scholarly journals Thermal biology and swimming performance of Atlantic cod (Gadus morhua) and haddock (Melanogrammus aeglefinus)

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e7784 ◽  
Author(s):  
Tommy Norin ◽  
Paula Canada ◽  
Jason A. Bailey ◽  
A. Kurt Gamperl
Keyword(s):  
Gadus Morhua ◽  
Metabolic Response ◽  
Atlantic Cod ◽  
Swimming Performance ◽  
Melanogrammus Aeglefinus ◽  
Thermal Biology ◽  
Oxygen Transport Capacity ◽  
Thermal Maximum ◽  
Commercially Important ◽  
Better Than

Atlantic cod (Gadus morhua) and haddock (Melanogrammus aeglefinus) are two commercially important marine fishes impacted by both overfishing and climate change. Increasing ocean temperatures are affecting the physiology of these species and causing changes in distribution, growth, and maturity. While the physiology of cod has been well investigated, that of haddock has received very little attention. Here, we measured the metabolic response to increasing temperatures, as well as the critical thermal maximum (CTmax), of cod acclimated to 8 and 12 °C and haddock acclimated to 12 °C. We also compared the swimming performance (critical swimming speed, Ucrit) of cod and haddock at 12 °C, as well as the Ucrit of 12 °C-acclimated cod acutely exposed to a higher-than-optimal temperature (16 °C). The CTmax for cod was 21.4 and 23.0 °C for 8- and 12 °C-acclimated fish, respectively, whereas that for the 12 °C-acclimated haddock was 23.9 °C. These values were all significantly different and show that haddock are more tolerant of high temperatures. The aerobic maximum metabolic rate (MMR) of swimming cod remained high at 16 °C, suggesting that maximum oxygen transport capacity was not limited at a temperature above optimal in this species. However, signs of impaired swimming (struggling) were becoming evident at 16 °C. Haddock were found to reach a higher Ucrit than cod at 12 °C (3.02 vs. 2.62 body lengths s−1, respectively), and at a lower MMR. Taken together, these results suggest that haddock perform better than cod in warmer conditions, and that haddock are the superior swimmer amongst the two species.

Recent Growth, Biochemical Composition and Prey Field of Larval Haddock (Melanogrammus aeglefinus) and Atlantic Cod (Gadus morhua) on Georges Bank

1987 ◽  
Vol 44 (1) ◽  
pp. 14-25 ◽  
Author(s):  
L. J. Buckley ◽  
R. G. Lough
Keyword(s):  
Gadus Morhua ◽  
Atlantic Cod ◽  
Dry Weight ◽  
Melanogrammus Aeglefinus ◽  
Good Growth ◽  
Georges Bank ◽  
Larval Population ◽  
Prey Biomass ◽  
Recent Growth ◽  
Haddock Melanogrammus Aeglefinus

A transect across southern Georges Bank in May 1983 showed higher levels of available prey for haddock (Melanogrammus aeglefinus) and cod (Gadus morhua) larvae at two stratified sites than at a well-mixed site. At the stratified sites, prey biomass was high (30–300 μg dry wt∙L−1) near the surface above the thermocline; values were lower and more uniform with depth (10–30 μg dry wt∙L−1) at the well-mixed site. Larval population centers generally coincided with prey biomass vertically. Recent growth in dry weight of haddock larvae as estimated by RNA–DNA ratio analysis was higher at the stratified sites (8–13%∙d−1) than at the well-mixed site (7%∙d−1). Larvae appeared to be in excellent condition at the stratified sites, but up to 50% of haddock larvae from the well-mixed site had RNA–DNA ratios in the range observed for starved larvae in the laboratory. Cod collected at the same site were in better condition and growing faster than haddock. The data support the hypotheses that (1) stratified conditions in the spring favor good growth and survival of haddock larvae and (2) cod larvae are better adapted to grow and survive in well-mixed waters at lower levels of available food than haddock larvae.

Fish Catches and Long-Term Tidal Cycles in Northwest Atlantic Fisheries: A Nonlinear Regression Approach

1987 ◽  
Vol 44 (11) ◽  
pp. 1890-1897 ◽  
Author(s):  
Paul Cabilio ◽  
David L. DeWolfe ◽  
Graham R. Daborn
Keyword(s):  
New England ◽  
Nonlinear Regression ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Significant Negative Correlation ◽  
Clupea Harengus ◽  
Atlantic Menhaden ◽  
Melanogrammus Aeglefinus ◽  
Grand Banks

Selected long-term fisheries catch data from the New England – Fundy area and the Grand Banks were examined for concordance between changes in fish catches and the 18.6-yr nodal cycle of the tides using a nonlinear regression model. Significant positive correlations were found for Atlantic cod (Gadus morhua), haddock (Melanogrammus aeglefinus), alewife (Alosa pseudoharengus), Atlantic herring (Clupea harengus harengus), and scallop (Placopecten magellanicus), with lag times that are biologically appropriate for the time from hatching to recruitment into the fishery. A significant negative correlation with the nodal cycle was evident for Atlantic menhaden (Brevoortia tyrannus), for which this area constitutes the most northerly part of its range. Cod catches on the Grand Banks showed no correlation with the nodal cycle. It is suggested that the correlations between the nodal cycle and the changes in fish catches are caused by correlated changes either in sea surface temperature or in productivity resulting from changes in the degree of vertical mixing.

scholarly journals Environmental DNA concentrations are correlated with regional biomass of Atlantic cod in oceanic waters

2019 ◽  
Vol 2 (1) ◽  
Author(s):  
Ian Salter ◽  
Mourits Joensen ◽  
Regin Kristiansen ◽  
Petur Steingrund ◽  
Poul Vestergaard
Keyword(s):  
Gadus Morhua ◽  
Atlantic Cod ◽  
Environmental Dna ◽  
Sampling Effort ◽  
Trawl Survey ◽  
Catch Per Unit Effort ◽  
Fish Stocks ◽  
Powerful Approach ◽  
Commercially Important ◽  
Positive Correlations

AbstractEnvironmental DNA (eDNA) has emerged as a powerful approach for studying marine fisheries and has the potential to negate some of the drawbacks of trawl surveys. However, successful applications in oceanic waters have to date been largely focused on qualitative descriptions of species inventories. Here we conducted a quantitative eDNA survey of Atlantic cod (Gadus morhua) in oceanic waters and compared it with results obtained from a standardized demersal trawl survey. Detection of eDNA originating from Atlantic cod was highly concordant (80%) with trawl catches. We observed significantly positive correlations between the regional integrals of Atlantic cod biomass (kg) and eDNA quantities (copies) (R2 = 0.79, P = 0.003) and between sampling effort-normalised Catch Per Unit Effort (kg hr−1) and eDNA concentrations (copies L−1) (R2 = 0.71, P = 0.008). These findings extend the potential application of environmental DNA to regional biomass assessments of commercially important fish stocks in the ocean.

scholarly journals Fecundity estimation of Atlantic cod (Gadus morhua) and haddock (Melanogrammus aeglefinus) of Georges Bank: Application of the autodiametric method

2009 ◽  
Vol 99 (1) ◽  
pp. 47-54 ◽  
Author(s):  
Alexandre Alonso-Fernández ◽  
Ann Carole Vallejo ◽  
Fran Saborido-Rey ◽  
Hilario Murua ◽  
Edward A. Trippel
Keyword(s):  
Gadus Morhua ◽  
Atlantic Cod ◽  
Melanogrammus Aeglefinus ◽  
Georges Bank ◽  
Haddock Melanogrammus Aeglefinus

scholarly journals The vertical separation of fish in the aft end of a demersal trawl

2009 ◽  
Vol 66 (4) ◽  
pp. 772-777 ◽  
Author(s):  
Ludvig Ahm Krag ◽  
René Holst ◽  
Niels Madsen
Keyword(s):  
Vertical Distribution ◽  
Gadus Morhua ◽  
Melanogrammus Aeglefinus ◽  
Multinomial Model ◽  
Vertical Separation ◽  
Commercially Important ◽  
Merlangius Merlangus ◽  
The Vertical Distribution ◽  
Haddock Melanogrammus Aeglefinus ◽  
Important Fish

Abstract Krag, L. A., Holst, R., and Madsen, N. 2009. The vertical separation of fish in the aft end of a demersal trawl. – ICES Journal of Marine Science, 66: 772–777. Two multi-compartment separator frames were used to study the vertical separation of some commercially important fish species in the aft end of a trawl, with the aim of separating cod (Gadus morhua) from other species. A non-linear multinomial model with random effects was used to analyse the data and to compare the performance of the two frames. The vertical distribution of cod in the aft end of the trawl was close to uniform, whereas haddock (Melanogrammus aeglefinus), whiting (Merlangius merlangus), plaice (Pleuronectes platessa), and lemon sole (Microstomus kitt) showed more uneven distributions. The use of guiding bars in the separator frame significantly (p < 0.05) increased the catch of cod, plaice, and lemon sole in the upper compartment. The vertical separation of cod was density-dependent; high densities of fish resulted in a more uniform distribution of cod. The species separations found differ from those reported from the studies of species separation in the region of the trawl mouth.

Recruitment to Northwest Atlantic Cod (Gadus morhua) and Haddock (Melanogrammus aeglefinus) Stocks: Influence of Stock Size and Climate

1987 ◽  
Vol 44 (1) ◽  
pp. 26-39 ◽  
Author(s):  
J. Anthony Koslow ◽  
Keith R. Thompson ◽  
William Silvert
Keyword(s):  
Large Scale ◽  
Gadus Morhua ◽  
Reproductive Output ◽  
Atlantic Cod ◽  
Low Frequency ◽  
Melanogrammus Aeglefinus ◽  
Northwest Atlantic ◽  
Biological Variables ◽  
Low Frequency Variability ◽  
Haddock Melanogrammus Aeglefinus

Year-class success of both Atlantic cod (Gadus morhua) and haddock (Melanogrammus aeglefinus) stocks in the northwest Atlantic exhibits large-scale coherence and low-frequency variability with apparent periodicities of 10–20 yr. Several physical and biological variables in the region exhibit similar large-scale coherence and apparent periodicity. Multiple regression analysis indicates that year-class success in northwest Atlantic cod stocks tends to be associated with large-scale meteorological patterns and offshore winds. Recruitment to most haddock stocks from the Scotian Shelf to Georges Bank is negatively associated with abundance of 0-group mackerel, which may be due to predation over winter and/or to a combination of environmental features including sea-surface temperature, large-scale atmospheric pressure systems, and freshwater outflows. Statistical analyses often did not define a unique set of variables that best predicted fishery recruitment due to widespread intercorrelations among environmental processes and the likelihood that not all relevant processes entered directly into the analyses. There is little evidence that stock reproductive output during the study period was significantly related to year-class success.

scholarly journals The effects of salinity change on the exercise performance of two Atlantic cod (Gadus morhua) populations inhabiting different environments

1996 ◽  
Vol 199 (6) ◽  
pp. 1295-1309 ◽  
Author(s):  
J Nelson ◽  
Y Tang ◽  
R Boutilier
Keyword(s):  
Metabolic Rate ◽  
Exercise Performance ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Swimming Performance ◽  
Extracellular Fluid ◽  
Blood Chemistry ◽  
Data Set ◽  
Environmental Salinity ◽  
Full Strength

The objective of this study was to determine whether differences in exercise physiology between Atlantic cod (Gadus morhua) populations from different salinity environments could be changed by acclimating individuals of each population to the natural salinity of the comparison population. The exercise-associated blood chemistry of cod from the brackish Bras d'Or lakes, which had previously been shown to be quite different from that of 'open-ocean' cod, changed to resemble the blood chemistry of their oceanic relatives after only 2 months of acclimation to full-strength salinity. In contrast, the blood chemistry of cod from the Scotian Shelf of the Northwest Atlantic Ocean showed little change after 2 months of acclimation to brackish water. These results demonstrate that the degree of osmoconformity to changes in environmental salinity is a population-specific not a species-specific trait. The blood chemistry differences between populations and salinities did not translate into differences in exercise performance: i.e. critical swimming speeds were statistically uniform across all combinations of population and salinity, although performance was more varied in fish swimming in 'non-native' waters. Other 'whole-animal' physiological characteristics, such as metabolic rate and the aerobic cost of transport, were dependent upon both population origin and the environmental salinity. Vigorous swimming was more energetically expensive at full-strength salinity than at 20 salinity, yet estimates of standard (i.e. resting) metabolic rate were lower for full-strength salinity. Environmental salinity also influenced the relative appearance of lactate and metabolic acid in the extracellular fluid compartment, with full-strength salinity favouring the relative appearance of lactate in the blood. Multivariate statistical analyses of this data set showed that, in contrast to other fish species and studies, differences in blood oxygen transport appear to account for some of the swimming performance differences seen in Atlantic cod at 2 &deg;C. The two experimental populations were cleanly separated by a principal components analysis, regardless of the salinity to which they were acclimated, confirming our earlier contention that these cod populations are physiologically distinct. A key feature of that distinctness is the greater phenotypic plasticity exhibited by the population from the more euryhaline, more eurythermal environment.

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