Susceptibility of marine fish to trypanosomes

1977 ◽  
Vol 55 (8) ◽  
pp. 1235-1241 ◽  
Author(s):  
R. A. Khan
Keyword(s):  
Marine Fish ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Single Species ◽  
Marine Fish Species ◽  
Limanda Ferruginea ◽  
Spotted Wolffish ◽  
Host Origin ◽  
Morphology And Morphometry ◽  
Hippoglossoides Platessoides

Trypanosomes, some of similar morphology and morphometry, were observed in the blood of seven species of marine teleosts (Pleuronectiformes: American plaice (Hippoglossoides platessoides), yellowtail flounder (Limanda ferruginea), and grey sole (Glyptocephalus cynoglossus); Perciformes: Arctic eelpout (Lycodes reticulatus), spotted wolffish (Anarhichas minor), striped wolffish (A. lupus), and polka-dot seasnail (Liparis cyclostigma)) collected off coastal Newfoundland, Canada. Experiments to ascertain specificity or susceptibility of the trypanosomes were initiated using leeches as vectors. Trypanosomes from pleuronectiform and perciform fish were equally infective to taxonomically related and unrelated species, including a gadiform fish, the Atlantic cod (Gadus morhua). Moreover, Trypanosoma murmanensis of the cod was transmitted to pleuronectiform, perciform, anguilliform, and gadiform fish. No marine fish species tested was insusceptible to trypanosomes isolated from the different hosts. In all fish, there was a progessive increase in size with time, reaching the maximum by 60 days postinfection. No striking differences in morphology or morphometry were apparent among the trypanosomes in recipient fish regardless of host origin. The opinion is expressed that the trypanosomes of these marine fish, which have overlapping geographical distributions, belong to a single species, referrable to T. murmanensis Nikitin, 1927.

scholarly journals Marine fish haematozoa from Newfoundland waters

1972 ◽  
Vol 50 (5) ◽  
pp. 543-554 ◽  
Author(s):  
Bernard K. F. So
Keyword(s):  
Marine Fish ◽  
Gadus Morhua ◽  
Melanogrammus Aeglefinus ◽  
Potential Vector ◽  
Type Host ◽  
Limanda Ferruginea ◽  
New Hosts ◽  
Myoxocephalus Scorpius ◽  
Raja Radiata ◽  
Hippoglossoides Platessoides

Of 797 fish of 28 species, 159 of 12 species yielded blood protozoa. Trypanosoma rajae is recorded from Raja radiata. Undetermined trypanosomes are reported from Glyptocephalus cynoglossus and Gadus morhua, respectively. Haemogregarina myoxocephali is listed from the type host, Myoxocephalus octodecemspinosus. The occurrence of haemogregarine sporozoites (perhaps of this species) in the gut of a piscicolid leech (Malmiana nuda) from Myoxocephalus scorpius represents the first discovery of a potential vector of any fish haemogregarine. New hosts are listed for Haemogregarina delagei and H. platessae. A babesioid Haemohormidium terraenovae n. sp. is described from six hosts: Ammodytes americanus, Urophycis tenuis, Melanogrammus aeglefinus, Limanda ferruginea, Glyptocephalus cynoglossus, and Hippoglossoides platessoides; and another, Haemohormidium beckeri n. s p., from Myoxocephalus octodecemspinosus.

How to validate a length-based model of single-species fish stock dynamics

2006 ◽  
Vol 63 (11) ◽  
pp. 2531-2542 ◽  
Author(s):  
Kasper Kristensen ◽  
Peter Lewy ◽  
Jan E Beyer
Keyword(s):  
Survey Data ◽  
Gadus Morhua ◽  
Negative Binomial ◽  
Atlantic Cod ◽  
Population Level ◽  
Single Species ◽  
Model Complexity ◽  
Fish Stock ◽  
Statistical Hypotheses ◽  
The Baltic

This paper validates a new length-based model of the dynamics of fish stocks or crustaceans by hierarchically testing statistical hypotheses and thereby investigating model complexity. The approach is based entirely on scientific survey data and on determination of the statistical distributions of the number of fish caught per haul in each length class. In our example, the negative binomial distribution is statistically accepted and linked to the population level through the new length-based model. The model is derived from the characteristics of continuous recruitment, individually based growth, and continuous, length-dependent mortality rates. Continuous recruitment with annually varying recruitment peaks and individually based growth was crucial for obtaining a model that could be statistically accepted. Natural mortality was estimated as well by the model. The model was applied to survey data for Atlantic cod (Gadus morhua) in the Baltic. Its simple generic nature, as well as the validation procedure, is useful in studying and understanding life history and stock dynamics.

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.

Seasonal variation in the habitat associations of Atlantic cod (Gadus morhua) and American plaice (Hippoglossoides platessoides) from the southern Gulf of St. Lawrence

1998 ◽  
Vol 55 (12) ◽  
pp. 2548-2561 ◽  
Author(s):  
D P Swain ◽  
G A Chouinard ◽  
R Morin ◽  
K F Drinkwater
Keyword(s):  
Seasonal Variation ◽  
Habitat Selection ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Statistical Significance ◽  
Habitat Associations ◽  
Practical Implications ◽  
Hippoglossoides Platessoides ◽  
Trawl Surveys ◽  
Selection Of

We compared habitat associations of southern Gulf of St. Lawrence Atlantic cod (Gadus morhua) and American plaice (Hippoglossoides platessoides) between the summer feeding season on the Magdalen Shallows and the overwintering period in the Cabot Strait. Data were from bottom trawl surveys conducted in September 1993, 1994, and 1995 and January 1994, 1995, and 1996. Both species occupied much deeper, warmer water in winter than in summer. The effect of cod age on temperature distribution reversed between the two seasons, with younger cod occupying warmer water than older cod in summer and colder water in winter. Selection of both depth and temperature by cod tended to be more significant in September than in January. The reduced statistical significance of habitat selection by cod in winter was associated with a more aggregated distribution in this season. The contrast between seasons in habitat associations was particularly strong for plaice. The median habitats occupied by plaice were 58-67 m and -0.1 to 0.3°C in September and 374-426 m and 5.2-5.4°C in January. Habitat selection by plaice was significant in both seasons, but significance tended to be greater in January. Degree of aggregation in plaice distribution was similar between the two seasons. Female plaice occupied significantly warmer water than males in September but not in January. The ecological and practical implications of this striking seasonal variation in habitat associations are discussed.

Protein Instability in Minced Flesh from Fillets and Frames of Several Commercial Atlantic Fishes During Storage at −5 C

1975 ◽  
Vol 32 (6) ◽  
pp. 775-783 ◽  
Author(s):  
J. R. Dingle ◽  
J. A. Hines
Keyword(s):  
Gadus Morhua ◽  
Atlantic Cod ◽  
Protein Solubility ◽  
Kidney Tissue ◽  
Rapid Loss ◽  
Atlantic Mackerel ◽  
Trimethylamine Oxide ◽  
Minced Fish ◽  
Protein Instability ◽  
Hippoglossoides Platessoides

Minced flesh of Atlantic cod (Gadus morhua) and pollock (Pollachius virens), recovered by means of meat-separator machines from frames left after filleting operations, suffered a rapid loss of protein solubility during storage at −5 C. This was due to the presence of kidney tissue which caused the formation of dimethylamine and formaldehyde from the trimethylamine oxide of the muscle. The minced flesh of witch flounder (Glyptocephalus cynoglossus), American plaice (Hippoglossoides platessoides), and Atlantic mackerel (Scomber scombrus) was relatively stable when mixed with homogenates of their own kidney tissue, but cod kidney caused the same changes in gray sole as it did in minced cod flesh. The exclusion of gadoid kidney and blood from minced fish preparations is recommended.

In what direction should the fishing mortality target change when natural mortality increases within an assessment?

2016 ◽  
Vol 73 (3) ◽  
pp. 349-357 ◽  
Author(s):  
Christopher M. Legault ◽  
Michael C. Palmer
Keyword(s):  
Mortality Rate ◽  
Empirical Evidence ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Stock Assessment ◽  
Total Mortality ◽  
Natural Mortality ◽  
Fishing Mortality ◽  
Limanda Ferruginea ◽  
Trade Offs

Traditionally, the natural mortality rate (M) in a stock assessment is assumed to be constant. When M increases within an assessment, the question arises how to change the fishing mortality rate target (FTarget). Per recruit considerations lead to an increase in FTarget, while limiting total mortality leads to a decrease in FTarget. Application of either approach can result in nonsensical results. Short-term gains in yield associated with high FTarget values should be considered in light of potential losses in future yield if the high total mortality rate leads to a decrease in recruitment. Examples using yellowtail flounder (Limanda ferruginea) and Atlantic cod (Gadus morhua) are used to demonstrate that FTarget can change when M increases within an assessment and to illustrate the consequences of different FTarget values. When a change in M within an assessment is contemplated, first consider the amount and strength of empirical evidence to support the change. When the empirical evidence is not strong, we recommend using a constant M. If strong empirical evidence exists, we recommend estimating FTarget for a range of stock–recruitment relationships and evaluating the trade-offs between risk of overfishing and forgone yield.

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