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.

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.

Seasonal Variation in the Physiological Response of Atlantic Cod (Gadus morhua) to Low Salinity

1992 ◽  
Vol 49 (6) ◽  
pp. 1149-1156 ◽  
Author(s):  
J.-D. Dutil ◽  
J. Munro ◽  
C. Audet ◽  
M. Besner
Keyword(s):  
Skeletal Muscle ◽  
Seasonal Variation ◽  
Osmotic Pressure ◽  
Principal Components ◽  
Physiological Response ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Low Salinity ◽  
Natural Photoperiod ◽  
Highly Correlated

Plasma Na+, Cl−, K+, osmotic pressure, Cortisol, glucose, and protein, blood hemoglobin and hematocrit, and water content of skeletal muscle were measured at regular intervals during a 28-d period following the transfer of Atlantic cod (Gadus morhua) to waters of 7, 14, 21, and 28‰ (control) salinity. These experiments were repeated four times at 3-mo intervals under natural photoperiod and temperatures (0–10 °C). Exposure to 7‰ salinity caused large decreases in plasma Na+ in winter (25 mmol/L over 14 d) and in spring (32 mmol/L over 7 d) when the lowest value for the year was reached (156 mmol/L). Transfer to 14 and 21‰ salinity resulted in a slight decrease (maximum 4%) in plasma Na+ which was much smaller than the seasonal variation (14%) observed in controls. Hydration of skeletal muscle occurred only at 7‰ (2.3% maximum), but these changes were small compared with the seasonal variation (3.9%) observed in the controls. Principal components and clustering analyses showed that all ionic and osmotic variables measured were highly correlated while being only weakly associated with the condition or reproductive status of the fish. There were no indications that acclimation to low salinity was stressful for cod.

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.

Muscle growth and development in Atlantic cod larvae (Gadus morhua L.), related to different somatic growth rates

1999 ◽  
Vol 202 (15) ◽  
pp. 2111-2120 ◽  
Author(s):  
T.F. Galloway ◽  
E. Kjorsvik ◽  
H. Kryvi
Keyword(s):  
Gadus Morhua ◽  
White Muscle ◽  
Atlantic Cod ◽  
Muscle Growth ◽  
Somatic Growth ◽  
Cross Sectional Area ◽  
Muscle Fibres ◽  
Sectional Area ◽  
Cross Sectional ◽  
First Feeding

The present study describes the development of the axial musculature in first-feeding larvae of Atlantic cod (Gadus morhua L.) with different somatic growth rates achieved by using different nutritional conditions. Muscle growth was assessed by determining the number of muscle fibres (hyperplasia) and the growth of existing fibres (hypertrophy). Larvae were fed rotifers containing a high (1. 4; treatment 1) or low (0.2; treatment 2) ratio of docosahexaenoic acid to eicosapentaenoic acid from day 5 after hatching. From day 17, the larvae were fed Artemia nauplii with the same enrichment in both treatments. Treatment 1 gave the highest somatic growth rate and hence the highest dry mass at the end of the experiment, but no difference in larval standard length was found between treatments. In slow-growing larvae, higher priority was thus put into reaching a certain length than into increasing muscle mass. The largest fibres, which were present from hatching, increased in cross-sectional area during larval development, but no differences were found between treatments in the cross-sectional area of individual fibres or the total cross-sectional area of these fibres at the end of the experiment. The first white recruitment fibres were observed at the dorsal and ventral apices of the myotome at approximately the onset of first feeding (larval length 4.5 mm). In larvae 8.5 mm long, the total cross-sectional area of white muscle fibres in the treatment 2 group was 75 % of that in the treatment 1 group. The highest somatic growth rate was associated with an increased contribution of hyperplasia to axial white muscle growth. In the faster-growing larval group, the relative contribution of hyperplasia to the total white muscle cross-sectional area was 50 %, whereas it was 41 % in the slower-growing larval group. The subsequent growth potential may thus be negatively affected by inadequate larval feeding.

Evaluating the performance of a multispecies statistical catch-at-age model

2013 ◽  
Vol 70 (3) ◽  
pp. 470-484 ◽  
Author(s):  
Kiersten L. Curti ◽  
Jeremy S. Collie ◽  
Christopher M. Legault ◽  
Jason S. Link
Keyword(s):  
Species Interactions ◽  
Input Data ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Model Performance ◽  
Clupea Harengus ◽  
Model Parameters ◽  
Data Types ◽  
Commercial Catch ◽  
Important Species

Predation is a substantial source of mortality that is a function of the abundance of predator and prey species. This source of mortality creates a challenge of incorporating species interactions in statistical catch-at-age models in a way that accounts for the uncertainty in input data, parameters, and results. We developed a statistical, age-structured, multispecies model for three important species in the Georges Bank fish community: Atlantic cod (Gadus morhua), silver hake (Merluccius bilinearis), and Atlantic herring (Clupea harengus). The model was fit to commercial catch, survey, and diet data from 1978 to 2007. The estimated predation rates were high, compared with fishing mortality, and variable with time. The dynamics of the three species can be explained by the interplay between fishing and predation mortality. Monte Carlo simulations were used to evaluate the ability of the model to estimate parameters with known error introduced into each of the data types. The model parameters could be estimated with confidence from input data with error levels similar to those obtained from the model fit to the observed data. This evaluation of model performance should help to move multispecies statistical catch-at-age models from proof of concept to functional tools for ecosystem-based fisheries management.

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

Feeding and growth of Atlantic cod (Gadus morhua L.) in the eastern Baltic Sea under environmental change

2019 ◽  
Vol 77 (2) ◽  
pp. 624-632 ◽  
Author(s):  
Stefan Neuenfeldt ◽  
Valerio Bartolino ◽  
Alessandro Orio ◽  
Ken H Andersen ◽  
Niels G Andersen ◽  
...  
Keyword(s):  
Growth Rate ◽  
Baltic Sea ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Somatic Growth ◽  
Environmental Forcing ◽  
Average Growth ◽  
Scarce Resources ◽  
Size At Age ◽  
Eastern Baltic

Abstract Five decades of stomach content data allowed insight into the development of consumption, diet composition, and resulting somatic growth of Gadus morhua (Atlantic cod) in the eastern Baltic Sea. We show a recent reversal in feeding level over body length. Present feeding levels of small cod indicate severe growth limitation and increased starvation-related mortality. For young cod, the low growth rate and the high mortality rate are manifested through a reduction in size-at-age. The low feeding levels are likely the result of a decrease in benthic prey abundance due to increased hypoxic areas, while decreasing abundances of pelagic species in the area of cod distribution have prevented a compensatory shift in diet. Our study emphasizes that environmental forcing and the decline in pelagic prey caused changes in consumption and growth rates of small cod. The food reduction is amplified by stunted growth leading to high densities of cod of smaller size competing for the scarce resources. The average growth rate is negative, and only individuals with feeding levels well above average will survive, though growing slowly. These results suggest that the relation between consumption rate, somatic growth and predatorprey population densities is strongly environmentally mediated.

scholarly journals Comparative examination of scale-explicit biological and physical processes: recruitment of Pacific hake (Merluccius productus)

1999 ◽  
Vol 56 (S1) ◽  
pp. 170-179 ◽  
Author(s):  
John K Horne ◽  
Paul E Smith ◽  
David C Schneider
Keyword(s):  
Gadus Morhua ◽  
Atlantic Cod ◽  
Somatic Growth ◽  
Aquatic Organism ◽  
Physical Processes ◽  
Spatial And Temporal Scales ◽  
Merluccius Productus ◽  
Life History Stages ◽  
Capelin Mallotus Villosus ◽  
Current Region

The creation, maintenance, and destruction of aquatic organism distributions result from biological and physical processes that operate at different spatial and temporal scales. Rate diagrams plot and contour ratios of process rates as a function of spatial and temporal scale to summarize the relative importance of demographics, growth, and kinematics. We demonstrate the utility of this approach by examining physical and biological processes that influence the distribution and survival of larval and juvenile Pacific hake (Merluccius productus) in the California Current region. Processes that influence changes in hake biomass switch from mortality and drift among larvae to somatic growth and active locomotion among juveniles. Comparison of hake rate diagrams with those of capelin (Mallotus villosus) and Atlantic cod (Gadus morhua) show that dominant processes differ across scales, across life history stages, and across species.

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