Antifreeze Production, Freeze Resistance, and Overwintering of Juvenile Northern Atlantic Cod (Gadus morhua)

1992 ◽  
Vol 49 (3) ◽  
pp. 516-522 ◽  
Author(s):  
Sally V. Goddard ◽  
Ming H. Kao ◽  
Garth L. Fletcher
Keyword(s):  
Gadus Morhua ◽  
Atlantic Cod ◽  
Fish Length ◽  
Antifreeze Glycoproteins ◽  
Freeze Resistance ◽  
Ambient Temperatures ◽  
Temperature Regimes ◽  
Northern Atlantic ◽  
Freezing Temperatures ◽  
Cycling Temperature

Four size groups of northern Atlantic cod (Gadus morhua) (juveniles < 15, 15–25, and 26–40 cm and adults > 50 cm) were investigated over a winter cycle for their ability to increase freeze resistance by producing plasma antifreeze glycoproteins. All juveniles had significantly higher plasma antifreeze levels than adults during the winter (January–March) under similar conditions of cycling temperature and ambient photoperiod. Highest winter plasma antifreeze levels and lowest plasma freezing temperatures were consistently found in the 15–25 cm group. Fish length and plasma antifreeze levels were inversely related from January to April, with the exception of the 0 + cod. All juvenile groups developed considerable freeze protection early in the winter cycle before the onset of freezing temperatures. However, the adults were not significantly protected until the end of January, when ambient temperatures had fallen below 0 °C. The 15–25 cm cod were held in three cycling temperature regimes. Induction temperatures for antifreeze production in this size group appeared to be between 2 and 3 °C, as compared with between 1 and 0 °C for the adults. We suggest that these patterns of antifreeze production may have direct bearing on habitat selection and overwintering behaviour of the northern Atlantic cod at different stages of development.

Survival of Northern Atlantic Cod (Gadus morhua) Eggs and Larvae when Exposed to Ice and Low Temperature

1992 ◽  
Vol 49 (12) ◽  
pp. 2588-2595 ◽  
Author(s):  
Paul F. Valerio ◽  
Sally V. Goddard ◽  
Ming H. Kao ◽  
Garth L. Fletcher
Keyword(s):  
Low Temperature ◽  
Newfoundland And Labrador ◽  
Direct Contact ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Ice Crystals ◽  
Freeze Resistance ◽  
Northern Cod ◽  
Northern Atlantic ◽  
Eggs And Larvae

Freeze resistance of eggs and larvae of Atlantic cod (Gadus morhua) from the northern cod stock was investigated to determine whether ice contact could affect survival during the spring spawning season off Newfoundland. Egg and larval homogenates did not appear to contain antifreeze proteins (mean freezing points −0.78 and −0.88 °C, respectively). However, cod eggs did not freeze at −1.8 °C in icy aerated seawater, could be undercooled to −4.0 °C in ice, and froze at temperatures between −4.1 and −1 7 °C; freeze resistance depended on the integrity of the chorion. Larvae withstood undercooling to −1.8 °C, provided they were not brought into direct contact with ice crystals, if directly touched with ice, larvae froze at −1.36 °C (feeding stage) or −1.34 °C (yolk-sac), approximately 0.5 °C lower than would be expected from the freezing temperatures of their body fluids. The nature of their external epithelium and delayed development of sensitive gill structures below 0 °C may contribute to larval freeze resistance. Cod eggs and larvae are found in spring off Newfoundland and Labrador, when sea temperatures can be as low as −1.8 °C and ice cover extensive. While cod eggs are remarkably freeze resistant, such environmental conditions may cause freezing mortalities in larval cod.

Isolation or metapopulation: whence and whither the Smith Sound cod?

2011 ◽  
Vol 68 (1) ◽  
pp. 152-169 ◽  
Author(s):  
George A. Rose ◽  
R. John Nelson ◽  
Luiz G.S. Mello
Keyword(s):  
Gadus Morhua ◽  
Atlantic Cod ◽  
Genetic Data ◽  
Spawning Aggregation ◽  
Genetic Isolation ◽  
Coastal Fisheries ◽  
Data History ◽  
Northern Atlantic ◽  
First Maturity ◽  
Year 2000

In April 1995, a spawning aggregation of “northern” Atlantic cod ( Gadus morhua ) (10 000 t) appeared in Smith Sound, Newfoundland, growing to 26 000 t by year 2000. The origin of the founder year classes (primarily the 1990 and 1992 year classes) and potential for expansion remains controversial, with genetic isolation used to justify reopenings of coastal fisheries. We investigated the origin using historical, demographic, and genetic data. History provided no evidence of large aggregations before 1995. Demographics in the early 1990s suggested few spawners in Smith Sound, but many in the adjacent Bonavista Corridor. The strong 1990 year class was not evident until 1995 and the strong 1992 year class until 1997 (both age 5 and first maturity). Genetic study of six microsatellite loci from 791 cod from overwintering aggregations in Smith Sound and offshore regions indicated little to no differentiation (FST) among southern groups (Smith Sound, Bonavista Corridor, Halibut Channel). These results provide a perspective that these groups comprise a metapopulation and that the Smith Sound aggregation arose not from self-recruitment but immigration. By 2009, the aggregation had dispersed, with large concurrent increases in the Bonavista Corridor.

Seasonal changes in the plasma levels of glycoprotein antifreeze, Na+, Cl−, and glucose in Newfoundland Atlantic cod (Gadus morhua)

1982 ◽  
Vol 60 (8) ◽  
pp. 1851-1854 ◽  
Author(s):  
G. L. Fletcher ◽  
D. Slaughter ◽  
C. L. Hew
Keyword(s):  
Seasonal Changes ◽  
Gadus Morhua ◽  
Thermal Hysteresis ◽  
Atlantic Cod ◽  
Freezing Point ◽  
Freezing Point Depression ◽  
Antifreeze Glycoproteins ◽  
Glucose Levels ◽  
Total Plasma Protein ◽  
Two Peaks

A seasonal study was carried out on the hematocrits, plasma freezing point depression, and thermal hysteresis, and plasma Na+, Cl−, total protein, and glucose concentrations in laboratory maintained Atlantic cod. Significant thermal hysteresis was evident in the plasma during the months of January to May indicating the presence of antifreeze glycoproteins. Plasma freezing point depression and Na+ and Cl− concentrations were highest during the winter months and lowest during the summer. Two peaks in glucose levels were evident; one in February and the other in July. No seasonal changes were evident in hematocrits and total plasma protein concentrations.

Back-Calculated Fish Lengths and Hg and Zn Levels from Recent and 100-Yr-Old Cleithrum Bones from Atlantic Cod (Gadus morhua)

1977 ◽  
Vol 34 (1) ◽  
pp. 147-150 ◽  
Author(s):  
J. S. Scott
Keyword(s):  
Gadus Morhua ◽  
Atlantic Cod ◽  
Fish Length ◽  
Zinc Levels

Dimensions of cleithrum bones from recently caught Atlantic cod (Gadus morhua) were measured and plotted against observed fish lengths to back-calculate cod lengths from cleithra from a ship wrecked in 1865. Mercury levels in the historical bones were approximately the same as those in recent material and showed no increase with fish length, but zinc levels appearto have increased since 1865 and increased with fish length.

Factors affecting the swimming endurance and catchability of Atlantic cod (Gadus morhua)

2000 ◽  
Vol 57 (6) ◽  
pp. 1200-1207 ◽  
Author(s):  
Paul D Winger ◽  
Pingguo He ◽  
Stephen J Walsh
Keyword(s):  
Swimming Speed ◽  
Newfoundland And Labrador ◽  
Gadus Morhua ◽  
Failure Time ◽  
Atlantic Cod ◽  
Fish Length ◽  
Time Analysis ◽  
Factors Affecting ◽  
Highly Sensitive ◽  
Swimming Endurance

The swimming endurance of Atlantic cod (Gadus morhua), native to the cold waters off the east coast of Newfoundland and Labrador, was investigated under laboratory conditions. Using a swimming flume, endurance was tested at swimming speeds ranging from 0.6 to 1.3 m·s-1 using water temperatures from 0.0 to 9.8°C ( mean = 3.2°C, SD = 2.8) and fish lengths from 41.0 to 86.0 cm ( mean = 57.8 cm, SD = 10.5). The results revealed that swimming speed was the only significant factor affecting the endurance of cod. The maximum sustained swimming speed (Ums) was predicted to be 0.66 m·s-1. Statistical analysis of the data was conducted using failure time analysis. The hazard, or risk of exhaustion, was found to increase rapidly with increasing swimming speed, i.e., there was a decrease in the probability of cod achieving a given swimming endurance. Probability curves for the endurance of cod were calculated for different swimming speeds. The findings suggest that the catching efficiency of commercially targeted cod (>41.0 cm) by otter trawls may be highly sensitive to changes in towing speed while being independent of both fish length and water temperature.

Antifreeze glycoproteins in the plasma of Newfoundland Atlantic cod (Gadus morhua)

1981 ◽  
Vol 59 (11) ◽  
pp. 2186-2192 ◽  
Author(s):  
Choy L. Hew ◽  
Don Slaughter ◽  
Garth L. Fletcher ◽  
Shashikant B. Joshi
Keyword(s):  
Amino Acid ◽  
High Performance ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Antifreeze Proteins ◽  
Gel Filtration ◽  
Exchange Chromatography ◽  
Polar Cod ◽  
Antifreeze Glycoproteins ◽  
Molecular Weights

The plasma of the Atlantic cod, Gadus morhua, contained antifreeze glycoproteins which were present only during the winter months. The antifreeze proteins were isolated, using gel filtration and ion exchange chromatography, and characterized by high performance liquid chromatography. The antifreeze proteins appeared to consist of at least seven components with molecular weights ranging from 2 500 to 33 000. Chemical analysis of the larger components showed a predominance of alanine, threonine, and galactosamine in a ratio of 2:1:1. The smaller peptides contained proline, in addition to alanine and threonine. The amino acid sequence of the smallest glycopeptide (molecular weight 2500) was found to be Ala Ala Thr Pro Ala Thr Ala Ala Thr Pro Ala Thr Ala Ala.These glycoproteins are very similar, if not identical, in amino acid and carbohydrate composition to those isolated from Antaractic nototheniids and several northern gadoids. The sequence of the smallest glycopeptide from the Atlantic cod is identical to that reported for the polar cod, Boreogadus saida.

scholarly journals Methods and results of in situ target-strength measurements of Atlantic cod (Gadus morhua) during combined trawl-acoustic surveys

2009 ◽  
Vol 66 (6) ◽  
pp. 1225-1232 ◽  
Author(s):  
Viacheslav A. Ermolchev
Keyword(s):  
Gadus Morhua ◽  
Barents Sea ◽  
Atlantic Cod ◽  
Biological Data ◽  
Target Strength ◽  
Fish Length ◽  
The Barents Sea ◽  
Total Fish ◽  
Acoustic Surveys

Abstract Ermolchev, V. A., 2009. Methods and results of in situ target-strength measurements of Atlantic cod (Gadus morhua) during combined trawl-acoustic surveys. – ICES Journal of Marine Science, 66: 1225–1232. This paper presents methods for collecting acoustic and biological data, including in situ target-strength (TS) estimates of fish, with results presented for Atlantic cod (Gadus morhua) obtained from combined trawl-acoustic surveys. These include fish in the small, average, and maximum length classes, within the range 5–136 cm (total fish length, LT). The investigations were done using Simrad EK500/EK60 echosounders with split-beam transducers and special post-processing software. Based on an analysis of data collected in the Barents Sea during 1998–2007, a relationship TS = 25.2 log10(LT) − 74.8 was obtained for Atlantic cod at 38 kHz, with TS in dB and LT in centimetres. Seasonally, and for depths between 50 and 500 m, the variability in cod TS was 3.1 dB, decreasing with depth. The largest day–night difference in mean TS was in August–September, with changes as large as 1.0–1.7 dB. In the other seasons, the day–night difference was <1.0 dB.

Cods for sale Do we know what we are buying?

DNA Barcodes ◽  
2015 ◽  
Vol 3 (1) ◽  
Author(s):  
Christian Lambarri ◽  
Héctor Espinosa ◽  
Armando Martínez ◽  
Ariana Hernández
Keyword(s):  
Gadus Morhua ◽  
Atlantic Cod ◽  
The United States ◽  
High Rate ◽  
Coi Gene ◽  
High Price ◽  
Blue Shark ◽  
Salted Fish ◽  
Northern Atlantic ◽  
Near Threatened

AbstractThe Atlantic Cod Gadus morhua is fished in Northern Atlantic and Arctic waters. In Mexico cod is imported from Norway and the United States, and is traditionally eaten at Christmas and Easter. In Mexico City several stores sell dry-salted cod, but due to the high price of the imported Atlantic Cod, other fish species are sold. In this project we examined six samples of dried-salted fish from different stores and used DNA barcoding of the COI gene to corroborate the identity of the product sold as Atlantic Cod. Barcoding revealed that only two of the six samples (33%) were Atlantic cod, with two being Ling, one Alaska Pollock, and one Blue Shark. The high rate of mislabeling (67%) is a major concern. It is especially worrying that Blue Shark is being sold as Atlantic cod, since the Blue Shark is listed as a near-threatened species by the IUCN. We must be aware of the damages that overexploitation and uninformed consumption cause to cod and shark populations. There needs to be stricter policing of seafood product labeling in México.

Sign in / Sign up

Export Citation Format

Share Document