Dispersal and growth of pelagic juvenile Arcto—Norwegian cod (Gadus morhua), inferred from otolith microstructure and water temperature

1993 ◽  
Vol 50 (3) ◽  
pp. 261-270 ◽  
Author(s):  
I Suthers
Keyword(s):  
Water Temperature ◽  
Gadus Morhua ◽  
Otolith Microstructure ◽  
Pelagic Juvenile

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.

The use of otolith microstructure to estimate age in adult Atlantic cod Gadus morhua

2010 ◽  
Vol 76 (7) ◽  
pp. 1640-1654 ◽  
Author(s):  
K. Hüssy ◽  
H.-H. Hinrichsen ◽  
D. P. Fey ◽  
Y. Walther ◽  
A. Velasco
Keyword(s):  
Gadus Morhua ◽  
Atlantic Cod ◽  
Otolith Microstructure

Water-Thawing of Frozen Cod Blocks

1964 ◽  
Vol 21 (1) ◽  
pp. 115-131 ◽  
Author(s):  
W. A. MacCallum ◽  
D. G. Ellis
Keyword(s):  
Water Temperature ◽  
Sodium Alginate ◽  
Gadus Morhua ◽  
Individual Fish ◽  
Block Height ◽  
Intermediate Time ◽  
Water Recirculation ◽  
The Times ◽  
Thawing Rate ◽  
Better Than

Thawing time for frozen blocks of dressed cod (Gadus morhua) was investigated. Observations were made on the effect of size of individual fish, water recirculation rates, water temperature, block height, thickness and orientation, separation of individuals from the block at some intermediate time, and the use of sodium alginate to promote quicker thawing. Over the range investigated, the first two variables did not affect thawing rate; the remainder were of importance. Blocks 4 and [Formula: see text] inches (102 and 115 mm) thick, weighing 75–80 lb (34–37 kg), were separated and thawed in 60°F (15.5 °C) water in about 3 and [Formula: see text], respectively. These times were equal to or better than the times for freezing between plates under best local commercial conditions. In comparison, similar blocks can be thawed in about [Formula: see text] in a commercially available dielectric thawer. Thawing blocks of dressed fish in recirculated water thus merits consideration with other methods.

An Age- and Temperature-Mediated Growth Model for Cod (Gadus morhua) and Haddock (Melanogrammus aeglefinus) Larvae in the Gulf of Maine

1989 ◽  
Vol 46 (4) ◽  
pp. 603-613 ◽  
Author(s):  
Steven E. Campana ◽  
Peter C. F. Hurley
Keyword(s):  
Growth Rate ◽  
Growth Model ◽  
Gadus Morhua ◽  
Gulf Of Maine ◽  
Larval Fish ◽  
Fish Growth ◽  
Melanogrammus Aeglefinus ◽  
Temperature Record ◽  
Otolith Microstructure ◽  
Haddock Melanogrammus Aeglefinus

While field studies of larval fish growth require an easily parameterized growth model, simple relationships between size and age are seldom applicable to other populations and/or environments. The model presented here attempts to bridge the gap between simple age–length regressions and more sophisticated experiment-based models by incorporating a temperature term as a function of absolute growth rate. Growth is assumed to be logistic, with temperature influencing growth rate parabolically on a daily basis. The integrated form of the model provides an estimate of length-at-age of the larva. When fitted to a variety of independent cod (Gadus morhua) and haddock (Melanogrammus aeglefinus) data sets collected in the Gulf of Maine, the model performed with minimal bias despite the absence of a food availability term. Larval age data were generated through validated otolith microstructure examinations, although the resolution limits of light microscopy introduced a small degree of bias (2–3 d) into the estimates. The daily temperature record was generated from a sinusoidal model using monthly mean temperatures. Since otolith microstructure examination and remote sensing of temperature are established techniques, this model may prove useful in other larval studies.

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