Improving the age reading of East Greenland Atlantic cod ( Gadus morhua ) by determining otolith growth zone timing and annuli widths

2020 ◽  
Vol 27 (6) ◽  
pp. 628-632
Author(s):  
Mette Svantemann Lyngby ◽  
Frank Rigét ◽  
Anja Retzel ◽  
Rasmus Hedeholm ◽  
Peter Grønkjær
Keyword(s):  
Gadus Morhua ◽  
Atlantic Cod ◽  
Growth Zone ◽  
Otolith Growth ◽  
East Greenland ◽  
Age Reading

Estimating population age structure using otolith morphometrics: a test with known-age Atlantic cod (Gadus morhua) individuals

2008 ◽  
Vol 65 (11) ◽  
pp. 2342-2350 ◽  
Author(s):  
P. Doering-Arjes ◽  
M. Cardinale ◽  
H. Mosegaard
Keyword(s):  
Gadus Morhua ◽  
Atlantic Cod ◽  
Stock Assessment ◽  
Otolith Growth ◽  
Otolith Shape ◽  
Traditional Age ◽  
Ageing Processes ◽  
Different Populations ◽  
Population And Environment ◽  
Age Reading

Traditional age reading is a rather subjective method that lacks true reproducibility, producing ageing error that propagates up to stock assessment. One alternative is represented by the use of otolith morphometrics as a predictor of age. An important issue with such a method is that it requires known-age fish individuals. Here we used known-age Atlantic cod ( Gadus morhua ) from the Faroe Bank and Faroe Plateau stocks. Cod populations usually show quite large variation in growth rates and otolith shape. We showed that including otolith morphometrics into ageing processes has the potential to make ageing objective, accurate, and fast. Calibration analysis indicated that a known-age sample from the same population and environment is needed to obtain robust calibration; using a sample from a different stock more than doubles the error rate, even in the case of genetically highly related populations. The intercalibration method was successful but generalization from one stock to another remains problematic. The development of an otolith growth model is needed for generalization if an operational method for different populations is required in the future.

Otolith growth and zone formation during first maturity and spawning of Atlantic cod (Gadus morhua)

2020 ◽  
Vol 77 (1) ◽  
pp. 113-123 ◽  
Author(s):  
Christian Irgens ◽  
Arild Folkvord ◽  
Håkon Otterå ◽  
Olav S. Kjesbu
Keyword(s):  
Gadus Morhua ◽  
Barents Sea ◽  
Atlantic Cod ◽  
Somatic Growth ◽  
Otolith Growth ◽  
Zone Formation ◽  
Stock Biomass ◽  
Tank Experiment ◽  
The Individual ◽  
First Maturity

Specific impacts of somatic growth, sexual maturation, and spawning events on otolith zone formation in Atlantic cod (Gadus morhua) were assessed in a 33-month tank experiment, using Barents Sea cod and Norwegian coastal cod. High and low feeding ration combinations were used to mimic environmental stressors in the field. For both stocks, apparent macrostructural “spawning zones” in otoliths are registered in statutory stock monitoring programs to estimate age at maturity, thus adding key information to stock biomass assessments. We found that substantial energy investments in reproduction caused reductions in otolith growth and altered proportional width between translucent and opaque zones. These effects, however, were only statistically significant among individuals with high reproductive investments, while otoliths from individuals with low investments did not differ from the otoliths for immatures. Reproduction may thus not necessarily induce spawning zones, and alternatively, spawning zones may not necessarily reflect reproduction. Altogether, this suggests that the individual energy level, as a premise for metabolic activity, plays a key role in the formation of such zones and thus is related to environmental conditions.

Atlantic cod (Gadus morhua) growth and otolith accretion characteristics modelled in a bioenergetics context

2004 ◽  
Vol 61 (6) ◽  
pp. 1021-1031 ◽  
Author(s):  
K Hüssy ◽  
H Mosegaard
Keyword(s):  
Measurement Errors ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Somatic Growth ◽  
Whole Body ◽  
Model Parameters ◽  
Otolith Growth ◽  
Body Protein ◽  
Highly Correlated ◽  
Protein Incorporation

The purpose of this work is to present a conceptual model for fish otolith growth in which somatic growth is related to otolith growth and opacity. The model is based on known mechanisms of CaCO3 and protein incorporation into the otolith. Model parameters were derived from laboratory experiments and from the literature. A sensitivity analysis showed that the model was robust to measurement errors in most input parameters. The most sensitive parameters were the exponents of the otolith length–weight and otolith protein – whole-body protein synthesis relationships and the proportionality constant between metabolism and otolith growth rate. Application to experimental data resulted in good agreement between back-calculated and observed fish sizes. In the growth experiment, the average back-calculated weights were slightly lower than the average observed weights, but the correlation was highly significant. In the starvation experiment, the back-calculated weights were also highly correlated with observed weights, with slightly declining residuals with fish size. Unlike previous back-calculation methods, this model has the ability to detect periods of starvation and estimate growth histories in both growing and starving fish.

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.

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