Comparative Survival and Growth of Two Strains of Atlantic Cod (Gadus morhua) through the Early Life Stages in a Marine Pond

1994 ◽  
Vol 51 (5) ◽  
pp. 1012-1023 ◽  
Author(s):  
Geir Blom ◽  
Terje Svåsand ◽  
Knut E. Jørstad ◽  
Håkon Otterå ◽  
Ole I. Paulsen ◽  
...  
Keyword(s):  
Body Size ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Larval Mortality ◽  
Food Limitation ◽  
Juvenile Stage ◽  
Average Growth ◽  
Juvenile Mortality ◽  
Early Juvenile Stage ◽  
Survival And Growth

Survival and growth of two strains of Atlantic cod (Gadus morhua) were compared through the larval and juvenile stages in a marine pond in western Norway in 1990 and 1991. Strain A was homozygous for the genetic marker allele GPI-1*30 at the glucose phosphate isomerase (GPI) locus expressed in white muscle, and Strain B possessed other GPI-1* genotypes, in 1990 the frequency of Strain B increased significantly from the larval to the juvenile stage; however, in 1991 the frequency of Strain A increased slightly but not significantly from the larval to the juvenile phase. Larval mortality did not differ significantly between strains any year, but juvenile mortality was significantly lower in Strain B in 1990 and Strain A in 1991. Average growth rates in length estimated from regressions were not significantly different between strains during the larval and juvenile period any year, but initial length was significantly larger in Strain B in 1990 and Strain A in 1991. Our results indicated that food limitation during the early juvenile stage induced differential size-selective mortality among the strains due to small differences in body size and actual age between strains. Body size did not become important for survival until the food-limited regime had occurred.

Density-Dependent Juvenile Mortality in Marine Demersal Fish

1993 ◽  
Vol 50 (8) ◽  
pp. 1576-1590 ◽  
Author(s):  
Ransom A. Myers ◽  
Noel G. Cadigan
Keyword(s):  
Atlantic Cod ◽  
Estimation Error ◽  
Juvenile Stage ◽  
Irish Sea ◽  
Melanogrammus Aeglefinus ◽  
Density Dependent ◽  
Juvenile Mortality ◽  
Density Dependent Mortality ◽  
Early Juvenile Stage ◽  
Dependent Mortality

We examine the hypothesis that population variability is created and regulated in the juvenile stage for demersal marine fish. Juvenile mortality is examined for 17 populations of Atlantic cod (Gadus morhua), haddock (Melanogrammus aeglefinus), whiting (Merlangius merlangus), plaice (Pleuronectes platessa), yellowtail flounder (Pleuronectes ferrugineus), and sole (Solea vulgaris) in the North Sea, Irish Sea, Barents Sea, Baltic Sea, and Northwest Atlantic. A latent variable covariance analysis of recruitment time series with measurement error is used to test hypotheses. We found strong evidence of density-dependent mortality within cohorts during the juvenile stage for cod, plaice, sole, and whiting; density-dependent mortality appears to be related to the log of juvenile abundance. There is evidence of negative autocorrelation between adjacent cohorts of cod; this pattern is consistent with density-dependent mortality between adjacent cohorts. The autocorrelations are positive for the flatfish examined. It is possible to obtain estimates of estimation error variances for populations if there are multiple research surveys of the same population. We conclude that the juvenile stage is very important for population regulation in most species but that the source of the variability in year class strength is in the larval stage or very early juvenile stage.

scholarly journals The relation between concentrations of ovarian trace elements and the body size of Atlantic cod Gadus morhua

2008 ◽  
Vol 65 (7) ◽  
pp. 1191-1197 ◽  
Author(s):  
A. Bang ◽  
P. Grønkjær ◽  
B. Lorenzen
Keyword(s):  
Trace Elements ◽  
Body Size ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
The Body ◽  
Small Fish ◽  
Female Size ◽  
Large Fish ◽  
Size Category ◽  
Linear Discriminant

Abstract Bang, A., Grønkjær, P., and Lorenzen, B. 2008. The relation between concentrations of ovarian trace elements and the body size of Atlantic cod Gadus morhua. – ICES Journal of Marine Science, 65: 1191–1197. Trace metals in the ovaries of fish are transferred from the female via the yolk to the offspring, which makes the early life stages susceptible to deleterious effects of potentially toxic elements contained in the ovaries. Here, the concentrations of 13 elements from the ovaries of 133 ripe female North Sea cod Gadus morhua weighing 0.2–18 kg were correlated with female size, accounting for differences in maturity and condition. Most elements were negatively correlated with the size variables weight, length and, especially, ovarian dry weight. Further, they were negatively correlated with maturity and condition. Many of the trace elements showed true size-dependence, but the correlations were generally weak. A linear discriminant analysis separated “small” and “large” fish at a length of 85 cm based on concentrations of Co, Mn, Se, and Zn, and correctly assigned 78 of 102 small fish and 23 of 31 large fish to their respective size category. This corresponds to an overall classification success of 75.9%. The results suggest that embryos and early larvae from small females are exposed to higher levels of potentially harmful metals. If the differences in trace element concentration influence survival success, this will add to the negative effects of size distribution truncation and declines in size-at-maturity experienced by many populations of cod.

Survival and Abundance of Young Atlantic Cod (Gadus morhua) and Haddock (Melanogrammus aeglefinus) as Indicators of Year-class Strength

1989 ◽  
Vol 46 (S1) ◽  
pp. s171-s182 ◽  
Author(s):  
Steven E. Campana ◽  
Kenneth T. Frank ◽  
Peter C. F. Hurley ◽  
Peter A. Koeller ◽  
Fred H. Page ◽  
...  
Keyword(s):  
Nova Scotia ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Larval Mortality ◽  
Larval Growth ◽  
Melanogrammus Aeglefinus ◽  
Larval Abundance ◽  
Life History Stage ◽  
Spawning Site ◽  
Haddock Melanogrammus Aeglefinus

To identify the life history stage(s) most influential in determining yearclass strength, we constructed and analyzed survival curves of the 1983, 1984, and 1985 cohorts of cod and haddock off Southwest Nova Scotia relative to their physical and biological environment. Relative abundance of each Atlantic cod (Gadus morhua) and haddock (Melanogrammus aeglefinus) yearclass was not reflected by egg or larval abundance in any year examined. However, abundance of both pelagic and settled juveniles did appear to reflect yearclass strength. Egg and larval mortality could not be consistently linked with advection from the spawning site, and did not covary with subsequent recruitment. In both species, mortality between the larval and juvenile stage was inversely correlated with yearclass strength, but sources of the mortality could not be identified. Larval growth was inversely related to mortality of the early larval stage and independent of larval abundance. However, juvenile growth was proportional to mortality and inversely related to abundance. Despite early life coexistence and similarities in spawning time and location, the relative yearclass strengths of cod and haddock in Southwest Nova Scotia were different, suggesting that the timing of local physical and biological events may play an important role in the recruitment success of these stocks.

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.

Spatiotemporal variations in juvenile mortality and cohort strength of Atlantic cod (Gadus morhua) off Newfoundland and Labrador

2020 ◽  
Vol 77 (3) ◽  
pp. 625-635
Author(s):  
Fan Zhang ◽  
Rick M. Rideout ◽  
Noel G. Cadigan
Keyword(s):  
Newfoundland And Labrador ◽  
Large Scale ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Survival Rates ◽  
Mortality Rates ◽  
Spatiotemporal Variations ◽  
Juvenile Mortality ◽  
Modelling Framework ◽  
Fish Recruitment

Juvenile mortality is an important factor affecting the spatiotemporal dynamics of fish recruitment, but estimation of the spatiotemporal variations in juvenile mortality rates remains challenging. We developed a state-space metapopulation dynamics model to simultaneously estimate spatiotemporal variations in juvenile mortality rates and cohort strength and applied this general modelling framework to data from multiple surveys for juvenile (ages 2–5) Atlantic cod (Gadus morhua) stocks off Newfoundland and Labrador (NL). We found large-scale synchronized dynamics of decreasing juvenile mortality rates and increasing cohort strength from offshore surveys off eastern and southeastern NL, suggesting improving reproduction and survival rates for juvenile cod. No synchronized patterns of juvenile mortality rates and cohort strength were detected for cod stocks off southern and western NL, indicating more complex cod population spatial structures in those areas. Our study demonstrates the potential of juvenile mortality to cause temporally variable and spatially synchronized dynamics of fish recruitment, and the spatial patterns of juvenile mortality and cohort strength indicate some potential mismatch between cod population structure and current management units off NL.

Male reproductive success and body size in Atlantic cod Gadus morhua L.

2001 ◽  
Vol 138 (6) ◽  
pp. 1077-1085 ◽  
Author(s):  
Not Available Not Available ◽  
Not Available Not Available ◽  
Not Available Not Available
Keyword(s):  
Body Size ◽  
Reproductive Success ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Male Reproductive Success

Energy losses due to routine and feeding metabolism in young-of-the-year juvenile Atlantic cod (Gadus morhua)

2003 ◽  
Vol 60 (8) ◽  
pp. 929-937 ◽  
Author(s):  
Myron A Peck ◽  
Lawrence J Buckley ◽  
David A Bengtson
Keyword(s):  
Body Size ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Effect Of Temperature ◽  
Energy Losses ◽  
The North ◽  
A Value ◽  
Different Temperatures ◽  
Body Sizes ◽  
Environmental Temperatures

We examined the effects of body size (3–13 cm total length) and temperature (4.5, 8.0, 12.0, and 15.5 °C) on routine (RR) and feeding (RSDA) energy losses by laboratory-reared, young-of-year juvenile Atlantic cod (Gadus morhua). The magnitude of the effect of temperature on RR, expressed via the Q10, was nonlinear. Q10 values were greatest at temperatures between 4.5 and 8.0 °C and were lowest between 8.0 and 15.5 °C, with larger fish tending to exhibit the greatest change in RR irrespective of the temperature combination. Energy losses resulting from RSDA were ~4% of consumed energy, a value less than half that estimated for larger, year-1+ juvenile cod fed similar-sized rations. Data from this and other studies were combined to generate an equation estimating routine energy loss at different temperatures and body sizes for cod. The equation describes RR over the eight orders of magnitude difference in body size from young larvae to adults within a range of environmental temperatures experienced by this species on Georges Bank and other areas in the North Atlantic.

Survival and growth traits at harvest of communally reared families of Atlantic cod (Gadus morhua)

Aquaculture ◽  
2010 ◽  
Vol 307 (1-2) ◽  
pp. 12-19 ◽  
Author(s):  
Amber F. Garber ◽  
J. Jane Tosh ◽  
Susan E. Fordham ◽  
Sophie Hubert ◽  
Gary Simpson ◽  
...  
Keyword(s):  
Gadus Morhua ◽  
Atlantic Cod ◽  
Growth Traits ◽  
Survival And Growth

Sperm competition and fertilization success in Atlantic cod (Gadus morhua): effect of sire size and condition factor on gamete quality

1999 ◽  
Vol 56 (12) ◽  
pp. 2315-2323 ◽  
Author(s):  
Ana Rakitin ◽  
Moira M Ferguson ◽  
Edward A Trippel
Keyword(s):  
Body Size ◽  
Sperm Competition ◽  
Gadus Morhua ◽  
Condition Factor ◽  
Atlantic Cod ◽  
Sperm Quality ◽  
Fertilization Success ◽  
Male Body ◽  
Single Female ◽  
Male Condition

Sperm competition experiments were conducted to test the null hypothesis that sperm quality is not affected by male body size in Atlantic cod (Gadus morhua). Genetic markers (allozymes) were used to determine the proportion of larvae sired by pairs of males when their sperm was combined with eggs of a single female simultaneously. Significant differences in fertilization success between males were not explained by differences in body size. Fertilization success was positively associated with male condition factor (K) and with spermatozoa density in each male's semen when equal volumes of semen from each male were used. Male K was positively associated with male fertilization success when the volume of semen used from each male was adjusted to add approximately equal numbers of spermatozoa from each male. The relative fertilization success of males varied depending on which female was the egg donor, suggesting that female "choice" at the gamete level may be occurring in cod.

Is Juvenile Natural Mortality in Marine Demersal Fish Variable?

1993 ◽  
Vol 50 (8) ◽  
pp. 1591-1598 ◽  
Author(s):  
Ransom A. Myers ◽  
Noel G. Cadigan
Keyword(s):  
Interannual Variability ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Demersal Fish ◽  
Independent Component ◽  
Melanogrammus Aeglefinus ◽  
Natural Mortality ◽  
Juvenile Mortality ◽  
Merlangius Merlangus ◽  
Haddock Melanogrammus Aeglefinus

We test the hypothesis that the interannual variability of the density-independent component of juvenile natural mortality is a major source of variability in abundance of marine demersal fish. Our tests use data on populations for which there are research surveys consisting of two simultaneous estimates of abundance of young juveniles soon after settlement and two more simultaneous estimates of the same cohort a year later. We applied our test to 14 populations of Atlantic cod (Gadus morhua), haddock (Melanogrammus aeglefinus), whiting (Merlangius merlangus), plaice (Pleuronectes platessa), and sole (Solea vulgaris). We conclude that, in all populations examined except North Sea sole, there was very little or no interannual variability in the density-independent component of juvenile mortality.

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