Gadus morhua

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Axel Temming - One of the best experts on this subject based on the ideXlab platform.

  • explaining diet composition of north sea cod Gadus morhua prey size preference vs prey availability
    Canadian Journal of Fisheries and Aquatic Sciences, 2003
    Co-Authors: Jens Floeter, Axel Temming
    Abstract:

    The nature and significance of size preference for fish prey in the diet selection of North Sea cod (Gadus morhua L.) was analysed. The analysis combined information on size-specific abundance derived from bottom trawl surveys with prey size frequencies in cod stomachs from the International North Sea Stomach Database. To estimate the abundance of all potential fish prey in the sea, a length-based number spectrum was calculated, corrected for gear efficiency by the application of a species-specific correction factor, and weighted by local predator abundance to take the spatial–temporal overlap between cod and its prey into consideration. A prey size preference model for cod feeding on fish is presented. Results showed that the preferred predator-to-prey weight ratio is an exponentially increasing function of predator size and an exponentially decreasing function of the slope of the number spectrum. More than 75% of fish found in the stomachs of North Sea cod originated from the least preferred quartile of...

  • explaining diet composition of north sea cod Gadus morhua prey size preference vs prey availability
    Canadian Journal of Fisheries and Aquatic Sciences, 2003
    Co-Authors: Jens Floeter, Axel Temming
    Abstract:

    The nature and significance of size preference for fish prey in the diet selection of North Sea cod (Gadus morhua L.) was analysed. The analysis combined information on size-specific abundance deri...

George A Rose - One of the best experts on this subject based on the ideXlab platform.

  • atlantic cod Gadus morhua feed during spawning off newfoundland and labrador
    Ices Journal of Marine Science, 2012
    Co-Authors: Kyle J Krumsick, George A Rose
    Abstract:

    We test a current assumption that Atlantic cod (Gadus morhua) off Newfoundland and Labrador, Canada, do not feed during the protracted spawning season (March–September). Stomach contents were analysed from 10 473 cod from four Northwest Atlantic Fisheries Organization regions (2J, 3K, 3L, and 3Ps) over 9 years from which gonads were also analysed to determine sex and maturity status. Adult cod in spawning condition did feed in all regions, usually at rates equivalent to or even greater than non-spawning fish and juveniles. Both sexes fed during spawning, though females consumed lesser amounts. Regional differences were evident. The total fullness index was greater in the northern (2J) than the southern (3Ps) region, with no consistent differences between spawners and non-spawners. The most southerly region (3Ps) exhibited the greatest prey diversity, the northern region (2J) the least. Shrimp was the major diet item in the northern regions. Capelin, zooplankton, crab, and other fish increased in importance to the south. Differences in prey items between non-spawning and spawning individuals of both sexes were possibly related to spawning behaviour. Models using consumption rates should not assume that cod do not feed during the protracted spawning season in these waters.

  • migration route familiarity and homing of transplanted atlantic cod Gadus morhua
    Fisheries Research, 2005
    Co-Authors: Matthew J S Windle, George A Rose
    Abstract:

    Abstract To investigate migration route familiarity and homing success of Atlantic cod ( Gadus morhua L.), acoustically tagged spawning cod caught at the Bar Haven spawning ground, Placentia Bay, Newfoundland, were transplanted 21 km along their migratory pathway and 21 km in the opposing direction. A control group was released where caught. Transplanted groups included fish of both sexes and two size classes (58–60 cm and >70 cm). Tagged cod were then relocated using biotelemetry. All 16 control fishes were relocated at Bar Haven. Twelve of 32 transplanted fishes had known fates (seven returned to Bar Haven, the earliest 12 days after release, and five died). Significantly more cod returned from the migratory pathway (adjusted rate of 51%) compared to cod released outside of this area (13%). Small males showed the highest same year homing rates (88%): large females the poorest (0%). After one year at large, significantly more cod released in the migratory pathway returned to Bar Haven during the spawning season, suggesting that cod may repeat the migratory behaviour of previous years.

  • reconciling overfishing and climate change with stock dynamics of atlantic cod Gadus morhua over 500 years
    Canadian Journal of Fisheries and Aquatic Sciences, 2004
    Co-Authors: George A Rose
    Abstract:

    To examine overfishing and climate effects on depleted cod (Gadus morhua) stocks, a surplus production model based on reconstructions of cod catch in Newfoundland was used to describe biomass dynam...

  • reconciling overfishing and climate change with stock dynamics of atlantic cod Gadus morhua over 500 years
    Canadian Journal of Fisheries and Aquatic Sciences, 2004
    Co-Authors: George A Rose
    Abstract:

    To examine overfishing and climate effects on depleted cod (Gadus morhua) stocks, a surplus production model based on reconstructions of cod catch in Newfoundland was used to describe biomass dynamics from 1505 to 2004. Productivity parameters r (population growth rate) and K (carrying capacity) were assigned by fitting model to survey biomass. Assumptions of fishery-only influences inferring constant, random, or depensatory parameters fared poorly (did not mimic history), as did climate influences indexed by tree ring growth. However, a model using both climate and depensation fared well, mimicking much documented history of Newfoundland cod, including declines during the Little Ice Age (mid- to late 19th century) and the stock collapses of the late 20th century, with a good fit to recent scientific surveys (r2 = 0.80). This model suggests temporal differentiation between fishing and climate effects, including (i) declines during the Little Ice Age (1800–1880) caused by lower productivity, (ii) collapses...

  • Distribution shifts and overfishing the northern cod (Gadus morhua): a view from the ocean
    Canadian Journal of Fisheries and Aquatic Sciences, 2000
    Co-Authors: George A Rose, Brad Deyoung, D W Kulka, S. V. Goddard, Garth L. Fletcher
    Abstract:

    Research on northern cod (Gadus morhua) from 1983 to 1994 indicated that a southward shift in distribution in the early 1990s was real and not an artifact of sequentially fishing down local populat...

Jens Floeter - One of the best experts on this subject based on the ideXlab platform.

  • explaining diet composition of north sea cod Gadus morhua prey size preference vs prey availability
    Canadian Journal of Fisheries and Aquatic Sciences, 2003
    Co-Authors: Jens Floeter, Axel Temming
    Abstract:

    The nature and significance of size preference for fish prey in the diet selection of North Sea cod (Gadus morhua L.) was analysed. The analysis combined information on size-specific abundance derived from bottom trawl surveys with prey size frequencies in cod stomachs from the International North Sea Stomach Database. To estimate the abundance of all potential fish prey in the sea, a length-based number spectrum was calculated, corrected for gear efficiency by the application of a species-specific correction factor, and weighted by local predator abundance to take the spatial–temporal overlap between cod and its prey into consideration. A prey size preference model for cod feeding on fish is presented. Results showed that the preferred predator-to-prey weight ratio is an exponentially increasing function of predator size and an exponentially decreasing function of the slope of the number spectrum. More than 75% of fish found in the stomachs of North Sea cod originated from the least preferred quartile of...

  • explaining diet composition of north sea cod Gadus morhua prey size preference vs prey availability
    Canadian Journal of Fisheries and Aquatic Sciences, 2003
    Co-Authors: Jens Floeter, Axel Temming
    Abstract:

    The nature and significance of size preference for fish prey in the diet selection of North Sea cod (Gadus morhua L.) was analysed. The analysis combined information on size-specific abundance deri...

Vera Lund - One of the best experts on this subject based on the ideXlab platform.

  • atypical furunculosis vaccines for atlantic cod Gadus morhua vaccine efficacy and antibody responses
    Vaccine, 2008
    Co-Authors: Vera Lund, Helene Mikkelsen, Kjersti Gravningen, Jan Arne Arnesen, Laura L Brown, Merete Bjorgan Schroder
    Abstract:

    Atypical furunculosis caused by atypical Aeromonas salmonicida, is an emerging problem in farming of Atlantic cod (Gadus morhua) in Norway, and vaccines are needed. Atypical A. salmonicida comprises a heterogeneous group of bacteria differing in surface antigens such as the A-layer protein and lipopolysaccharides (LPS). Except for one of the experimental oil-adjuvanted whole cell vaccines based on various isolates they all resulted in moderate protection. No clear correlation between vaccine efficacies and the A-protein group or LPS type of the vaccine isolates was revealed, while a correlation between efficacy and the presence of cross-reacting LPS-specific antibodies is indicated.

  • early vaccination and protection of atlantic cod Gadus morhua l juveniles against classical vibriosis
    Aquaculture, 2006
    Co-Authors: Merete Bjorgan Schroder, Helene Mikkelsen, Susanna Bordal, Kjersti Gravningen, Vera Lund
    Abstract:

    Abstract The effect of vaccinating Atlantic cod ( Gadus morhua L.) juveniles weighing from 1 to 20 g with a commercial vibriosis vaccine (ALPHA MARINE™ Vibrio, PHARMAQ AS) was determined by bath challenge with Vibrio anguillarum serotype O2b. Bath vaccination of cod juveniles of 1 g resulted in a poor protection when challenged 6 weeks later (RPS   75) compared to 1.7 g (RPS   76), that was comparable to the protection obtained 17 weeks post dip or i.p. vaccination at 20 g (RPS > 74).

  • vibriosis and atypical furunculosis vaccines efficacy specificity and side effects in atlantic cod Gadus morhua l
    Aquaculture, 2004
    Co-Authors: Helene Mikkelsen, Merete Bjorgan Schroder, Vera Lund
    Abstract:

    Abstract Atlantic cod, Gadus morhua L., vaccinated by injection with vaccines containing Vibrio anguillarum serotype O2 or atypical Aeromonas salmonicida bacterin, alone or with oil adjuvant, was highly protected against homologous challenge (relative percent survival [RPS]>94 and >77, respectively). Furthermore, the A. salmonicida bacterin also elicited significant protection against bath challenge with V. anguillarum (RPS>30). Oil adjuvant appeared to be unnecessary for obtaining short-term protection in cod against vibriosis and furunculosis. Neither the oil-adjuvanted vaccine nor the bacterin resulted in significantly reduced weight gain 12 weeks postvaccination, but intra-abdominal adhesions were observed in fish injected with oil-adjuvanted vaccines.

Merete Bjorgan Schroder - One of the best experts on this subject based on the ideXlab platform.

  • atypical furunculosis vaccines for atlantic cod Gadus morhua vaccine efficacy and antibody responses
    Vaccine, 2008
    Co-Authors: Vera Lund, Helene Mikkelsen, Kjersti Gravningen, Jan Arne Arnesen, Laura L Brown, Merete Bjorgan Schroder
    Abstract:

    Atypical furunculosis caused by atypical Aeromonas salmonicida, is an emerging problem in farming of Atlantic cod (Gadus morhua) in Norway, and vaccines are needed. Atypical A. salmonicida comprises a heterogeneous group of bacteria differing in surface antigens such as the A-layer protein and lipopolysaccharides (LPS). Except for one of the experimental oil-adjuvanted whole cell vaccines based on various isolates they all resulted in moderate protection. No clear correlation between vaccine efficacies and the A-protein group or LPS type of the vaccine isolates was revealed, while a correlation between efficacy and the presence of cross-reacting LPS-specific antibodies is indicated.

  • viral and bacterial diseases of atlantic cod Gadus morhua their prophylaxis and treatment a review
    Diseases of Aquatic Organisms, 2006
    Co-Authors: Ole Bent Samuelsen, Trond O Jorgensen, Merete Bjorgan Schroder, Audun Helge Nerland, Terje Svasand, Oivind Bergh
    Abstract:

    This review summarises the state of knowledge of both viral and bacterial diseases of Atlantic cod Gadus morhua, and their diagnosis, prophylaxis and treatment. The most important losses have been at the larval and juvenile stages, and vibriosis has long been the most important bacterial disease in cod, with Listonella (Vibrio) anguillarum dominant among pathogenic isolates. Vaccination of cod against pathogens such as L. anguillarum and Aeromonas salmonicida clearly demonstrates that the cod immune system possesses an effective memory and appropriate mecha- nisms sufficient for protection, at least against some diseases. Well-known viruses such as the nodavirus that causes viral encephalopathy and retinopathy (VER), infectious pancreatic necrosis virus (IPNV) and viral haemorrhagic septicaemia virus (VHSV) have been isolated from Atlantic cod and can be a potential problem under intensive rearing conditions. No commercial vaccines against nodavirus are currently available, whereas vaccines against IPNV infections based upon inactivated virus as well as IPNV recombinant antigens are available. A number of investigations of the pharma- cokinetic properties of antibacterial agents in cod and their efficacy in treating bacterial infections have been reviewed.

  • early vaccination and protection of atlantic cod Gadus morhua l juveniles against classical vibriosis
    Aquaculture, 2006
    Co-Authors: Merete Bjorgan Schroder, Helene Mikkelsen, Susanna Bordal, Kjersti Gravningen, Vera Lund
    Abstract:

    Abstract The effect of vaccinating Atlantic cod ( Gadus morhua L.) juveniles weighing from 1 to 20 g with a commercial vibriosis vaccine (ALPHA MARINE™ Vibrio, PHARMAQ AS) was determined by bath challenge with Vibrio anguillarum serotype O2b. Bath vaccination of cod juveniles of 1 g resulted in a poor protection when challenged 6 weeks later (RPS   75) compared to 1.7 g (RPS   76), that was comparable to the protection obtained 17 weeks post dip or i.p. vaccination at 20 g (RPS > 74).

  • vibriosis and atypical furunculosis vaccines efficacy specificity and side effects in atlantic cod Gadus morhua l
    Aquaculture, 2004
    Co-Authors: Helene Mikkelsen, Merete Bjorgan Schroder, Vera Lund
    Abstract:

    Abstract Atlantic cod, Gadus morhua L., vaccinated by injection with vaccines containing Vibrio anguillarum serotype O2 or atypical Aeromonas salmonicida bacterin, alone or with oil adjuvant, was highly protected against homologous challenge (relative percent survival [RPS]>94 and >77, respectively). Furthermore, the A. salmonicida bacterin also elicited significant protection against bath challenge with V. anguillarum (RPS>30). Oil adjuvant appeared to be unnecessary for obtaining short-term protection in cod against vibriosis and furunculosis. Neither the oil-adjuvanted vaccine nor the bacterin resulted in significantly reduced weight gain 12 weeks postvaccination, but intra-abdominal adhesions were observed in fish injected with oil-adjuvanted vaccines.

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