Atlantic Cod Populations along the Southern Canadian Mainland as shown by Vertebral Count Studies

R. A. McKenzie; G. F. M. Smith

doi:10.1139/f55-037

Atlantic Cod Populations along the Southern Canadian Mainland as shown by Vertebral Count Studies

Journal of the Fisheries Research Board of Canada ◽

10.1139/f55-037 ◽

1955 ◽

Vol 12 (5) ◽

pp. 698-705 ◽

Cited By ~ 6

Author(s):

R. A. McKenzie ◽

G. F. M. Smith

Keyword(s):

Nova Scotia ◽

Atlantic Cod ◽

South Coast ◽

The South ◽

Vertebral Number ◽

Vertebral Count ◽

Seasonal Migrations

Analysis of vertebral counts of 28,097 cod (Gadus callarias L.) in 184 samples from the Canadian mainland coast demonstrates some segregation of inshore and offshore populations and little mixing between the cod on various sections of the coast. Four populations are recognized in the Gulf of St. Lawrence. Three offshore populations and at least four inshore populations are also recognized along the south coast of Nova Scotia. Seasonal migrations northward in summer and southward in winter are indicated by changes in vertebral numbers. Small cod (less than 21/2 lb.) exhibit less variability in vertebral number than larger ones, suggesting increased mixing with growth.

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The Effect of a Storm on an Inshore Area with Markedly Stratified Waters

Journal of the Biological Board of Canada ◽

10.1139/f35-007 ◽

1935 ◽

Vol 1 (4) ◽

pp. 227-237 ◽

Cited By ~ 7

Author(s):

H. B. Hachey

Keyword(s):

Nova Scotia ◽

North Atlantic ◽

Surface Waters ◽

South Coast ◽

The South ◽

Wind Action ◽

Bottom Waters ◽

Mixed Water

Coincident with the formation and subsequent movement of a North Atlantic cyclone following the characteristic track, offshore surface waters are forced to the south coast of Nova Scotia with consequent removal of intermediate and bottom waters. Wind action, as the storm approaches, intensifies the mixing of the waters. Markedly stratified waters are thus temporarily replaced by a body of thoroughly mixed water.

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Larval Anisakis simplex (Nematoda: Ascaridoidea) Infection in the Musculature of Atlantic Cod, Gadus morhua, from Newfoundland and Labrador

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f92-292 ◽

1992 ◽

Vol 49 (12) ◽

pp. 2635-2647 ◽

Cited By ~ 15

Author(s):

John Brattey ◽

Claude A. Bishop

Keyword(s):

Newfoundland And Labrador ◽

Gadus Morhua ◽

Atlantic Cod ◽

Body Cavity ◽

The Body ◽

Anisakis Simplex ◽

South Coast ◽

The South ◽

Eastern Canada ◽

Examination Method

Larvae of Anisakis simplex were found in the flesh of Atlantic cod, Gadus morhua, collected in 21 regions around Newfoundland and Labrador during 1985–87. Prevalence and abundance increased with cod size and varied geographically; cod off Labrador had the fewest larvae whereas those from the south coast of Newfoundland were the most heavily infected. Most larvae (~95%) occurred in flesh surrounding the body cavity (napes), with a significantly higher percentage of the nematodes (~58%) in the flesh on the left side. In 505 cod in which all tissues were examined, 85.6, 10.8, and 3.5% of the A. simplex resided in the body cavity and viscera, napes, and fillets, respectively. Cod surveyed tended to have more A. simplex in the musculature than those from other areas off eastern Canada, but are lightly infected compared with most other Atlantic cod stocks. The examination method (candling combined with slicing) recovered, on average, 42% of the A. simplex present in the flesh; consequently, infection statistics reported here are underestimates. Numbers of A. simplex in cod off Labrador and eastern Newfoundland are similar to those observed during 1947–53, but the abundance of A. simplex appears to have increased among cod from NAFO Subdivision 3Pn.

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Prevalence of a Trypanosome in Atlantic Cod (Gadus morhua) Especially in Relation to Stocks in the Newfoundland Area

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f80-190 ◽

1980 ◽

Vol 37 (10) ◽

pp. 1467-1475 ◽

Cited By ~ 18

Author(s):

R. A. Khan ◽

J. Murphy ◽

D. Taylor

Keyword(s):

Gadus Morhua ◽

Atlantic Cod ◽

South Coast ◽

The South ◽

High Prevalence ◽

Management And Conservation

A study was initiated to ascertain the prevalence of a trypanosome in Atlantic cod (Gadus morhua) especially in relation to stocks in the Newfoundland area and as an aid in management and conservation. Highest prevalences were recorded in fish taken off the Labrador coast (ICNAF divisions 2J and 3K, 94 and 90%, respectively). Trypanosomes were not as prevalent in fish collected from the northern Grand Bank (46%, division 3L) or from the southern Grand Bank (13 and 16%, divisions 3N and 3O, respectively). A further decrease in prevalence occurred among fish collected on the Flemish Cap (10%,, division 3M) and St. Pierre Bank (8%, subdivision 3Ps), while the lowest levels (4%) were apparent in cod taken from the Gulf of St. Lawrence (divisions 4R and 4S). Fish sampled at inshore localities reflected prevalences corresponding to some extent to offshore localities. Cod taken on coastal Labrador and from northern Newfoundland have a high prevalence of trypanosome infections while in the more easterly bays, intermediate levels occur. A conspicuous decrease in prevalence was apparent in a sample taken from the most easterly inshore locality (Portugal Cove) and from two others on the south coast of Newfoundland. Lowest prevalences were noted among fish taken at four inshore localities in the Gulf of St. Lawrence. These results, based on prevalences of infection, support conclusions from other studies that there are at least six stocks of cod in the Newfoundland area with some degree of mixing.Key words: trypanosome, prevalence, cod stocks, Newfoundland–Labrador, ICNAF

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