Histopathological effects of crude oil on Atlantic cod following chronic exposure

1984 ◽  
Vol 62 (10) ◽  
pp. 2038-2043 ◽  
Author(s):  
R. A. Khan ◽  
J. Kiceniuk
Keyword(s):  
Gadus Morhua ◽  
Atlantic Cod ◽  
Giant Cells ◽  
Water Soluble ◽  
Similar Concentration ◽  
Long Term Effect ◽  
Flow Through ◽  
Kidney Lesions ◽  
Histopathological Effects

To assess the long-term effect on the tissues of marine fish, Atlantic cod, Gadus morhua L., were exposed to water-soluble fractions of Venezuelan and Hibernia crude oils at concentrations of 50–300 ppb for 12–13 weeks in a flow-through seawater system. Histopathological changes in oil-exposed fish included increased numbers of mucus-producing epithelial cells, capillary dilation, lamellar hyperplasia, and fusion of adjacent filaments in gills, microvesicular formation in hepatocytes, delayed spermatogenesis with intratubular multinucleated giant cells, and an increase of melanomacrophage centers in the spleen and kidney. Lesions were more prevalent and severe in fish exposed to Hibernia crude than to Venezuelan crude at a similar concentration.

Effect of petroleum hydrocarbons on Atlantic cod, Gadus morhua, following chronic exposure

1987 ◽  
Vol 65 (3) ◽  
pp. 490-494 ◽  
Author(s):  
J. W. Kiceniuk ◽  
R. A. Khan
Keyword(s):  
Chronic Exposure ◽  
Gadus Morhua ◽  
Condition Factor ◽  
Atlantic Cod ◽  
System Control ◽  
Low Concentrations ◽  
Treated Fish ◽  
Flow Through ◽  
Oil Exposure

Experiments were conducted to ascertain the effects of crude oils at low concentrations on Atlantic cod (Gadus morhua) following long-term exposure (3–21 weeks) in a flow-through seawater system. Control and oil-treated fish were fed to satiation. Effects were assessed by comparing condition factor, organ indices, and hematological values with those of corresponding control animals. No mortality occurred but food consumption was significantly reduced in oil-treated cod, especially during summer–autumn. Condition factor and somatic indices of some organs were lower in oil-treated fish. Gall bladders were enlarged in oil-treated fish. Effects of oil exposure were less pronounced during winter, as food intake in both groups of fish was reduced considerably. The rate of gametogenesis was slower in male cod exposed to oil fractions in summer–autumn whereas spermeation was delayed in fish treated in winter–spring. These studies provide evidence that feeding, growth, and reproduction in male cod are biologically important variables that are affected following chronic exposure to petroleum.

Transition to an alternate state in a continental shelf ecosystem

2004 ◽  
Vol 61 (4) ◽  
pp. 505-510 ◽  
Author(s):  
Jae S Choi ◽  
Kenneth T Frank ◽  
William C Leggett ◽  
Ken Drinkwater
Keyword(s):  
Fish Species ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Demersal Fish ◽  
Commercial Fishing ◽  
Progressive Decline ◽  
Ecological Changes ◽  
Decadal Scale ◽  
Flow Through

The collapse of Atlantic cod (Gadus morhua) stocks in the northwest Atlantic Ocean ranks among the most dramatic and widely known ecological changes of the 20th century. Less widely known are the systemic changes that occurred within these areas prior to and coincident with the cod collapse. Our analysis of a fishery-independent, long-term, standardized database collected on the eastern Scotian Shelf off Nova Scotia revealed that during the past four decades, coherent, community-level reductions in body size, biomass, and physiological condition have occurred in the resident demersal fish species. The changes occurred over large spatial (>104 km2) and short temporal (<10 years) scales, suggesting a progressive decline in the nature and extent of the energy flow through the benthic system. The unexpected and persistent poor condition of a variety of morphologically and functionally dissimilar demersal fish species, living in an environment of reduced intra- and inter-specific competition, suggests a decoupling of the benthic– pelagic systems. This decoupling appears to be attributable to a cascading series of processes involving the cumulative removal of biomass resulting from commercial fishing, compensatory and self-stabilizing increases in pelagic fish biomass, and a decline in groundfish productivity exacerbated by decadal scale variability in water temperature and stratification.

Effect of age and temperature on amino acid composition and the content of different protein types of juvenile Atlantic cod (Gadus morhua) otoliths

2004 ◽  
Vol 61 (6) ◽  
pp. 1012-1020 ◽  
Author(s):  
K Hüssy ◽  
H Mosegaard ◽  
F Jessen
Keyword(s):  
Amino Acid ◽  
Amino Acid Composition ◽  
Acid Composition ◽  
Soluble Protein ◽  
Protein Fraction ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Water Soluble ◽  
Soluble Protein Fraction ◽  
Water Soluble Protein

The purpose of this study was to analyse the amino acid composition of otolith matrix protein, estimate the proportion of the water-soluble protein fraction, and analyse the effect of matrix composition on otolith visual appearance. Juvenile Atlantic cod (Gadus morhua) were reared under constant temperature and feeding conditions and sampled at the beginning and the end of the experiment. The amino acid composition was dominated by asparagine, glutamic acid, leucine, serine, and proline. A change in amino acid composition was observed with increasing temperature and time, caused by changing proportions of the water-soluble and -insoluble protein fractions. Feeding level had no effect. The relative content of water-soluble protein was linearly related to fish dry weight and temperature. Otolith opacity, defined as the percentage of incident light absorbed by an otolith section, did not differ significantly between experimental treatments. The soluble protein fraction had a positive, albeit insignificant, correlation with opacity. Using opacity and otolith volume, deposited total otolith protein content was estimated with an R2 of 0.91, where otolith volume alone explained 83% of the observed variation.

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.

Intergenerational valuation of fisheries resources can justify long-term conservation: a case study in Atlantic cod (Gadus morhua)

2005 ◽  
Vol 62 (5) ◽  
pp. 1104-1110 ◽  
Author(s):  
C H Ainsworth ◽  
U R Sumaila
Keyword(s):  
Discount Rate ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Ecosystem Model ◽  
Conventional Model ◽  
Fisheries Resources ◽  
Optimal Harvest ◽  
Harvest Policies

Where the conventional model of discounting advocates aggressive harvest policies, intergenerational discounting could have been used to render the historic gross overfishing of Atlantic cod (Gadus morhua) economically unappealing compared with a more conservative long-term strategy. Under these discounting approaches, we compare the historic harvest trend from 1985 (and projected postcollapse earnings) with theoretical optimal harvest profiles determined by an ecosystem model. The optimal scenarios generate less initial harvest than the historic profile but maintain the resource and provide greater yields over the long term. At a discount rate equal to market interest, we demonstrate that it was more economic under conventional valuation to harvest the cod stock to collapse than it would have been to sustain the population. However, under intergenerational valuation, the sustainable optimal scenarios outperform the actual harvest profile. Application of conventional discounting by fishing consortiums may be partly to blame for depletion, yet management fell short of even that ideal.

Short- and long-term effects of fish density and specific water flow on the welfare of Atlantic cod, Gadus morhua

Aquaculture ◽  
2011 ◽  
Vol 322-323 ◽  
pp. 184-190 ◽  
Author(s):  
Børge Damsgård ◽  
Frode Bjørklund ◽  
Helge K. Johnsen ◽  
Hilde Toften
Keyword(s):  
Water Flow ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Fish Density ◽  
Long Term Effects ◽  
Short And Long Term

scholarly journals Reproductive investment in Atlantic cod populations off Newfoundland: Contrasting trends between males and females

FACETS ◽  
2017 ◽  
Vol 2 (2) ◽  
pp. 660-681 ◽  
Author(s):  
Loïc Baulier ◽  
M. Joanne Morgan ◽  
George R. Lilly ◽  
Ulf Dieckmann ◽  
Mikko Heino
Keyword(s):  
Life History Theory ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Temporal Trends ◽  
Reproductive Investment ◽  
Male Reproductive Success ◽  
Density Dependent ◽  
Theoretical Predictions ◽  
Two Populations

Life history theory predicts selection for higher reproductive investment in response to increased mortality among mature individuals. We tested this prediction over the period from 1978 to 2013 for three populations of Atlantic cod ( Gadus morhua) off Newfoundland. These populations were heavily fished for a long period. We considered changes in standardized gonad weight as a proxy for changes in gonadal investment. We accounted for the allometry between gonad and body weight, individual body condition, water temperature, and potential spatial and density-dependent effects. Males display significant temporal trends in gonadal investment in all populations; in agreement with theoretical predictions, these trends show increased gonadal investments during the earlier part of the time series when mortality was high, with the trends leveling off or reversing after the later imposition of fishing moratoria. In contrast, females display patterns that are less consistent and expected; significant trends are detected only when accounting for density-dependent effects, with females in two populations unexpectedly showing a long-term decline in gonadal investment. Our results support the hypothesis that fisheries-induced evolution has occurred in gonadal investment in males, but not in females, and suggest that gonadal investment is more important for male reproductive success than expected in this lekking species.

scholarly journals Pilot study to investigate the effect of long-term exposure to high pCO2 on adult cod (Gadus morhua) otolith morphology and calcium carbonate deposition

2021 ◽  
Author(s):  
Clara Coll-Lladó ◽  
Felix Mittermayer ◽  
Paul Brian Webb ◽  
Nicola Allison ◽  
Catriona Clemmesen ◽  
...  
Keyword(s):  
Calcium Carbonate ◽  
Pilot Study ◽  
Ocean Acidification ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
High Pco2 ◽  
Juvenile Stages ◽  
Calcium Carbonate Deposition ◽  
Present Pilot Study

AbstractTo date the study of ocean acidification on fish otolith formation has been mainly focused on larval and juvenile stages. In the present pilot study, wild-captured adult Atlantic cod (Gadus morhua) were exposed to two different levels of pCO2, 422µatm (ambient, low pCO2) or 1091µatm (high pCO2), for a period of 30 weeks (from mid-October to early April 2014–2015) in order to study the effects on otolith size, shape and CaCO3 crystallization amongst other biological parameters. We found that otoliths from cod exposed to high pCO2 were slightly smaller (− 3.4% in length; − 3.3% in perimeter), rounder (− 2.9% circularity and + 4% roundness) but heavier (+ 5%) than the low pCO2 group. Interestingly, there were different effects in males and females; for instance, male cods exposed to high pCO2 exhibited significant changes in circularity (− 3%) and roundness (+ 4%) compared to the low pCO2 males, but without significant changes on otolith dimensions, while females exposed to high pCO2 had smaller otoliths as shown for length (− 5.6%), width (− 2%), perimeter (− 3.5%) and area (− 4.8%). Furthermore, while the majority of the otoliths analysed showed normal aragonite deposition, 10% of fish exposed to 1091µatm of pCO2 had an abnormal accretion of calcite, suggesting a shift on calcium carbonate polymorph crystallization in some individuals under high pCO2 conditions. Our preliminary results indicate that high levels of pCO2 in adult Atlantic cod might affect otolith growth in a gender-specific way. Our findings reveal that otoliths from adult cod are affected by ocean acidification, and we believe that the present study will prompt further research into this currently under-explored area.

Effect of Lime Neutralized Iron Hydroxide Suspensions on Survival, Growth, and Reproduction of the Fathead Minnow (Pimephales promelas)

1973 ◽  
Vol 30 (8) ◽  
pp. 1147-1153 ◽  
Author(s):  
E. J. Smith ◽  
J. L. Sykora ◽  
M. A. Shapiro
Keyword(s):  
Fathead Minnow ◽  
Iron Hydroxide ◽  
Pimephales Promelas ◽  
Iron Concentration ◽  
Fathead Minnows ◽  
Safe Level ◽  
Long Term Effect ◽  
Flow Through ◽  
Growth And Reproduction

The long-term effect of lime neutralized suspended iron on fathead minnow (Pimephales promelas) survival, growth, and reproduction was assessed in a flow-through environment with a modified proportional diluter. Results of 12 months of testing reveal lower survival and declining growth of fathead minnows with an increase in lime neutralized suspended iron concentration. Hatchability and growth of fathead minnows were appreciably reduced in the lowest insoluble iron concentration tested, 1.5 mg Fe/liter. Reduced hatchability was attributed to the higher percentage of smaller particles in low lime neutralized iron concentrations. A comparison of data on survival, growth, and hatchability indicates that the safe level of suspended iron for fathead minnows presumably lies between the control and 1.5 mg Fe/liter.

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