Experimental infection/transmission of sculpins ( Myoxocephalus scorpius ) and cod ( Gadus morhua ) by sealworm ( Pseudoterranova decipiens ) larvae

1997 ◽  
Vol 83 (4) ◽  
pp. 380-382 ◽  
Author(s):  
Tor Jensen
Keyword(s):  
Experimental Infection ◽  
Gadus Morhua ◽  
Infection Transmission ◽  
Pseudoterranova Decipiens ◽  
Myoxocephalus Scorpius

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.

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 Surveys of larval sealworm (Pseudoterranova decipiens) infection in various fish species sampled from Nova Scotian waters between 1988 and 1996, with an assessment of examination procedures

2001 ◽  
Vol 3 ◽  
pp. 57 ◽  
Author(s):  
G McClelland ◽  
DJ Martell
Keyword(s):  
Gadus Morhua ◽  
Gulf Of Maine ◽  
New Host ◽  
Pseudoterranova Decipiens ◽  
Infection Parameters ◽  
Routine Inspection ◽  
Frozen Fish ◽  
Nova Scotian ◽  
New Host Records ◽  
Benthic Consumers

Between November 1988 and October 1996, >10,000 fish from the Breton Shelf, Sable Island Bank and the northeastern Gulf of Maine were examined for larval anisakines. Larval sealworm, Pseudoterranova decipiens, occurred in 30 of 39 species surveyed, including 8 new host records, Enchelyopus cimbrius, Lycodes reticulatus, Eumesogrammus praecisus, Lumpenus lumpretaeformis, Lumpenus maculatus, Cryptacanthodes maculatus, Artediellus atlanticus and Triglops murrayi. The parasite was most prevalent and abundant in mature demersal piscivores and benthic consumers. Sealworm densities (nr kg-1 host wt.), however, were greatest in small benthophagous fish including mature E. cimbrius, A. atlanticus, T. murrayi and Aspidophoroides monopterygius, and juvenile Hippoglossoides platessoides. ANOVA revealed that geographical disparities in sealworm prevalence and abundance were highly significant in 14 of 20 species tested, although significant disparities between samples from each of the three areas were evident only in H. platessoides. Almost invariably, infection parameters were greatest in fish from Sable Island Bank. ANOVA also indicated that sealworm prevalence and/or abundance increased significantly in Sable Island Bank populations of Gadus morhua, H. platessoides, and seven other species between 1985-1986 and 1989-1990. Routine examinations, in which host flesh was sliced and candled, proved as efficacious as digestion in warm (35° C) pepsin-HCl for detection of larval sealworm in the flesh of large frozen fish. Procedures employing fresh (iced) samples, digestion at ambient temperature and microscopy are recommended, however, for surveys of small benthic consumers. Many of the sealworm infecting the latter hosts are tiny (2 to 10 mm in length) nematodes, which escape detection by routine inspection, and may not survive in warm pepsin-HCl solution.

Experimental Infection and Pathogenesis of Viral Erythrocytic Necrosis (VEN) in Atlantic Cod, Gadus morhua

1986 ◽  
Vol 43 (5) ◽  
pp. 945-951 ◽  
Author(s):  
Paul W. Reno ◽  
Katherine Kleftis ◽  
Stuart W. Sherburne ◽  
Bruce L. Nicholson
Keyword(s):  
Infection Rate ◽  
Experimental Infection ◽  
Temporal Pattern ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Infected Fish

Mature Atlantic cod (Gadus morhua) were experimentally infected with viral erythrocytic necrosis (VEN) by inoculation with washed erythrocytes or ceil-free homogenates of erythrocytes from naturally infected fish. Approximately one third of the animals exposed exhibited active infections. The temporal pattern of infection was similar between naturally infected and experimentally infected fish. One to two months after infection, immature erythrocytes began to show clear evidence of VEN followed by a rapid increase in the proportion of infected immature erythrocytes, frequently reaching 100%. A subsequent dramatic drop in infection of immature erythrocytes occurred, coinciding with an increase of infection in mature erythrocytes. Significant erythroblastosis occurred when the overall erythrocyte infection rate reached approximately 10%, but none of the newly generated erythrocytes appeared infected. The peak infection rate (40–60% of erythrocytes infected) declined slowly and the infection, in most instances, was completely resolved.

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.

fish–macrofauna interactions in a kelp (laminaria hyperborea) forest

2005 ◽  
Vol 85 (5) ◽  
pp. 1279-1286 ◽  
Author(s):  
k.m. norderhaug ◽  
h. christie ◽  
j.h. fosså ◽  
s. fredriksen
Keyword(s):  
Fish Species ◽  
Diurnal Cycle ◽  
Gadus Morhua ◽  
Kelp Forest ◽  
Stomach Contents ◽  
Laminaria Hyperborea ◽  
Lacuna Vincta ◽  
Important Prey ◽  
Myoxocephalus Scorpius ◽  
Labrus Bergylta

predator–prey interactions between fish and macrofauna in kelp (laminaria hyperboea) forest were examined. fish were caught in gill-nets and fish traps at two sites and throughout the diurnal cycle. their stomach contents were analysed. the most abundant fish species, except pollachius virens, were caught in larger numbers at night than during daytime. the examined fish fed throughout the diurnal cycle and kelp-associated fauna were found to be important prey. pollachius virens was caught in the same numbers throughout the diurnal cycle and contained mainly pelagic prey, in larger numbers during the day than at night. small labrids were specialists, feeding mainly on the two numerically dominant kelp-associated gastropods rissoa parva and lacuna vincta. the larger labrus bergylta, gadus morhua and myoxocephalus scorpius were generalists, feeding on a large range of kelp-associated invertebrates. some fish species showed preference for particular vertical levels when feeding in the kelp forest. the most mobile and/or the largest invertebrates were most heavily preyed upon.

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.

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