Erratum: Comparison of size-at-age of larval Atlantic cod (Gadus morhua) from different populations based on size- and temperature-dependent growth models

2007 ◽  
Vol 64 (3) ◽  
pp. 583-585 ◽  
Author(s):  
A Folkvord
Keyword(s):  
Gadus Morhua ◽  
Atlantic Cod ◽  
Growth Models ◽  
Temperature Dependent ◽  
Different Populations ◽  
Dependent Growth ◽  
Size At Age

Comparison of size-at-age of larval Atlantic cod (Gadus morhua) from different populations based on size- and temperature-dependent growth models

2005 ◽  
Vol 62 (5) ◽  
pp. 1037-1052 ◽  
Author(s):  
A Folkvord
Keyword(s):  
Growth Rates ◽  
Laboratory Experiments ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Growth Models ◽  
Larval Growth ◽  
Growth Potential ◽  
Temperature History ◽  
Temperature Dependent ◽  
Dependent Growth

This study presents the first intraspecific evaluation of larval growth performance across several different experimental scales, environments, and regions of a marine fish species. Size- and temperature-dependent growth models for larval and early juvenile Atlantic cod (Gadus morhua) are developed based on selected laboratory experiments with cod fed in excess. Observed sizes-at-age of cod from several experiments and stocks are compared with predictions from the models using initial size and ambient temperature history as inputs. Comparisons with results from other laboratory experiments reveal that the model predictions represent relatively high growth rates. Results from enclosure experiments under controlled seminatural conditions generally provide growth rates similar to those predicted from the models. The models therefore produce suitable reference growth predictions against which field-based growth estimates can be compared. These comparisons suggest that surviving cod larvae in the sea typically grow at rates close to their size- and temperature-dependent capacity. This suggests that climatic influences will strongly affect the year-to-year variations in growth of cod during their early life history owing to their markedly temperature-dependent growth potential.

Density-versus temperature-dependent growth of Atlantic cod (Gadus morhua) in the Gulf of St. Lawrence and on the Scotian Shelf

2003 ◽  
Vol 59 (3) ◽  
pp. 327-341 ◽  
Author(s):  
D.P Swain ◽  
A.F Sinclair ◽  
M Castonguay ◽  
G.A Chouinard ◽  
K.F Drinkwater ◽  
...  
Keyword(s):  
Gadus Morhua ◽  
Atlantic Cod ◽  
Temperature Dependent ◽  
Scotian Shelf ◽  
Dependent Growth

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.

Depth-dependent vertebral number of Atlantic cod (Gadus morhua) on the Magdalen Shallows and Scotian Shelf: stock mixing or microgeographic trends within populations?

2000 ◽  
Vol 57 (12) ◽  
pp. 2393-2401 ◽  
Author(s):  
D P Swain ◽  
K T Frank
Keyword(s):  
Gadus Morhua ◽  
Atlantic Cod ◽  
Spatial Scales ◽  
Relative Length ◽  
Scotian Shelf ◽  
Age Classes ◽  
Vertebral Number ◽  
Size At Age ◽  
Stock Mixing ◽  
Summer Feeding

We examined spatial variation in the vertebral number of Atlantic cod (Gadus morhua) during the summer feeding season in the southern Gulf of St. Lawrence and on the Scotian Shelf. Mean vertebral number increased significantly with depth in the southern Gulf and on the northeastern Scotian Shelf but not on the southwestern Scotian Shelf. In the southern Gulf, where sampling was most extensive, mean vertebral number increased steadily as depth increased from 25 m to over 175 m. Mean vertebral number was also strongly related to relative length within age-classes, with the larger fish at age having more vertebrae. However, the association between vertebral number and depth could not be attributed to confounding between depth and size at age. These results indicate either unexpected mixing between neighbouring cod populations or unexpected structure at fine spatial scales within cod populations.

scholarly journals Trade-offs between growth and reproduction in wild Atlantic cod

2014 ◽  
Vol 71 (7) ◽  
pp. 1106-1112 ◽  
Author(s):  
Arild Folkvord ◽  
Christian Jørgensen ◽  
Knut Korsbrekke ◽  
Richard D.M. Nash ◽  
Trygve Nilsen ◽  
...  
Keyword(s):  
Gadus Morhua ◽  
Atlantic Cod ◽  
Life History Strategy ◽  
Skipped Spawning ◽  
Growth Increments ◽  
Trade Offs ◽  
Survival And Reproduction ◽  
Size At Age ◽  
Allocation Strategies ◽  
Growth And Reproduction

Animals partition and trade off their resources between competing needs such as growth, maintenance, and reproduction. Over a lifetime, allocation strategies should result in distinct trajectories for growth, survival, and reproduction, but such longitudinal individual data are difficult to reconstruct for wild animals and especially marine fish. We were able to reconstruct two of these trajectories in wild-caught Northeast Arctic cod (Gadus morhua) females: size-at-age was back-calculated from otolith growth increments, and recent spawning history was reconstructed from postovulatory follicles and present oocyte development. Our findings indicate distinct trade-offs between length growth and reproduction. Fish that sexually matured early had attained a larger size at age 3 than immatures, but onset of reproduction caused slower growth compared with immatures. We found that 6- and 7-year-old females skipping spawning grew significantly more in the year of missed spawning than females spawning for the second consecutive year. The latter tentatively supports the hypothesis that skipped spawning may occur as an adaptive life-history strategy, given the potential future fecundity gain with increased size.

Temperature-Dependent Growth Models for South Dakota Yellow Perch,Perca flavescens, Fingerling Production

2004 ◽  
Vol 16 (1-2) ◽  
pp. 105-112 ◽  
Author(s):  
Michael L. Brown ◽  
Kevin A. Smith
Keyword(s):  
South Dakota ◽  
Yellow Perch ◽  
Growth Models ◽  
Perca Flavescens ◽  
Temperature Dependent ◽  
Dependent Growth

scholarly journals Evolutionary response to size-selective mortality in an exploited fish population

2007 ◽  
Vol 274 (1613) ◽  
pp. 1015-1022 ◽  
Author(s):  
Douglas P Swain ◽  
Alan F Sinclair ◽  
J Mark Hanson
Keyword(s):  
Gadus Morhua ◽  
Atlantic Cod ◽  
Fish Population ◽  
Fish Populations ◽  
Selective Mortality ◽  
Genetic Changes ◽  
Evolutionary Response ◽  
In The Wild ◽  
Size At Age ◽  
Change In Mean

Many collapsed fish populations have failed to recover after a decade or more with little fishing. This may reflect evolutionary change in response to the highly selective mortality imposed by fisheries. Recent experimental work has demonstrated a rapid genetic change in growth rate in response to size-selective harvesting of laboratory fish populations. Here, we use a 30-year time-series of back-calculated lengths-at-age to test for a genetic response to size-selective mortality in the wild in a heavily exploited population of Atlantic cod ( Gadus morhua ). Controlling for the effects of density- and temperature-dependent growth, the change in mean length of 4-year-old cod between offspring and their parental cohorts was positively correlated with the estimated selection differential experienced by the parental cohorts between this age and spawning. This result supports the hypothesis that there have been genetic changes in growth in this population in response to size-selective fishing. Such changes may account for the continued small size-at-age in this population despite good conditions for growth and little fishing for over a decade. This study highlights the need for management regimes that take into account the evolutionary consequences of fishing.

Spatial implications of a temperature-based growth model for Atlantic cod (Gadus morhua) off the eastern coast of Canada

1995 ◽  
Vol 52 (11) ◽  
pp. 2445-2456 ◽  
Author(s):  
S. E. Campana ◽  
R. K. Mohn ◽  
S. J. Smith ◽  
G. A. Chouinard
Keyword(s):  
Water Temperature ◽  
Growth Model ◽  
Bottom Water ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Eastern Coast ◽  
Bottom Water Temperature ◽  
Relative Growth ◽  
Contour Maps ◽  
Size At Age

Lengths at age of Atlantic cod (Gadus morhua) off the eastern coast of Canada vary up to three-fold among geographic regions, with Georges Bank and the southern Gulf of St. Lawrence being the regions of fastest and slowest growth, respectively. Colour-coded contour maps of length at ages 2–8 (n = 59 518) based on research vessel surveys between 1971 and 1992 clearly showed the spatial variations in size at age. Corresponding maps of July–September bottom water temperature appeared to reflect relative growth rate, whereas those for depth did not. A polynomial expansion of a temperature-based von Bertalanffy growth model appeared to fit the data well, with no residual patterns across most ages, lengths, temperatures, or years. Model predictions were also consistent with reported lengths at age for cod in other regions and countries. Declines in bottom water temperature over the past 5–10 years appear to be at least partly responsible for observed declines in size at age of the cod stock on the eastern Scotian Shelf.

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