The Ecology of Atlantic Cod (Gadus morhua) in Canadian Arctic Lakes

ARCTIC ◽  
2011 ◽  
Vol 64 (2) ◽  
Author(s):  
David C. Hardie ◽  
Jeffrey A. Hutchings
Keyword(s):  
Gadus Morhua ◽  
Atlantic Cod ◽  
Canadian Arctic ◽  
Arctic Lakes

The effects of isolation and colonization history on the genetic structure of marine-relict populations of Atlantic cod (Gadus morhua) in the Canadian Arctic

2006 ◽  
Vol 63 (8) ◽  
pp. 1830-1839 ◽  
Author(s):  
David C Hardie ◽  
Roxanne M Gillett ◽  
Jeffrey A Hutchings
Keyword(s):  
Gadus Morhua ◽  
Atlantic Cod ◽  
Allelic Diversity ◽  
Canadian Arctic ◽  
Environmental Stochasticity ◽  
Arctic Lakes ◽  
The Arctic ◽  
Effective Population ◽  
Eastern Canada ◽  
High Allelic Diversity

The genetic consequences of extended periods at low population size are fundamental to the conservation of depleted species such as the Atlantic cod (Gadus morhua). We compared microsatellite genetic variability among cod populations in Canadian Arctic lakes with that of Gilbert Bay resident and inshore cod from eastern Canada. The Arctic populations had the lowest genetic diversity and were the most strongly genetically structured and distinct. By contrast, eastern Canadian samples expressed high allelic diversity and were not significantly genetically structured or distinct relative to each other, whereas Gilbert Bay resident cod were intermediate to the Arctic and eastern Canadian groups. Our results are consistent with the hypothesis that the Arctic populations were colonized between 8000 and 5000 years ago and have experienced little or no gene flow since that time. Despite isolation at the extreme of the species' range, the Arctic populations have retained relatively high heterozygosities and high genetic effective population sizes relative to census sizes (Ne–Nc ratios). Potential explanations for this include the absence of fishing pressure, allowing for the persistence of large, highly fecund individuals, as well as biotic (e.g., absence of planktivores) and abiotic (e.g., low environmental stochasticity) factors in the Arctic lakes that minimize individual variance in reproductive success.

Effects of temperature on life history set the sensitivity to fishing in Atlantic cod Gadus morhua

2014 ◽  
Vol 514 ◽  
pp. 217-229 ◽  
Author(s):  
HY Wang ◽  
LW Botsford ◽  
JW White ◽  
MJ Fogarty ◽  
F Juanes ◽  
...  
Keyword(s):  
Life History ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Effects Of Temperature

Responses of Atlantic cod Gadus morhua head kidney leukocytes to phytase produced by gastrointestinal-derived bacteria

2009 ◽  
Vol 36 (4) ◽  
pp. 883-891 ◽  
Author(s):  
Carlo C. Lazado ◽  
Christopher Marlowe A. Caipang ◽  
Sanchala Gallage ◽  
Monica F. Brinchmann ◽  
Viswanath Kiron
Keyword(s):  
Gadus Morhua ◽  
Atlantic Cod ◽  
Head Kidney

Some recent data on sperm morphology and motility kinetics in Atlantic cod (Gadus morhua L.)

2021 ◽  
Author(s):  
Sayyed Mohammad Hadi Alavi ◽  
Azadeh Hatef ◽  
Ian A.E. Butts ◽  
Olga Bondarenko ◽  
Jacky Cosson ◽  
...  
Keyword(s):  
Gadus Morhua ◽  
Sperm Morphology ◽  
Atlantic Cod

Natural mortality from poor condition in Atlantic cod (Gadus morhua)

2000 ◽  
Vol 57 (4) ◽  
pp. 826-836 ◽  
Author(s):  
Jean-Denis Dutil ◽  
Yvan Lambert
Keyword(s):  
Gadus Morhua ◽  
Atlantic Cod ◽  
Negative Impact ◽  
Fish Muscle ◽  
Early Summer ◽  
Wild Fish ◽  
Natural Mortality ◽  
Muscle Lactate ◽  
Lactate Dehydrogenase Activity ◽  
Poor Condition

The extent of energy depletion was assessed in Atlantic cod (Gadus morhua) in spring and early summer (1993-1995) to assess relationships between poor condition and natural mortality. Several indices of condition were compared in wild fish in the northern Gulf of St. Lawrence and in fish exposed to a prolonged period of starvation in laboratory experiments. Discriminant analyses classified only a small fraction of the wild fish as similar to cod that did not survive and a much larger fraction as similar to cod that survived starvation. This percentage increased from April to May and peaked in June 1993 and 1994. Condition factor and muscle somatic index allowed a clear distinction between live and dead fish. Muscle lactate dehydrogenase activity suggested that cod had experienced a period of negative growth early in 1993, 1994, and 1995. Fish classified as similar to starved individuals were characterized by a higher gonad to liver mass ratio than others. Reproduction may have a negative impact on survival not only in spring but also later into summer, as some individuals were found not to have recovered by late summer. This study shows that natural mortality from poor condition contributed to lower production in the early 1990s.

scholarly journals Gastrointestinal microbial community changes in Atlantic cod (Gadus morhua) exposed to crude oil

2018 ◽  
Vol 18 (1) ◽  
Author(s):  
Andrea Bagi ◽  
Even Sannes Riiser ◽  
Hilde Steine Molland ◽  
Bastiaan Star ◽  
Thomas H. A. Haverkamp ◽  
...  
Keyword(s):  
Microbial Community ◽  
Crude Oil ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Community Changes

scholarly journals Development of Atlantic cod (Gadus morhua) exposed to produced water during early life stages: Effects on embryos, larvae, and juvenile fish

2010 ◽  
Vol 70 (5) ◽  
pp. 383-394 ◽  
Author(s):  
Sonnich Meier ◽  
H. Craig Morton ◽  
Gunnar Nyhammer ◽  
Bjørn Einar Grøsvik ◽  
Valeri Makhotin ◽  
...  
Keyword(s):  
Early Life ◽  
Gadus Morhua ◽  
Produced Water ◽  
Atlantic Cod ◽  
Juvenile Fish ◽  
Life Stages ◽  
Early Life Stages

Induction of triploidy in Atlantic cod (Gadus morhua L.) by thermal shocks

Aquaculture ◽  
2007 ◽  
Vol 272 ◽  
pp. S276
Author(s):  
A. Kettunen ◽  
G. Kauric ◽  
S. Peruzzi
Keyword(s):  
Gadus Morhua ◽  
Atlantic Cod ◽  
Thermal Shocks

Spawning behaviour of Atlantic cod, Gadus morhua: evidence of mate competition and mate choice in a broadcast spawner

1999 ◽  
Vol 56 (1) ◽  
pp. 97-104 ◽  
Author(s):  
Jeffrey A Hutchings ◽  
Todd D Bishop ◽  
Carolyn R McGregor-Shaw
Keyword(s):  
Mate Choice ◽  
Gadus Morhua ◽  
Dna Analysis ◽  
Atlantic Cod ◽  
Multiple Paternity ◽  
Reproductive Behaviour ◽  
Male Dominance ◽  
Male Body ◽  
Experimental Conditions ◽  
Spawning Period

We quantified individual differences in Atlantic cod, Gadus morhua, reproductive behaviour at a field-reported spawning density under experimental conditions. Marked individuals (nine females, seven males) were observed twice daily and videotaped continuously for 9 weeks at ambient photoperiod and temperature in a large tank (60 m3). Agonistic interactions appeared to maintain a size-based dominance hierarchy among males. Multiple paternity per spawning bout, revealed by microsatellite DNA analysis, suggested a link between dominance and fertilization success. Interactions between sexes were dominated by the circling of females by males. Predicated by vertical separation from males, and after descending to the bottom, a motionless female would be circled up to 17 times, often by one male per circling bout but by several males throughout the spawning period. Although circling frequency increased with male dominance and male body size, initiation and termination of this behaviour appeared to be under female control. Circling provides opportunities for males to gain individual access to reproductive females and for females to assess the quality of potential mates. Our evidence for nonrandom mate choice and for male-male competition and display has implications for Atlantic cod mating systems and effects of fishing on their reproductive success.

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