Serial Passage of Larval Pseudoterranova decipiens (Nematoda:Ascaridoidea) in Fish

1990 ◽  
Vol 47 (4) ◽  
pp. 693-695 ◽  
Author(s):  
M. D. B. Burt ◽  
J. D. Campbell ◽  
C. G. Likely ◽  
J. W. Smith

In one experiment, 24 brook trout (Salvelinus fontinalis) in fresh water at 11 ± 1 °C were each orally infected by intubation with two third-stage larvae of "sealworm" (Pseudoterranova decipiens) harvested from the flesh of sea raven (Hemitripterus americanus) and small Atlantic cod (Gadus morhua). In a second experiment, 27 cod in sea water at 0 °C were each force fed, under anaesthesia, four P. decipiens larvae held in a capelin "purse"; these larvae were harvested from large, commercial size cod. Sequential reinvasion by the same P. decipiens larvae was achieved in both of the serial passage experiments. In brook trout, larvae sequentially reinvaded a maximum of two fish, with larvae of cod origin being the more successful at first passage (62.5%) than those of sea raven origin (31.3 and 37.5%). In cod, larvae also achieved sequential reinvasion of a maximum of two fish; the relatively lower success rates of 22.2% (first passage) and 9.1% (second passage) probably reflect the low temperature (0 °C) at which the experiment was conducted.

1966 ◽  
Vol 23 (3) ◽  
pp. 341-347 ◽  
Author(s):  
F. W. H. Beamish

Endurance was determined in relation to swimming speed and temperature for Atlantic cod, Gadus morhua Linnaeus, redfish, Sebastes marinus (Linnaeus), winter flounder, Pseudopleuronectes americanus (Walbaum), and to swimming speed at 8 C for longhorn sculpin, Myoxocephalus octodecimspinosus (Mitchill), sea raven, Hemitripterus americanus (Gmelin), and ocean pout, Macrozoarces americanus (Block and Schneider).In an activity chamber at a swimming speed of 4 body lengths per second (BL/sec) Atlantic cod swam for about equally long periods at 5 and 8 C, and redfish and winter flounder each about equally long at 5, 8, and 11 C. The pattern was similar for higher speeds. At 14 C winter flounder swam longer at 6 BL/sec than at the lower temperatures. For swimming speeds less than 4 BL/sec all species swam longer at the higher temperatures. At 8 C, the only temperature at which all species were tested, endurance at comparable swimming speeds was greatest for winter flounder, followed by cod, redfish, longhorn sculpin, ocean pout, and sea raven.


1992 ◽  
Vol 49 (10) ◽  
pp. 2062-2069 ◽  
Author(s):  
David J. Marcogliese ◽  
Gary McClelland

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.


1976 ◽  
Vol 65 (1) ◽  
pp. 131-145 ◽  
Author(s):  
E. D. Stevens ◽  
A. M. Sutterlin

1. The ability of fish gills to transfer heat was measured by applying a heat pulse to blood in the ventral aorta and measuring it before and after passing through the gills of a teleost, Hemitripterus americanus. 2. 80–90% of heat contained in the blood is lost during passage through the gills. 3. The fraction of heat not lost during passage through the gills is due to direct transfer of heat between the afferent and efferent artery within the gill bar. 4. The major fraction of metabolic heat (70 - 90%) is lost through the body wall and fins of the sea raven in sea water at 5 degrees C; the remainder is lost through the gills.


2014 ◽  
Vol 59 (2) ◽  
Author(s):  
Foojan Mehrdana ◽  
Qusay Bahlool ◽  
Alf Skovgaard ◽  
Jesper Kuhn ◽  
Per Kania ◽  
...  

AbstractA parasitological investigation was performed on a total of 5380 Atlantic cod larvae, post-larvae and small juveniles sampled from the North Sea during a period of five years. The copepod Caligus elongatus (Von Nordmann, 1832) and the nematode Hysterothylacium aduncum (Rudolphi, 1802) were found at a relatively high prevalence of infection (4.6% and 5.2%, respectively). The infection by both parasites showed annual and spatial variability. C. elongatus showed a higher prevalence in 1992 compared to the following years, whereas the prevalence of H. aduncum increased from 1992 to 2001.We observed a relation between parasite distribution and parameters such as latitude and water depth. Adult digeneans (Lecithaster gibbosus and Derogenes varicus) and larval cestodes were also found with lower infection rates. Since changes of infection levels coincided with increasing North Sea water temperature in the studied period, it is hypothesized that temperature may affect parasite population levels. However, it is likely that other environmental factors may contribute to the observed variations. Absence of infection intensities higher than one nematode per fish in small larvae and post-larvae suggests that host survival may be affected by a high infection pressure. The relatively high levels of infection in the younger stages of cod, and the annual/spatial variability of these infections should be considered in the understanding of the early life dynamics of the species.


1995 ◽  
Vol 52 (S1) ◽  
pp. 195-201 ◽  
Author(s):  
R.A. Khan ◽  
C. Tuck

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.


2003 ◽  
Vol 60 (5) ◽  
pp. 930-938 ◽  
Author(s):  
Jason S Link ◽  
Chad Demarest

Abstract The frequency and geographic distribution of trawlnet hangs from a fishery-independent survey are evaluated. The hangs data were plotted on a substratum map to confirm that many, but not all, were naturally occurring, high relief substrata. The data were also coupled with the occurrence of juvenile cod (Gadus morhua) and haddock (Melanogrammus aeglefinus) to assess the degree of association between juvenile gadoids and high relief substrata. The average minimal distance from a fish occurrence to a hang ranged from 8.1 to 12.0 km (4.4–6.5 nautical miles), well within the reported daily range of movement for these fish. A similar pattern was detected for the sea raven (Hemitripterus americanus), a predator of juvenile gadoids, confirming the location of these microhabitat foodwebs. On average, closing an area 3.7 km (2 nautical miles) around a hang will enclose 17–30% of the populations of these juvenile fish; a wider buffer (18–28 km; 10–15 nautical miles) will close a linearly increasing portion of the populations. Additionally, closing areas surrounding the hangs, particularly regions of high hang density, will help to minimize losses of or damage to fishing gear. We propose a win–win scenario by establishing or evaluating closed areas in regions with high concentrations of known hangs. This approach is widely applicable for many marine ecosystems and may help to achieve simultaneous conservation and resource management goals, whereby one can both protect pre-recruit fish and enhance the effectiveness of a fishery.


2001 ◽  
Vol 3 ◽  
pp. 113 ◽  
Author(s):  
David J Marcogliese

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.


1995 ◽  
Vol 52 (S1) ◽  
pp. 140-155 ◽  
Author(s):  
G. McClelland

Larval sealworm (Pseudoterranova decipiens, (Krabbe 1878)) were transmitted sequentially through copepods and amphipods to 12 phylogenetically diverse fish species. Although P. decipiens in amphipods were 0.82–7.08 mm long, only those ≥1.41 mm were infective to fish. Sealworm transmitted at 15 °C migrated to the musculature within 6 h in mummichog (Fundulus heteroclitus) and 12 h in rainbow smelt (Osmerus mordax) but were confined to the bolus in an Atlantic cod (Gadus morhua) stomach at 24 h. All sealworm in smelt, but only 12% of those in cod, occupied the musculature after 7 days. Death of 15 mummichog and a grubby (Myoxocephalus aenaeus) 10–20 days after exposure apparently resulted from damage to the brain, heart, aorta, liver, or spleen by feeding and migrating nematodes. Whereas 100% of the sealworm in grubby and 86–88% of those in mummichog and winter flounder (Pleuronectes americanus) were dead and encapsulated in host connective tissue after 56 days, all P. decipiens in smelt were viable and unencapsulated. With length increasing linearly at 0.421 mm day−1, sealworm larvae reached 27.29 (23.60–30.70) mm after 56 days in smelt at 15 °C. However, P. decipiens, which escaped the host tissue response in mummichog and flounder, were only 10.14 (6.00–21.80) and 12.42 (9.53–14.40) mm in length, respectively.


1991 ◽  
Vol 48 (9) ◽  
pp. 1623-1628 ◽  
Author(s):  
N. R. Ramakrishna ◽  
M. D. B. Burt

The histopathology of Pseudoterranova decipiens (L3) in experimentally infected rainbow trout (Oncorhynchus mykiss) and naturally infected Atlantic cod (Gadus morhua) was similar. The chronic granulomatous inflammatory reaction included polymorphonuclear neutrophils, macrophages, lymphocytes, epithelioid cells, and fibroblasts. Giant cells were also found but only in the experimentally infected rainbow trout. Mature capsules around the larvae consisted of an inner layer, composed of macrophages which underwent epithelioid transformation and later gradually degenerated, and an outer layer, composed of fibroblasts and collagen fibres. A layer of lipofuscin was adjacent to the parasite in older cod infections but this was absent in all of the newly formed capsules in the experimentally infected rainbow trout.


1991 ◽  
Vol 48 (9) ◽  
pp. 1800-1803 ◽  
Author(s):  
Tracey E. Appleton ◽  
M. D. B. Burt

Isoelectric focusing (IEF) was performed on soluble protein extracts from whole specimens of third-stage larval sealworm (Pseudoterranova decipiens) recovered from the musculature of three fish intermediate host species: Atlantic cod (Gadus morhua), sea raven (Hemitripterus americanus), and rainbow smelt (Osmerus mordax). The fish were collected at various sites in the Canadian Atlantic, and IEF revealed the occurrence of two "variants" within what has previously been considered a single, uniform species of P. decipiens in these waters. The larvae were characterized by the absence ("type I" L3's) or presence ("type II" L3's) of a sharp, dark-staining protein band with a mean pl of 6.46 pH units. Type I larvae were predominant at two sites sampled in the lower Bay of Fundy, while type II larvae were predominant at three sites sampled in the Gulf of St. Lawrence region.


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