Age-dependent distribution of demersal juvenile Atlantic cod (Gadus morhua) in inshore/offshore northeast Newfoundland

1997 ◽  
Vol 54 (S1) ◽  
pp. 168-176 ◽  
Author(s):  
E L Dalley ◽  
J T Anderson
Keyword(s):  
Gadus Morhua ◽  
Atlantic Cod ◽  
Age Dependent

scholarly journals Exploitation drives an ontogenetic-like deepening in marine fish

2018 ◽  
Vol 115 (25) ◽  
pp. 6422-6427 ◽  
Author(s):  
Kenneth T. Frank ◽  
Brian Petrie ◽  
William C. Leggett ◽  
Daniel G. Boyce
Keyword(s):  
Environmental Factors ◽  
North Sea ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Fish Distribution ◽  
Time Dependent ◽  
Technological Changes ◽  
Age Related ◽  
Age Dependent ◽  
Low Amplitude

Virtually all studies reporting deepening with increasing size or age by fishes involve commercially harvested species. Studies of North Sea plaice in the early 1900s first documented this phenomenon (named Heincke’s law); it occurred at a time of intensive harvesting and rapid technological changes in fishing methods. The possibility that this deepening might be the result of harvesting has never been evaluated. Instead, age- or size-related deepening have been credited to interactions between density-dependent food resources and density-independent environmental factors. Recently, time-dependent depth variations have been ascribed to ocean warming. We use a model, initialized from observations of Atlantic cod (Gadus morhua) on the eastern Scotian Shelf, where an age-dependent deepening of ∼60 m was observed, to assess the effect of size- and depth-selective exploitation on fish distribution. Exploitation restricted to the upper 80 m can account for ∼72% of the observed deepening; by extending exploitation to 120 m, all of the deepening can be accounted for. In the absence of fishing, the model indicated no age-related deepening. Observations of depth distributions of older cod during a moratorium on fishing supported this prediction; however, younger cod exhibited low-amplitude deepening (10–15 m) suggestive of an ontogenetic response. The implications of these findings are manifold, particularly as they relate to hypotheses advanced to explain the ecological and evolutionary basis for ontogenetic deepening and to recent calls for the adoption of evidence of species deepening as a biotic indicator or “footprint” of warming seas.

The risk of running on empty: the influence of age on starvation and gut fullness in larval Atlantic cod (Gadus morhua)

2003 ◽  
Vol 60 (10) ◽  
pp. 1289-1298 ◽  
Author(s):  
Adrian Jordaan ◽  
Joseph A Brown
Keyword(s):  
Gadus Morhua ◽  
Atlantic Cod ◽  
Day Treatment ◽  
Yolk Sac ◽  
Activity Levels ◽  
Activity Data ◽  
First Feeding ◽  
Age Dependent ◽  
Gut Fullness ◽  
Set Up

Two experiments were set up to evaluate whether the response of Atlantic cod (Gadus morhua) larvae to no-prey conditions changes with age. The first experiment was designed to test for age-specific starvation with starvation trials at 0, 5, 15, 30, and 45 days after hatching. Mortality, length, and swimming activity data were collected. A second experiment was conducted to determine the effect of non-feeding conditions on the residency of prey in the gut at 5, 15, 30, and 45 days after hatching. The results of experiment 1 indicated that mortality occurred most rapidly at 15 and 30 days and was delayed during the yolk-sac period (day 0). Larvae in non-fed treatments showed significantly lower activity levels, except in the 45-day treatment, and the reduction in activity occurred before the onset of mortality. In experiment 2, gut residencies displayed an age-dependent response, with 5- and 45-day-old larvae having significantly shorter residency times. We conclude that beyond the yolk-sac period, cod larvae exhibit an age-dependent trade-off between growth and starvation risk. Larval age also influences patterns of gut fullness over time, with the fastest rates of gut clearance found at first-feeding and metamorphosis.

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
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