Effect of temperature on viability and axial muscle development in embryos and yolk sac larvae of the Northeast Arctic cod ( Gadus morhua )

1998 ◽  
Vol 132 (4) ◽  
pp. 559-567 ◽  
Author(s):  
T. F. Galloway ◽  
E. Kjørsvik ◽  
H. Kryvi
Keyword(s):  
Gadus Morhua ◽  
Muscle Development ◽  
Yolk Sac ◽  
Effect Of Temperature ◽  
Arctic Cod ◽  
Axial Muscle

Accuracy and precision in stock separation of north-east Arctic and Norwegian coastal cod by otoliths - comparing readings, image analyses and a genetic method

2005 ◽  
Vol 56 (5) ◽  
pp. 753 ◽  
Author(s):  
Erik Berg ◽  
Tuula H. Sarvas ◽  
Alf Harbitz ◽  
Svein Erik Fevolden ◽  
Arnt Børre Salberg
Keyword(s):  
Visual Inspection ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Complete Separation ◽  
Arctic Cod ◽  
Genetic Method ◽  
North East ◽  
Accuracy And Precision ◽  
Growth Zones ◽  
The Difference

The distinction between north-east Arctic cod and Norwegian coastal cod, two major groups of Atlantic cod (Gadus morhua L.), has for many years been based on different distance and shape similarities between the two first translucent growth zones in the otoliths, subjectively decided by visual inspection in a binocular. To analyse the certainty of this technique, four independent readers have classified 263 cod otoliths in total from five different geographical areas. For three of the readers, between 82% and 89% of the classification results coincided with independent results based on genetic analyses. Further, 38 cod otoliths, where the readers were certain of the classification (21 north-east Arctic cod and 17 coastal cod) were classified by several image analysis methods. A complete separation was obtained by using the ratio of the circumferences of the two zones, providing a typical ratio of approximately 2 for coastal and 1.5 for north-east Arctic cod. The otolith method for separating the two types of cod has been considered adequately accurate in assessing the two stocks of cod. However, the method is sensitive to subjective interpretation, and action needs to be taken to minimise the difference in interpretation among otolith readers.

The Effects of External Salinity on the Drinking Rates of the Larvae of Herring, Plaice and Cod

1988 ◽  
Vol 138 (1) ◽  
pp. 1-15 ◽  
Author(s):  
P. TYTLER ◽  
J. H. BLAXTER
Keyword(s):  
Time Course ◽  
Gadus Morhua ◽  
Sea Water ◽  
Fluorescein Isothiocyanate ◽  
Yolk Sac ◽  
Clupea Harengus ◽  
Larval Stages ◽  
First Feeding ◽  
Fluorescein Isothiocyanate Dextran ◽  
External Salinity

Drinking responses to salinity change in the larvae of herring (Clupea harengus L.), plaice (Pleuronectes platessa L.) and cod (Gadus morhua L.) were measured from the time course of uptake of dextran labelled with tritium, following immersion in solutions of 32‰ and 16‰ sea water. The yolk sac and first feeding larval stages of all three species drink in both salinities. Furthermore, post-yolk sac stages appear to adjust their drinking rates to compensate for different salinities in a manner similar to that of the adults. Drinking rates in 32‰ sea water are approximately double those in 16‰. Mass-related drinking rates of larvae are higher than those in adults, but the differences do not match the differences in surface area to mass ratios, suggesting that larval skin is less permeable to water than is adult gill epithelium. Water absorption is indicated by the evidence of concentration of dextran in the gut. The estimates of drinking rates from tritiated dextran uptake are supported by epifluorescence microscopical measurements of the uptake of fluorescein isothiocyanate dextran.

scholarly journals External damage to trawl-caught northeast arctic cod (Gadus morhua): Effect of codend design

2019 ◽  
Vol 214 ◽  
pp. 136-147 ◽  
Author(s):  
Guro Møen Tveit ◽  
Manu Sistiaga ◽  
Bent Herrmann ◽  
Jesse Brinkhof
Keyword(s):  
Gadus Morhua ◽  
Arctic Cod ◽  
External Damage

The effect of temperature on the development of yolk-sac larvae of European hake (Merluccius merluccius L.) under laboratory conditions

2016 ◽  
Vol 48 (4) ◽  
pp. 1392-1405 ◽  
Author(s):  
Carlos Guevara-Fletcher ◽  
Paula Alvarez ◽  
Javier Sanchez ◽  
José Iglesias
Keyword(s):  
Yolk Sac ◽  
Effect Of Temperature ◽  
Merluccius Merluccius ◽  
Laboratory Conditions ◽  
European Hake

scholarly journals The effect of including length structure in yield-per-recruit estimates for northeast Arctic cod

2007 ◽  
Vol 64 (2) ◽  
pp. 357-368 ◽  
Author(s):  
Cecilie Kvamme ◽  
Bjarte Bogstad
Keyword(s):  
Alternative Model ◽  
Gadus Morhua ◽  
The Other ◽  
Natural Mortality ◽  
Fishing Mortality ◽  
Structured Model ◽  
Arctic Cod ◽  
Traditional Age ◽  
Size At Age ◽  
Yield Per Recruit

Abstract Kvamme, C., and Bogstad, B. 2007. The effect of including length structure in yield-per-recruit estimates for northeast Arctic cod. – ICES Journal of Marine Science, 64: 357–368. For northeast Arctic cod (Gadus morhua), traditional age-based estimates of yield per recruit (YPR) are compared with alternative, though comparable, YPR estimates calculated using an age–length-structured model. In the age–length-structured model, growth, fishing mortality, and natural mortality depend only on length, not on age. This model considers possible changes in size-at-age caused by, for example, a length-selective fishery, and therefore, by comparing the different YPR estimates, the importance of considering the stock's length structure can be evaluated. Length- and weight-at-age of stock and catches were influenced by exploitation pattern and pressure. Such changes are not considered in traditional estimates of YPR, for which weight-at-age is fixed and strictly speaking only representative for the current fishery. Consequently, traditional YPR estimates were somewhat higher than the age–length-based estimates for exploiting smaller fish than at present, and the other way round for exploiting larger fish. Both models indicated a gain in YPR for reducing just exploitation pressure (traditional YPR, 13%; alternative model, 20%) or both reducing exploitation pressure and postponing exploitation (traditional YPR, 23–31%; alternative model, 33–48%), compared with the current fishery.

Survival, activity and feeding ability of Baltic cod (Gadus morhua) yolk-sac larvae at different salinities

1994 ◽  
Vol 45 (3) ◽  
pp. 435-445 ◽  
Author(s):  
Anders Nissling ◽  
Per Solemdal ◽  
Mikael Svensson ◽  
Lars Westin
Keyword(s):  
Gadus Morhua ◽  
Yolk Sac ◽  
Baltic Cod
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