scholarly journals Comparative Recoveries of Spaghetti Tags and Disc Tags on Atlantic Cod (Gadus morhua) and American Plaice (Hippoglossoides platessoides)

1991 ◽  
Vol 11 ◽  
pp. 39-42 ◽  
Author(s):  
G M Fowler ◽  
W T Stobo
Keyword(s):  
Gadus Morhua ◽  
Atlantic Cod ◽  
Hippoglossoides Platessoides

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.

Seasonal and diel variations of various blood parameters in Atlantic cod (Gadus morhua) and American plaice (Hippoglossoides platessoides)

1993 ◽  
Vol 71 (3) ◽  
pp. 611-618 ◽  
Author(s):  
Céline Audet ◽  
Michel Besner ◽  
Jean Munro ◽  
Jean-Denis Dutil
Keyword(s):  
Gadus Morhua ◽  
Atlantic Cod ◽  
Plasma Osmolality ◽  
Blood Parameters ◽  
Time Of Day ◽  
Seasonal Effect ◽  
Lawrence Estuary ◽  
Blood Hemoglobin ◽  
Diel Variations ◽  
Hippoglossoides Platessoides

Seasonal and diel variations of different blood variables were studied in Atlantic cod (Gadus morhua) and American plaice (Hippoglossoides platessoides) subjected to natural fluctuations of salinity and temperature in the St. Lawrence estuary. Significant seasonal fluctuations were found for all the parameters measured (plasma osmolality, Na+, Cl−, K+, glucose, Cortisol, and blood hemoglobin and hematocrit). In cod, the seasonal effect on blood hemoglobin was only detected through its interaction with time of day. In this species, all parameters also varied on an hourly basis, although these changes only represented a small proportion of the variance explained by the statistical model. In plaice, only plasma osmotic composition and blood hematocrit did not show diel variations, while the hour effect was difficult to characterize. In general, though our results indicate that both species acclimated to test conditions, American plaice seemed to cope less efficiently than Atlantic cod with winter conditions. In this respect, the Atlantic cod represents a better candidate for coastal aquaculture in this area.

Arsenic Concentrations in Some Coexisting Marine Organisms from Newfoundland and Labrador

1976 ◽  
Vol 33 (6) ◽  
pp. 1388-1393 ◽  
Author(s):  
Victor S. Kennedy
Keyword(s):  
Newfoundland And Labrador ◽  
Gadus Morhua ◽  
Carapace Length ◽  
Sea Water ◽  
Atlantic Cod ◽  
Negative Relationship ◽  
Inorganic Arsenic ◽  
Fish Muscle ◽  
Reinhardtius Hippoglossoides ◽  
Hippoglossoides Platessoides

Inorganic arsenic concentrations in sea water and mud, and total arsenic concentrations in bodies of shrimp, zooplankton, and fish from northern Newfoundland and southern Labrador were measured. There was a positive relationship between concentration and carapace length in Pandalus borealis and P. montagui and a negative relationship in Eualus macilentus. There was no relationship between concentrations in shrimp eggs and carapace length. Arsenic concentrations in zooplankton and fish muscle were relatively low compared with the shrimp species; amphipods contained more arsenic than copepods or euphausiids, and American plaice (Hippoglossoides platessoides) more than redfish (Sebastes marinus), turbot (Reinhardtius hippoglossoides), and Atlantic cod (Gadus morhua). There was no evidence of increasing arsenic concentrations through successively higher levels of the food chain.

Rates of Digestion of Different Prey in Atlantic Cod (Gadus morhua), Ocean Pout (Macrozoarces americanus), Winter Flounder (Pseudopleuronectes americanus), and American Plaice (Hippoglossoides platessoides)

1982 ◽  
Vol 39 (5) ◽  
pp. 651-659 ◽  
Author(s):  
J. Stevenson Macdonald ◽  
Kenneth G. Waiwood ◽  
Roger H. Green
Keyword(s):  
Goodness Of Fit ◽  
Gadus Morhua ◽  
Prey Species ◽  
Atlantic Cod ◽  
Graphical Analysis ◽  
Winter Flounder ◽  
Pseudopleuronectes Americanus ◽  
Evaluation Procedures ◽  
Visual Index ◽  
Hippoglossoides Platessoides

Stomachs of ocean pout (Macrozoarces americanus), Atlantic cod (Gadus morhua), winter flounder (Pseudopleuronectes americanus), and American plaice (Hippoglossoides platessoides) were removed and dissected 5, 12, 20, and 30 h after the fish had fed voluntarily to test the evacuation rates of three different prey species. Two evaluation procedures were used: a visual index of recognizabiiity, and a graphical analysis of percent of each prey recovered versus time since feeding. Three decay models were tested for goodness of fit to the evacuation data. The polychaete worms were the first to become unrecognizable, followed by amphipods. These species showed significantly different rates of evacuation when compared with the bivalves which were recognizable for the longest time. The exponential decay curve gave the best overall fit to the data. However, a linear model gave a good or better fit to the decay rate of the bivalve. The evacuation rates of different prey should be considered in estimating daily rations of fish in their environment.Key words: digestion, stomach content, food organism, Yoldia sapotilla, Tmetonyx cicada, Nephtys incisa

Geographical variations in abundance of larval anisakine nematodes in Atlantic cod (Gadus morhua) and American plaice (Hippoglossoides platessoides) from the Gulf of St. Lawrence

1995 ◽  
Vol 52 (S1) ◽  
pp. 105-115 ◽  
Author(s):  
France Boily ◽  
David J. Marcogliese
Keyword(s):  
Nova Scotia ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Temporal Variations ◽  
Anisakis Simplex ◽  
Geographical Variations ◽  
Pseudoterranova Decipiens ◽  
Hippoglossoides Platessoides

Atlantic cod (Gadus morhua) and American plaice (Hippoglossoides platessoides) collected from various sites in the Gulf of St. Lawrence (NAFO divisions 4RST) were examined for larval anisakine nematodes in 1990 and 1992. Sealworm larvae (Pseudoterranova decipiens) were more abundant in southern Gulf (4T) than in northern Gulf (4RS) cod and plaice. The heaviest sealworm infections occurred in fish from St. Georges Bay, Nova Scotia. Abundance of P. decipiens in cod from St. Georges Bay was significantly lower in 1992 than in 1990. Anisakis simplex and Contracaecinea (Contracaecum/Phocascaris spp.) were most abundant in cod from the northern Gulf. American plaice were not heavily infected with A. simplex or Contracaecinea. Geographical and temporal variations in abundance of larval anisakine nematodes in fish may reflect distribution and abundance of the phocid and cetacean definitive hosts and variations in water temperatures.

Sex-specific temperature distribution of American plaice (Hippoglossoides platessoides) and its relation to age and abundance

1997 ◽  
Vol 54 (5) ◽  
pp. 1077-1087 ◽  
Author(s):  
D P Swain
Keyword(s):  
Temperature Distribution ◽  
Gadus Morhua ◽  
Annual Variation ◽  
Atlantic Cod ◽  
Cold Temperatures ◽  
Fitness Benefits ◽  
Specific Temperature ◽  
The Difference ◽  
Using Data ◽  
Hippoglossoides Platessoides

I examined variation in the temperature distribution of American plaice (Hippoglossoides platessoides) in the southern Gulf of St. Lawrence using data from bottom trawl surveys conducted each September since 1971. Plaice tended to select cold temperatures relative to those available. Temperature distribution was unrelated to age over the range 3-12+ years. Females tended to occupy warmer water than males, although the extent of this difference between the sexes varied among years. Annual variation in plaice temperature distribution was positively correlated with variation in the temperatures available. After accounting for annual variation in available temperatures, female temperature distribution was density independent but males tended to occupy colder water at higher levels of abundance. The median temperature occupied by both sexes tended to be warmer at higher levels of abundance of Atlantic cod (Gadus morhua), a competitor of plaice. The difference between the sexes in temperature distribution increased as cod abundance decreased or as plaice abundance increased (depending on the measure of temperature distribution used). The observed difference between the sexes in temperature distribution and its density dependence may reflect differences in foraging rate associated with differences between the sexes in the fitness benefits of growth.

Effects of release parameters on recovery rates of tagged groundfish species

1999 ◽  
Vol 56 (10) ◽  
pp. 1732-1751 ◽  
Author(s):  
G M Fowler ◽  
W T Stobo
Keyword(s):  
Gadus Morhua ◽  
Atlantic Cod ◽  
Melanogrammus Aeglefinus ◽  
Fish Length ◽  
Significant Determinant ◽  
Coastal Regions ◽  
Recovery Rates ◽  
Haddock Melanogrammus Aeglefinus ◽  
Hippoglossoides Platessoides ◽  
Over Time

A compilation of groundfish mark-recapture studies conducted in the Northwest Atlantic from 1953 to 1985 was examined by analysis of deviance to determine the effects of release parameters on subsequent recoveries of Atlantic cod (Gadus morhua), haddock (Melanogrammus aeglefinus), pollock (Pollachius virens), and American plaice (Hippoglossoides platessoides). Fish length was a major determinant of recoveries for all four species, with recovery rates generally increasing with increasing fish length. Depth of capture was a significant determinant of recoveries for cod and haddock, with recovery rates decreasing as depth increased. Year of release was a significant determinant for all four species, with recovery rates declining in recent years. Declines in recovery rates of cod, haddock, and pollock occurred during certain months or seasons. Recovery rates decreased where fish were tagged in areas most distant from inhabited coastal regions, but the interpretation of this effect is complicated by changes in the fisheries over time between areas. Recovery rates also decreased with increasing catch size and varied between different tag types and capture methods. The results should prove useful in the design of tagging protocols and analysis of recovery data.

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.

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