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

Swimming Endurance of Some Northwest Atlantic Fishes

1966 ◽  
Vol 23 (3) ◽  
pp. 341-347 ◽  
Author(s):  
F. W. H. Beamish
Keyword(s):  
Swimming Speed ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Winter Flounder ◽  
Pseudopleuronectes Americanus ◽  
Northwest Atlantic ◽  
Sea Raven ◽  
Longhorn Sculpin ◽  
Hemitripterus Americanus ◽  
Swimming Endurance

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.

Comparison of harbour seal diets in two inshore habitats of Atlantic Canada

1996 ◽  
Vol 74 (1) ◽  
pp. 125-135 ◽  
Author(s):  
W. D. Bowen ◽  
G. D. Harrison
Keyword(s):  
Gadus Morhua ◽  
Prey Species ◽  
Atlantic Cod ◽  
Atlantic Coast ◽  
Clupea Harengus ◽  
Harbour Seal ◽  
Bay Of Fundy ◽  
Alosa Pseudoharengus ◽  
Pseudopleuronectes Americanus ◽  
Capelin Mallotus Villosus

We studied the composition of harbour seal (Phoca vitulina) diets in two areas, the lower Bay of Fundy and along the northeastern coast of Nova Scotia, that differ in prey species diversity, bottom type, and physical oceanography. Prey remains were found in 250 of 470 harbour seal stomachs collected mainly from May to September between 1988 and 1992. Although 23 taxa were identified, four species, Atlantic herring (Clupea harengus), Atlantic cod (Gadus morhua), pollock (Pollachius virens), and short-finned squid (Illex illecebrosus), accounted for 84% of the estimated biomass of prey consumed in the two areas combined. Species, such as herring and squid, that dominated the diets in both habitats, also tended to be abundant in both habitats during the summer. Atlantic cod was the principal gadoid in the Bay of Fundy, whereas pollock was most important along the Atlantic coast. Differences in prey distribution and abundance appeared to account for differences in the contribution of the alewife (Alosa pseudoharengus), winter flounder (Pseudopleuronectes americanus), hake (Urophycis spp.), and capelin (Mallotus villosus) in the diet. Pronounced interannual variation in the species composition of diets was evident in both habitats. This variation was associated with broad-scale changes in prey abundance in some cases (e.g., squid and capelin) but not in others (e.g., Atlantic cod and pollock).

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.

Oocyte Maturation and Ovulation Induced in Hypophysectomized Winter Flounder (Pseudopleuronectes americanus) by Preparations from Pituitary Glands of American Plaice (Hippoglossoides platessoides)

1977 ◽  
Vol 34 (11) ◽  
pp. 2142-2150 ◽  
Author(s):  
C. M. Campbell ◽  
D. R. Idler
Keyword(s):  
Key Words ◽  
Oocyte Maturation ◽  
Winter Flounder ◽  
Pseudopleuronectes Americanus ◽  
Con A ◽  
Pituitary Glands ◽  
Hippoglossoides Platessoides

Hypophysectomized winter flounder (Pseudopleuronectes americanus) did not undergo spontaneous oocyte maturation, but the glycoprotein fraction of extracts of American plaice (Hippoglossoides platessoides) pituitaries induced maturation and ovulation. The nonglycoprotein fractions, previously shown to contain a vitellogenic factor, were less efficient than the glycoprotein fractions in the induction of maturation and ovulation. The activity of the nonglycoprotein fraction was further reduced by rechromatography on Con-A Sepharose, suggesting that its action on oocyte maturation and ovulation was due to contamination by the glycoprotein gonadotropin. Key words: hypophysectomy, gonadotropin, oocyte, maturation, ovulation, vitellogenesis, flounder, plaice, Pseudopleuronectes, Hippoglossoides

Infectivity of Trypanosoma murmanensis to leeches (Johanssonia sp.)

1977 ◽  
Vol 55 (10) ◽  
pp. 1698-1700 ◽  
Author(s):  
R. A. Khan
Keyword(s):  
Marine Fish ◽  
Gadus Morhua ◽  
Developmental Stages ◽  
Infected Fish ◽  
Winter Flounder ◽  
Pseudopleuronectes Americanus

Experiments were designed to test the infectivity of trypomastigotes of Trypanosoma murmanensis to leeches at intervals after metatrypomastigotes had initiated infections in marine fish. Infectivity was determined by the presence of developmental stages in recently emerged leeches (Johanssonia sp.) that had fed on experimentally infected fish. A total of 1235 leeches were used in this study. The results indicate that the three morphotypes can initiate infections in leeches. Moreover, some trypanosomes are infective at least 24 h after transmission (16 (67%) leeches became infected). Few leeches acquired infections after feeding on infected winter flounder (Pseudopleuronectes americanus) between 2 and 12 days and on a cod (Gadus morhua) 4–5 days, but all those which fed 7 through 93 day s on five species of marine teleosts became infected. Some of the leeches transmitted infections to uninfected cod. It is believed that the leeches which harboured no developmental stages might not have ingested trypanosomes.

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.

Feeding chronology and daily ration calculations for winter flounder (Pseudopleuronectes americanus), American plaice (Hippoglossoides platessoides), and ocean pout (Macrozoarces americanus) in Passamaquoddy Bay, New Brunswick

1987 ◽  
Vol 65 (3) ◽  
pp. 499-503 ◽  
Author(s):  
J. Stevenson Macdonald ◽  
Kenneth G. Waiwood
Keyword(s):  
Consumption Rate ◽  
Winter Flounder ◽  
Analysis Of Covariance ◽  
Fish Length ◽  
Benthic Fish ◽  
Daily Ration ◽  
Pseudopleuronectes Americanus ◽  
Gastric Evacuation ◽  
Passamaquoddy Bay ◽  
Hippoglossoides Platessoides

Feeding chronologies of three species of cohabiting benthic fish, winter flounder (Pseudopleuronectes americanus), ocean pout (Macrozoarces americanus), and American plaice (Hippoglossoides platessoides), are described. The volume of food eaten by each species at each of four collection times over 24 h was analysed using analysis of covariance (ANCOVA), with fish length as the covariate. Daily ration was estimated using a gastric evacuation model, incorporating mean stomach volumes at four subdaily intervals and independent evacuation rates for slower (bivalves) and faster digested prey (amphipods and polychaetes). Winter flounder, American plaice, and ocean pout were daylight feeders with American plaice feeding more heavily later in the day. Winter flounder had the highest consumption rate (1.77% body weight/day) followed by ocean pout (1.68%) and American plaice (1.28%). Estimates of daily and subdaily food consumption were compared with corresponding estimates based on prey-specific state of digestion indices. This study indicates that estimating total and individual prey consumption at subdaily intervals provides a useful tool in determining feeding chronology and draws attention to potential biases encountered when more traditional analyses are used.

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.

Changes in the Diet of Demersal Fish due to Eutrophication-Induced Hypoxia in the Kattegat, Sweden

1994 ◽  
Vol 51 (2) ◽  
pp. 321-336 ◽  
Author(s):  
Leif Pihl
Keyword(s):  
Fish Species ◽  
Gadus Morhua ◽  
Prey Species ◽  
Atlantic Cod ◽  
Benthic Communities ◽  
Demersal Fish ◽  
Organic Enrichment ◽  
Fish Diet ◽  
Dietary Shift ◽  
Term Change

The diets of five dominant bottom-feeding fish species, Atlantic cod (Gadus morhua), whiting (Merlangius merlangus), plaice (Pleuronectes platessa), dab (Limanda limanda), and American plaice (Hippoglossoides platessoides), were analysed during spring and autumn between May 1984 and April 1988 in the southeast Kattegat. A general long-term change in the diet of bottom-feeding fish in the Kattegat has taken place since the beginning of the century and, for some of the species, the feeding pattern was different from that in adjacent areas. The observed dietary shift appeared to be due to changes in species composition of benthic macrofauna. Prey species favored by increased organic enrichment were dominant in the diet. Several infaunal species increased in dietary importance during recent hypoxia. In contrast, during hypoxia, a reduction of epibenthic crustaceans was observed in the fish diet. This study emphasizes the potential effects of organic enrichment and hypoxia (due to eutrophication) on trophic interactions in marine benthic communities. Repeated stress from hypoxia might favor small-sized prey species with a short life cycle, which would in turn favor small-sized fishes. Thus, altered food resources and the direct effects of hypoxia might result in shift in dominance among demersal fish species.

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