Age, Growth and Sexual Maturity of Cod (Gadus morhua L.) in the Newfoundland Area, 1947–1950

1960 ◽  
Vol 17 (6) ◽  
pp. 775-809 ◽  
Author(s):  
A. M. Fleming
Keyword(s):  
Growth Rate ◽  
West Coast ◽  
Sexual Maturity ◽  
Gadus Morhua ◽  
East Coast ◽  
Age Groups ◽  
Early Summer ◽  
Growth Data ◽  
Southwestern Part ◽  
Northeastern Part

Samples of cod were collected from fishing gears in the coastal areas of Newfoundland and Labrador and from research otter-trawlers on the neighbouring banks from 1947 to 1950. Collections for the most part were from early summer to early autumn. Ages were determined using otoliths. Calculations of growth were based on average lengths and weights of the different age-groups in the samples.The growth rates of cod from various parts of the area were found to differ widely. Labrador cod had the slowest growth rate, much slower than cod from other parts of the area. Cod from the east coast of Newfoundland and the northeastern part of the Grand Bank were also slow-growing. Cod from the southwestern part of the Grand Bank had the fastest growth rate. Though cod from St. Pierre Bank and southwestern Newfoundland were fast-growing, also, they exhibited a somewhat slower growth rate than those from the southwestern part of the Grand Bank. Cod from the west coast of Newfoundland grew faster than cod from the east coast, but slower than those from southwestern Newfoundland.Though differences in growth rate were small between the sexes, the females generally grew at a slightly faster rate.The influence of differences in temperature and in food supply on the growth of cod in the area is discussed.Comparable growth data for the area published by several investigators are discussed. It is suggested that differences in these data were the result of variation in sampling locality, different sampling gears, different combination of individual samples and differences in age estimation.Both the size and age at which all fish were sexually mature varied throughout the area of investigation. Labrador cod matured at an earlier age and smaller size than cod from other parts of the area, whereas cod from the southwestern part of the Grand Bank generally matured at a later age and larger size than cod from other parts of the area. Cod from the east coast of Newfoundland, the northeastern part of the Grand Bank, St. Pierre Bank and the southwest and west coasts of Newfoundland were intermediate between cod from Labrador and the southwestern part of the Grand Bank in age and size at maturity, fish from the east coast generally maturing at an earlier age and smaller size than fish to the south on the Grand Bank and St. Pierre Bank and from the southwest and west coasts.The age, growth and sexual maturity relationships of cod from various parts of the area, when analyzed in the light of tagging experiments, meristic studies, parasite studies and hydrographic information, suggest the existence of at least four relatively distinct divisions in the cod population of the area, between which there is only limited intermingling. These are the Labrador, the Newfoundland east coast, the southern Grand Bank and the Newfoundland west coast divisions, with areas such as St. Pierre Bank and the Strait of Belle Isle being mixing areas of cod from adjacent divisions.

Infection of Lumpfish (Cyclopterus lumpus) with Larvae and of Atlantic cod (Gadus morhua) with Adults of the Copepod, Lernaeocera branchialis, in and adjacent to the Newfoundland area, and Inferences Therefrom on Inshore–Offshore Migrations of Cod

1976 ◽  
Vol 33 (4) ◽  
pp. 711-731 ◽  
Author(s):  
Wilfred Templeman ◽  
V. M. Hodder ◽  
A. M. Fleming
Keyword(s):  
Intermediate Host ◽  
West Coast ◽  
Gadus Morhua ◽  
East Coast ◽  
Atlantic Cod ◽  
Adult Parasite ◽  
Infection Rates ◽  
The West ◽  
Cyclopterus Lumpus ◽  
Branchial Arches

The lumpfish, Cyclopterus lumpus, was found to be a common intermediate host of the larvae of the copepod, Lernaeocera branchialis, in the Newfoundland and neighboring areas. Large numbers of these larvae occurred on the gills of lumpfish from inshore Newfoundland areas from the latter half of June to the first half of August, whereas only minor infection was found in any month in offshore areas. Some larvae of the year reached the final or seventh stage on the intermediate host in May on the west coast of Newfoundland and in June on the east coast. By July on the west coast and early August on the east coast, this was by far the most numerous stage present. The larvae were attached mainly near the tips of the gill filaments. Most larvae were attached to the gills of the first two branchial arches, less to those of the third, and much less to those of the fourth. There were more larvae on the right than on the left gills. Infection of the final host Atlantic cod (Gadus morhua), by stage-7 female L. branchialis was apparently mainly inshore.Adult L. branchialis on Atlantic cod, typically located near the anterior ventral apex of the branchial arches, were numerous throughout the year in the areas of high infection. Infection rates of cod with the adult parasite were usually considerably higher near the coast than farther offshore, the rates declining with distance from the coast. Rates of infection with the adult parasite usually increased from the smaller to intermediate cod lengths and declined rapidly at greater lengths. Infection rates were found useful as evidence of inshore and offshore migrations of cod. Infection with the copepod apparently delayed sexual maturity in cod. Most infected cod (86%) had one adult copepod and declining numbers (12–0.05%) possessed two to five adult copepods. The Greenland cod, G. ogac, was the only other fish of the area found to be highly infected with adult L. branchialis.

scholarly journals Growth analysis of chub, Leuciscus cephalus (L.), and dace, Leuciscus leuciscus (L.), in the Úpoř stream using growth data of recaptured marked fish

2011 ◽  
Vol 50 (No. 7) ◽  
pp. 329-339 ◽  
Author(s):  
P. Vlach ◽  
J. Dušek ◽  
M. Švátora ◽  
P. Moravec
Keyword(s):  
Growth Rate ◽  
Age Groups ◽  
Growth Equation ◽  
Growth Data ◽  
Average Value ◽  
Slowing Down ◽  
Length Growth ◽  
Weight Relationship ◽  
Average Condition ◽  
The Mean

The length growth of chub and dace was observed. The scale method was used as well as data gained from recaptured individuals which were marked with visible elastomer tags and platinum wire tags with a coloured code placed under the first bony ray of the dorsal fin. The length-weight relationship for chub could be explained by the equation w = 0.00001.l <sup>3.067</sup> (r<sup>2</sup> = 0.96). The average condition coefficient reached 1.49. The growth was balanced, gradually slowing down. Von Bertallanffy growth equation had the form L<sub>t </sub>= 245.47(1 &ndash; e<sup>&ndash;0.206(t + 0.0333)</sup>). The average value of instantaneous monthly growth rate (G<sub>m</sub>) ranged between 0.4 and 4.3 (in %). Mean G<sub>m</sub> of particular age groups gradually decreased. G<sub>m</sub> varied seasonally, annually and in different parts of the stream. The length-weight relationship for dace was w = 0.000009.1<sup>3.0948 </sup>(r<sup>2</sup> = 0.97). The mean condition coefficient reached the value of 1.11. The length growth was balanced, gradually decreasing. Von Bertallanffy equation had the form L<sub>t</sub> = 216.28(1 &ndash; e<sup>&ndash;0.2536(t + 0.26094)</sup>). The instantaneous monthly growth rate ranged between &ndash;1.57 and 10.38 (in percentage). This indicator fluctuated according to the age, season and year. &nbsp;

Inuit-European Interactions in Greenland

2016 ◽  
Author(s):  
Hans-Christian Gulløv
Keyword(s):  
Nineteenth Century ◽  
Eighteenth Century ◽  
Sixteenth Century ◽  
Middle Ages ◽  
West Coast ◽  
East Coast ◽  
The West ◽  
Southwestern Part ◽  
West Greenland ◽  
The Middle Ages

In every century since the Middle Ages there have been Europeans in Greenland. Medieval Norse farmers settled in the southwestern part of the country and met with Native Greenlanders from the twelfth to the fifteenth centuries. From the sixteenth century onward, English and Danish explorers, followed by primarily Dutch whalers, met the Inuit on the west coast of Greenland. In 1721, Greenland was colonized from the double monarchy Denmark-Norway. During the eighteenth century, permanent settlements were established throughout west Greenland, and in the nineteenth century contacts were established with the Inuit on the east coast and in the Thule area.

Migrations and Intermingling of Atlantic Cod (Gadus morhua) Stocks of the Newfoundland Area

1974 ◽  
Vol 31 (6) ◽  
pp. 1073-1092 ◽  
Author(s):  
Wilfred Templeman
Keyword(s):  
Gadus Morhua ◽  
East Coast ◽  
Atlantic Cod ◽  
Late Summer ◽  
Early Spring ◽  
Early Summer ◽  
Southeastern Part ◽  
Vertical Movements ◽  
Bank Stock ◽  
Avalon Peninsula

Commercial recaptures of 26% (22.5% in years after the tagging year) of 18,822 Atlantic cod (Gadus morhua) 50 cm or more in length that were tagged mainly in the feeding season at 13 localities in the Newfoundland area in 1954–55 elucidated migrations and intermingling of cod of various stocks or stock complexes. Cod of the northern Gulf of St. Lawrence stock migrated southward from the Strait of Belle Isle to winter on the northern side of Cabot Strait and vicinity, mingling there with the Burgeo Bank stock. Cod of the Newfoundland–Labrador complex tagged at three sites mingled along the east coast of Newfoundland and off southern Labrador and with cod of the northern Gulf stock near the Strait of Belle Isle, of the Avalon–Burin stock complex off the Avalon peninsula, and of a Grand Bank stock on the northern part of the bank. Though cod tagged off the Avalon peninsula and on St. Pierre Bank were recaptured mainly near the tagging sites, some moved as far north as Labrador, to the southern Grand Bank, and to Cabot Strait. Fish tagged on the northwestern Grand Bank were recaptured mainly at the tagging site but also elsewhere on the bank and off the east coast of Newfoundland. Those tagged on the Southeast Shoal of the Grand Bank were recaptured mainly on the southeastern part of the bank though some moved as far as southeastern Newfoundland. Those tagged on Burgeo Bank mingled with the Avalon–Burin stock complex, including the St. Pierre Bank component, but mainly with the Northern Gulf stock in winter–spring near Cabot Strait.Cod 90–129 cm long at tagging were recaptured at shorter distances from the tagging sites than 50–89-cm cod. Tagging–recapture distances also increased with increasing age for cod of the smaller length ranges on tagging. In their vertical movements, most tagged cod moved to shallow water in late spring or early summer and retreated gradually to deeper water from late summer to early spring. Some remained in deep water throughout the year.Recapture rates at different size ranges varied with area but were not greatly different at length ranges from 50–59 to 80–94 cm, which included 95% of the tagged cod.

Natural mortality from poor condition in Atlantic cod (Gadus morhua)

2000 ◽  
Vol 57 (4) ◽  
pp. 826-836 ◽  
Author(s):  
Jean-Denis Dutil ◽  
Yvan Lambert
Keyword(s):  
Gadus Morhua ◽  
Atlantic Cod ◽  
Negative Impact ◽  
Fish Muscle ◽  
Early Summer ◽  
Wild Fish ◽  
Natural Mortality ◽  
Muscle Lactate ◽  
Lactate Dehydrogenase Activity ◽  
Poor Condition

The extent of energy depletion was assessed in Atlantic cod (Gadus morhua) in spring and early summer (1993-1995) to assess relationships between poor condition and natural mortality. Several indices of condition were compared in wild fish in the northern Gulf of St. Lawrence and in fish exposed to a prolonged period of starvation in laboratory experiments. Discriminant analyses classified only a small fraction of the wild fish as similar to cod that did not survive and a much larger fraction as similar to cod that survived starvation. This percentage increased from April to May and peaked in June 1993 and 1994. Condition factor and muscle somatic index allowed a clear distinction between live and dead fish. Muscle lactate dehydrogenase activity suggested that cod had experienced a period of negative growth early in 1993, 1994, and 1995. Fish classified as similar to starved individuals were characterized by a higher gonad to liver mass ratio than others. Reproduction may have a negative impact on survival not only in spring but also later into summer, as some individuals were found not to have recovered by late summer. This study shows that natural mortality from poor condition contributed to lower production in the early 1990s.

Using a GLMM to estimate the somatic growth rate trend for male South African west coast rock lobster, Jasus lalandii

2004 ◽  
Vol 70 (2-3) ◽  
pp. 339-349 ◽  
Author(s):  
A. Brandão ◽  
D.S. Butterworth ◽  
S.J. Johnston ◽  
J.P. Glazer
Keyword(s):  
Growth Rate ◽  
South African ◽  
West Coast ◽  
Somatic Growth ◽  
Rock Lobster ◽  
Somatic Growth Rate

scholarly journals ENSO and Wintertime Extreme Precipitation Events over the Contiguous United States

2008 ◽  
Vol 21 (1) ◽  
pp. 22-39 ◽  
Author(s):  
Siegfried D. Schubert ◽  
Yehui Chang ◽  
Max J. Suarez ◽  
Philip J. Pegion
Keyword(s):  
United States ◽  
West Coast ◽  
Extreme Precipitation ◽  
East Coast ◽  
Daily Precipitation ◽  
Precipitation Variability ◽  
The West ◽  
Extreme Precipitation Events ◽  
The Impact ◽  
Precipitation Events

Abstract In this study the authors examine the impact of El Niño–Southern Oscillation (ENSO) on precipitation events over the continental United States using 49 winters (1949/50–1997/98) of daily precipitation observations and NCEP–NCAR reanalyses. The results are compared with those from an ensemble of nine atmospheric general circulation model (AGCM) simulations forced with observed SST for the same time period. Empirical orthogonal functions (EOFs) of the daily precipitation fields together with compositing techniques are used to identify and characterize the weather systems that dominate the winter precipitation variability. The time series of the principal components (PCs) associated with the leading EOFs are analyzed using generalized extreme value (GEV) distributions to quantify the impact of ENSO on the intensity of extreme precipitation events. The six leading EOFs of the observations are associated with major winter storm systems and account for more than 50% of the daily precipitation variability along the West Coast and over much of the eastern part of the country. Two of the leading EOFs (designated GC for Gulf Coast and EC for East Coast) together represent cyclones that develop in the Gulf of Mexico and occasionally move and/or redevelop along the East Coast producing large amounts of precipitation over much of the southern and eastern United States. Three of the leading EOFs represent storms that hit different sections of the West Coast (designated SW for Southwest coast, WC for the central West Coast, and NW for northwest coast), while another represents storms that affect the Midwest (designated by MW). The winter maxima of several of the leading PCs are significantly impacted by ENSO such that extreme GC, EC, and SW storms that occur on average only once every 20 years (20-yr storms) would occur on average in half that time under sustained El Niño conditions. In contrast, under La Niña conditions, 20-yr GC and EC storms would occur on average about once in 30 years, while there is little impact of La Niña on the intensity of the SW storms. The leading EOFs from the model simulations and their connections to ENSO are for the most part quite realistic. The model, in particular, does very well in simulating the impact of ENSO on the intensity of EC and GC storms. The main model discrepancies are the lack of SW storms and an overall underestimate of the daily precipitation variance.

Effect of Hardness and Tensile Mean Stress on Fatigue Crack Growth in Beryllium Copper

1969 ◽  
Vol 11 (3) ◽  
pp. 343-349 ◽  
Author(s):  
L. P. Pook
Keyword(s):  
Growth Rate ◽  
Fatigue Crack ◽  
Crack Growth Rate ◽  
Fatigue Crack Growth ◽  
Residual Stresses ◽  
Crack Growth ◽  
Fatigue Crack Growth Rate ◽  
Mean Stress ◽  
Growth Data ◽  
Beryllium Copper

Some fatigue crack growth data have been obtained for age-hardened beryllium copper. The fatigue crack growth rate was found to be very dependent on the hardness and tensile mean stress. This dependence is believed to be associated with the intense residual stresses surrounding Preston-Guinier zones.

Influence of climatic changes on the parasites of Atlantic cod Gadus morhua off coastal Labrador, Canada

2006 ◽  
Vol 80 (2) ◽  
pp. 193-197 ◽  
Author(s):  
R.A. Khan ◽  
C.V. Chandra
Keyword(s):  
North Atlantic ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Age Groups ◽  
Climatic Conditions ◽  
Otter Trawl ◽  
Commercial Fishery ◽  
Metazoan Parasites ◽  
Mean Values ◽  
The North

AbstractA study was conducted in 2000 and 2003, following the collapse of the commercial fishery in 1990, to compare metazoan parasites of Atlantic cod Gadus morhua, captured off coastal Labrador, with samples taken in 1980 and 1986. Fish were captured by otter trawl offshore in the North Atlantic Fish Organisation subarea 2J. Parasites were removed from the digestive tract, stained, identified and compared between the different groups. Both the prevalence and mean abundance of trematodes, larval nematodes and E. gadi were significantly lower in fish taken in 2000 and 2003 than in 1980. While mean values of trematodes and nematodes declined in 1986, those of Echinorhynchus gadi remained unchanged in 1986 and 1990. Four-year-old cod sampled in 1990 harboured significantly fewer E. gadi than older age groups. The most commonly occurring trematodes included Podocotylereflexa, Lepidapedon elongatum, Derogenes varicus and Hemiurus levinseni while the larval nematode, Anisakis sp. was predominant. Comparison of offshore samples taken in 2000 and 2003 with others taken in previous years suggests an overall decline of parasites coincident with a change in climatic conditions, the absence of a major food source, namely capelin Mallotus villosus, of cod and ultimately the decline of the Labrador population.

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