scholarly journals Description and Comparison of Eggs and Yolk Sac Larvae of Greenland Cod (Gadus ogac), Atlantic Cod (Gadus morhua) and Arctic Cod(Boreogadus saida) from West Greenland Waters

1994 ◽  
Vol 16 ◽  
pp. 19-32 ◽  
Author(s):  
O G N Andersen ◽  
J R Nielsen ◽  
E L B Smidt
Keyword(s):  
Gadus Morhua ◽  
Atlantic Cod ◽  
Yolk Sac ◽  
Boreogadus Saida ◽  
Arctic Cod ◽  
West Greenland

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.

scholarly journals New encounters in Arctic waters: a comparison of metabolism and performance of polar cod (Boreogadus saida) and Atlantic cod (Gadus morhua) under ocean acidification and warming

Polar Biology ◽  
2016 ◽  
Vol 39 (6) ◽  
pp. 1137-1153 ◽  
Author(s):  
Kristina Lore Kunz ◽  
Stephan Frickenhaus ◽  
Silvia Hardenberg ◽  
Torild Johansen ◽  
Elettra Leo ◽  
...  
Keyword(s):  
Ocean Acidification ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Polar Cod ◽  
Boreogadus Saida ◽  
Polar Cod Boreogadus Saida ◽  
And Performance

Diet of harp seals (Phoca groenlandica) in nearshore waters of the northwest Atlantic during 1990 – 1993

1995 ◽  
Vol 73 (10) ◽  
pp. 1805-1818 ◽  
Author(s):  
John W. Lawson ◽  
Garry B. Stenson ◽  
Dave G. McKinnon
Keyword(s):  
Gadus Morhua ◽  
Atlantic Cod ◽  
Stomach Contents ◽  
Clupea Harengus ◽  
Relative Importance ◽  
Northwest Atlantic ◽  
Arctic Cod ◽  
Diet Diversity ◽  
Phoca Groenlandica ◽  
Capelin Mallotus Villosus

The nearshore diet of northwest Atlantic harp seals (Phoca groenlandica) was determined by reconstructing the contents of 1167 prey-containing stomachs (78.3% of 1490) collected from 1990 to 1993. Although harp seals consumed at least 62 species, 6 accounted for most of the mass consumed and their relative importance varied by area. Based on percent wet mass, sculpins (Cottidae) and Arctic cod (Boreogadus saida) were the main components of the diet of older seals (> 1 year old) off Labrador, whereas Arctic cod and Atlantic herring (Clupea harengus) were the main prey of seals from northeastern Newfoundland. A more diverse diet was observed in seals taken off the west coast of Newfoundland, where capelin (Mallotus villosus), herring, Atlantic cod (Gadus morhua), redfish (Sebastes spp.), and Arctic cod were the main species. Redfish and Atlantic cod were important to seals along the south coast of Newfoundland. Eighty percent of fish consumed were less than 18 cm long, smaller than those taken by commercial fisheries. Pups (less than 1 year old) consumed fewer and smaller prey of a less varied assortment. Annual and seasonal variation in the diets was observed in the collection from northeastern Newfoundland. Arctic cod was the major prey consumed throughout the year by seals of all ages, although the relative importance of herring, capelin, and squid (Teuthoidea) increased during the summer. Invertebrates and capelin made up a greater proportion of the diet in 1992, owing to a decline in consumption of Arctic cod. This finding was associated with a decrease in the mass of stomach contents. Diet diversity did not change significantly over the study period.

scholarly journals Morphology, Transcriptomics and In Vitro Model of Skin from Polar Cod (Boreogadus Saida) and Atlantic Cod (Gadus Morhua)

Fishes ◽  
2020 ◽  
Vol 5 (4) ◽  
pp. 34
Author(s):  
Elisabeth Ytteborg ◽  
Øyvind Johannes Hansen ◽  
Vibeke Høst ◽  
Sergey Afanasyev ◽  
Ireen Vieweg ◽  
...  
Keyword(s):  
Gadus Morhua ◽  
In Vitro Model ◽  
Atlantic Cod ◽  
Polar Cod ◽  
Dependent Manner ◽  
Boreogadus Saida ◽  
Polar Cod Boreogadus Saida ◽  
Vitro Model ◽  
Skin Healing

Fish skin is a multifunctional barrier tissue with high regeneration capacity that interacts with the surrounding environment and provides protection. Functional importance, high complexity and activity make skin an attractive tissue for studying the effects of environmental challenges and chemical stressors in fish. The aim of this work was to characterize skin from polar cod (Boreogadus saida) and Atlantic cod (Gadus morhua), and to test cod skin as an in vitro model in exposure studies. Both species have similar skin structures including epidermis, mucous cells, club cells and scales. However, microarchitectural differences were detected; Atlantic cod has a smooth epidermal surface and overlapping scales, whereas polar cod has a folded outer surface and discontinuous scales. Genome-wide microarray found 6.5k genes with expression differences, which suggested more active turnover of proteins, proliferation and motility of cells in skin of polar cod. Hydrogen peroxide (H2O2) was used to examine skin responses. Transcriptome response was stronger in the skin of polar cod, with 155 differentially expressed genes. The skin from Atlantic cod was further used to develop a cell culture. H2O2 decreased the cell migration rate in a dose-dependent manner, which could indicate reduced skin healing capacity. The results revealed novel skin structures and confirmed that the skin from cod is a promising tissue for evaluation of stressors.

scholarly journals Stock structure of Atlantic cod (Gadus morhua) in West Greenland waters: implications of transport and migration

2004 ◽  
Vol 61 (6) ◽  
pp. 972-982 ◽  
Author(s):  
Marie Storr-Paulsen ◽  
Kai Wieland ◽  
Holger Hovgård ◽  
Hans-Joachim Rätz
Keyword(s):  
Gadus Morhua ◽  
Atlantic Cod ◽  
Stock Structure ◽  
West Greenland ◽  
The Past ◽  
Migration Behaviour ◽  
And Migration ◽  
Abundance And Distribution ◽  
Icelandic Waters

Abstract Atlantic cod in West Greenland waters have varied greatly in abundance and distribution in the past decades. Strong year classes yielded good catches inshore and offshore in the late 1980s, but since then cod have been nearly absent offshore and the inshore fishery has been depressed, though there has been a small increase inshore over the past few years. Different components contribute to the Greenland cod stock, and re-analysed tagging experiments indicate that migration behaviour differs between them. Inshore cod are sedentary, with almost no migration between different fjord systems. In contrast, there are many cases of alongshore migration of cod tagged on the offshore fishing banks. Further, observations have been made of occasional migrations from offshore to inshore, notably so in years of good recruitment originating from Icelandic waters.

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