Myoxocephalus octodecemspinosus), and sea raven (Hemitripterus americanus) were infected by both parasites, longhorn sculpin being a new host record for C. wegeneri. Only C. wegeneri occurred in winter flounder (Pleuronectes americanus), and neither parasite was found in northern sand lance (Ammodytes dubius) or capelin (Mallotus villosus). The two parasites were most numerous in sea raven and longhorn sculpin. Corynosoma wegeneri was more prevalent in fish sampled in 1989–90 than in previous surveys of Atlantic cod and haddock from the Scotian Shelf. Pseudoterranova decipiens and C. wegeneri occurred throughout the sampling area, but small fishes in the vicinity of Sable Island had the heaviest sealworm infections, and both parasites in longhorn sculpin declined with distance from Sable Island. Increases of C. wegeneri in groundfish, like recent increased levels of P. decipiens infection on the Scotian Shelf, can be attributed to the dramatic growth of the grey seal (Halichoerus grypus) population on Sable Island.

Influence of climatic changes on the parasites of Atlantic cod Gadus morhua off coastal Labrador, Canada

2006 ◽  
Vol 80 (2) ◽  
pp. 193-197 ◽  
Author(s):  
R.A. Khan ◽  
C.V. Chandra
Keyword(s):  
North Atlantic ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Age Groups ◽  
Climatic Conditions ◽  
Otter Trawl ◽  
Commercial Fishery ◽  
Metazoan Parasites ◽  
Mean Values ◽  
The North

AbstractA study was conducted in 2000 and 2003, following the collapse of the commercial fishery in 1990, to compare metazoan parasites of Atlantic cod Gadus morhua, captured off coastal Labrador, with samples taken in 1980 and 1986. Fish were captured by otter trawl offshore in the North Atlantic Fish Organisation subarea 2J. Parasites were removed from the digestive tract, stained, identified and compared between the different groups. Both the prevalence and mean abundance of trematodes, larval nematodes and E. gadi were significantly lower in fish taken in 2000 and 2003 than in 1980. While mean values of trematodes and nematodes declined in 1986, those of Echinorhynchus gadi remained unchanged in 1986 and 1990. Four-year-old cod sampled in 1990 harboured significantly fewer E. gadi than older age groups. The most commonly occurring trematodes included Podocotylereflexa, Lepidapedon elongatum, Derogenes varicus and Hemiurus levinseni while the larval nematode, Anisakis sp. was predominant. Comparison of offshore samples taken in 2000 and 2003 with others taken in previous years suggests an overall decline of parasites coincident with a change in climatic conditions, the absence of a major food source, namely capelin Mallotus villosus, of cod and ultimately the decline of the Labrador population.

Anisakids of seals found on the southern coast of Baltic Sea

2014 ◽  
Vol 59 (1) ◽  
Author(s):  
Michał Skrzypczak ◽  
Jerzy Rokicki ◽  
Iwona Pawliczka ◽  
Katarzyna Najda ◽  
Joanna Dzido
Keyword(s):  
Baltic Sea ◽  
Life Stage ◽  
Adult Life ◽  
Sensu Stricto ◽  
Halichoerus Grypus ◽  
Slight Excess ◽  
Pseudoterranova Decipiens ◽  
Pusa Hispida ◽  
Contracaecum Osculatum ◽  
Anisakid Nematodes

AbstractIn the present study 5 grey seals (Halichoerus grypus), 3 common seals (Phoca vitulina) and 1 ringed seal (Pusa hispida) bycaught or stranded on the Polish Baltic Sea coast in years 2000-2006 were investigated for the infestation of parasitic anisakid nematodes. 749 of anisakids were found. The most common were: Contracaecum osculatum (59.3%) and Pseudoterranova decipiens (31.0%). There were also small numbers of Anisakis simplex (0.8%). After performing RFLP three sibling species were found. C. osculatum was identified as C. osculatum C, P decipiens was identified as P. decipiens sensu stricto and A. simplex — A. simplex sensu stricto. Nematodes found in seals were mostly in L4 and adult life stage — both of them were equal with some minor variations among the specimens. Sex ratio was also equal, but there was slight excess of males in some cases. There was a minority of L3 larvae belonging to A. simplex species (0.8%).

Sealworm (Pseudoterranova decipiens) infections in demersal fish from two areas in Norway

1994 ◽  
Vol 72 (4) ◽  
pp. 598-608 ◽  
Author(s):  
Tor Jensen ◽  
Karin Andersen ◽  
Sophie des Clers
Keyword(s):  
Gadus Morhua ◽  
Demersal Fish ◽  
Phoca Vitulina ◽  
Halichoerus Grypus ◽  
Shallow Waters ◽  
Benthic Fish ◽  
Pseudoterranova Decipiens ◽  
Average Abundance ◽  
Myoxocephalus Scorpius ◽  
Southern Norway

Fish from Torbjørnskjær, in the outer Oslofjord in southern Norway, and from Vega in Nordland in central Norway were examined for infections of the larval nematode Pseudoterranova decipiens transmitted by seals. Three sites were sampled between 1990 and 1992, two (S1 and S2) in Torbjørnskjær and one (S3) in Vega, and 3361 fish were examined in total. In Torbjørnskjær, fish were collected from shallow waters (S1) near skerries where a colony of common seals (Phoca vitulina) regularly haul out, and from deeper waters outside these skerries (S2). In Vega, an extensive zone of rocks and shallow water is inhabited by a colony of grey seals (Halichoerus grypus) and some common seals. In Vega, fish were caught from the littoral zone to 40–50 m depth, except for cusk (Brosme brosme), which were caught in deeper waters. Only demersal and benthic fish were infected in both areas, infection levels being highest in shallow waters close to the rocks (sites S1 and S3). Sculpins (Myoxocephalus scorpius) had the highest infection levels (an average abundance of 36 and 23 worms per fish, respectively), with cod (Gadus morhua) and cusk also heavily infected; the latter species was found only at Vega. Two somewhat different transmission routes to seals are suggested for the two areas.

Marine Fish Tissue Culture

1963 ◽  
Vol 20 (3) ◽  
pp. 679-684 ◽  
Author(s):  
P. M. Townsley ◽  
H. G. Wight ◽  
M. A. Scott
Keyword(s):  
Tissue Culture ◽  
Marine Fish ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
White Perch ◽  
Kidney Tissue ◽  
Fish Tissue ◽  
Pseudopleuronectes Americanus ◽  
Myoxocephalus Scorpius ◽  
Raja Radiata

Cell proliferation of tissue explants of different organs from marine fish has been achieved in a nutrient solution composed of Medium 199 plus 10% human serum. Fin, spleen, heart, kidney, liver, gonad, brain, uterus, and thymus tissues have been cultured. The tissues were obtained from sexually mature Atlantic cod (Gadus morhua), white perch (Roccus americanus) winter flounder (Pseudopleuronectes americanus), thorny skate (Raja radiata), American goosefish (Lophius americanus), pollock (Pollachius virens), and shorthorn sculpin (Myoxocephalus scorpius). An actively dividing cell culture of flounder kidney cells prepared by mechanical disruption of the kidney tissue was maintained through serial transfers over several months. Heart explants from the cod vigorously pulsated in tissue culture.

Parasites as biological indicators of stocks of Atlantic cod (Gadus morhua) off Newfoundland, Canada

1995 ◽  
Vol 52 (S1) ◽  
pp. 195-201 ◽  
Author(s):  
R.A. Khan ◽  
C. Tuck
Keyword(s):  
Continental Shelf ◽  
North Atlantic ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Biological Indicators ◽  
Blood Feeding ◽  
Size Class ◽  
Paired Comparisons ◽  
Pseudoterranova Decipiens

Atlantic cod (Gadus morhua) were collected from six locations on the continental shelf off Newfoundland, Canada, including one inshore area and examined for parasites from 1981 to 1983. The protozoan Loma branchialis was more prevalent in North Atlantic Fisheries Organization (NAFO) areas 3Pn-4R (Gulf of St. Lawrence) and 2J-3K (Labrador), whereas the acanthocephalan Echinorhynchus gadi was more abundant in the latter than in other locations. Similarly, the prevalence and (or) abundance of the fillet-inhabiting larval nematode Pseudoterranova decipiens and the blood-feeding copepod Lernaeocera branchialis were significantly greater in fish from 3Ps (St. Pierre Bank) and 3Pn-4R than from all adjacent areas. Gastrointestinal ascaridoid nematodes were more abundant in 3M (Flemish Cap) cod than in other localities. No differences in the prevalence and abundance of E. gadi were detected in samples in relation to sex or size class. Paired comparisons of transformed data for the different parasite taxa revealed that there were more significant differences than similarities in cod sampled from adjacent NAFO divisions. These observations based on selected parasites (Loma branchialis, Trypanosoma murmanensis, Myxidium gadi, P. decipiens, gastrointestinal ascaridoid nematodes, E. gadi, and Lernaeocera branchialis) support the view that discrete stocks of cod inhabit the Newfoundland–Labrador continental shelf.

Identification of larval Contracaecum osculatum s.l. and Phocascaris sp. (Nematoda: Ascaridoidea) from marine fishes by allozyme electrophoresis and discriminant function analysis of morphometric data

1995 ◽  
Vol 52 (S1) ◽  
pp. 116-128 ◽  
Author(s):  
John Brattey
Keyword(s):  
Discriminant Function ◽  
Discriminant Function Analysis ◽  
Newfoundland And Labrador ◽  
Biochemical Markers ◽  
Gadus Morhua ◽  
Function Analysis ◽  
Nematode Species ◽  
Contracaecum Osculatum ◽  
Myoxocephalus Scorpius ◽  
Taxonomic Groups

Biochemical markers (allozymes) were used to identify third-stage larvae of nematodes from the Contracaecum osculatum s.l. – Phocascaris sp. complex found in five marine fish species (Hippoglossoides platessoides, Gadus morhua, Mallotus villosus, Myoxocephalus scorpius, Pleuronectes americanus) collected off Newfoundland and Labrador. Three taxonomic groups, genetically identical to adult C. osculatum A, C. osculatum B, and Phocascaris sp. previously reported from North Atlantic seals, were found. Among the 859 larvae examined, C. osculatum B was most common (74.2%), particularly in H. platessoides (79.4% of 501 larvae), G. morhua (88.8% of 160), M. scorpius (87.5% of 32), and P. americanus (100.0% of 20), but Phocascaris sp. was more numerous in M. villosus (66.4% of 146). Contracaecum osculatum A was found only in H. platessoides (15% of 501). Discriminant function analysis revealed differences in shape among the nematode species. Larvae of Phocascaris sp. and C. osculatum B can generally be distinguished using three measurements and classified according to coefficients for quadratic discriminant functions, but larvae of C. osculatum A could not be reliably distinguished from the other two species. A simpler, more rapid method of screening biochemical markers, employing a cellulose acetate support medium, is also described.

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