Thermal habitat constraints on zooplankton species associated with Atlantic cod (Gadus morhua) on the US Northeast Continental Shelf

Atlantic cod (Gadus morhua) were collected from six locations on the continental shelf off Newfoundland, Canada, including one inshore area and examined for parasites from 1981 to 1983. The protozoan Loma branchialis was more prevalent in North Atlantic Fisheries Organization (NAFO) areas 3Pn-4R (Gulf of St. Lawrence) and 2J-3K (Labrador), whereas the acanthocephalan Echinorhynchus gadi was more abundant in the latter than in other locations. Similarly, the prevalence and (or) abundance of the fillet-inhabiting larval nematode Pseudoterranova decipiens and the blood-feeding copepod Lernaeocera branchialis were significantly greater in fish from 3Ps (St. Pierre Bank) and 3Pn-4R than from all adjacent areas. Gastrointestinal ascaridoid nematodes were more abundant in 3M (Flemish Cap) cod than in other localities. No differences in the prevalence and abundance of E. gadi were detected in samples in relation to sex or size class. Paired comparisons of transformed data for the different parasite taxa revealed that there were more significant differences than similarities in cod sampled from adjacent NAFO divisions. These observations based on selected parasites (Loma branchialis, Trypanosoma murmanensis, Myxidium gadi, P. decipiens, gastrointestinal ascaridoid nematodes, E. gadi, and Lernaeocera branchialis) support the view that discrete stocks of cod inhabit the Newfoundland–Labrador continental shelf.

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Spatial and temporal abundance patterns for the late stage copepodites of Metridia lucens (Copepoda: Calanoida) in the US northeast continental shelf ecosystem

Journal of Plankton Research ◽

10.1093/plankt/25.2.151 ◽

2003 ◽

Vol 25 (2) ◽

pp. 151-167 ◽

Cited By ~ 8

Author(s):

J. Kane

Keyword(s):

Continental Shelf ◽

Late Stage ◽

Abundance Patterns ◽

The Us ◽

Us Northeast ◽

Temporal Abundance

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Variant colourations of Atlantic cod (Gadus morhua) in Newfoundland and Labrador nearshore waters

ICES Journal of Marine Science ◽

10.1016/j.icesjms.2004.04.003 ◽

2004 ◽

Vol 61 (5) ◽

pp. 752-759 ◽

Cited By ~ 17

Author(s):

Karen R. Gosse ◽

Joseph S. Wroblewski

Keyword(s):

Continental Shelf ◽

Newfoundland And Labrador ◽

Gadus Morhua ◽

Atlantic Cod ◽

Experimental Period ◽

Fish Prey ◽

Northwest Atlantic ◽

Inshore Waters ◽

The Stability

Abstract Adult cod (Gadus morhua) inhabiting continental shelf waters of the Northwest Atlantic typically display a countershaded colouration: a dark back gradating to a light underbelly. Some cod in Newfoundland and Labrador inshore waters have predominantly brown or red pigmentation. Cod inhabiting Gilbert Bay in Labrador often have golden-brown colouration, likely the result of an invertebrate diet rich in carotenoids, and are known in the vernacular as the “golden cod of Labrador”. To determine the stability of these variant colourations, we captured cod from Gilbert Bay, held them in a net pen and fed them a diet of fish. Over the 12-week experimental period, the variant coloured cod lost much of their brown or red pigmentation, and became countershaded. Because of its impermanence when cod switch from invertebrate to fish prey, variant colouration of cod can provide only provisional information about stock origin.

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American lobster dynamics in a brave new ocean

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/cjfas-2013-0094 ◽

2013 ◽

Vol 70 (11) ◽

pp. 1612-1624 ◽

Cited By ~ 42

Author(s):

Robert S. Steneck ◽

Richard A. Wahle

Keyword(s):

North Atlantic ◽

Gadus Morhua ◽

Atlantic Cod ◽

Homarus Americanus ◽

Lifetime Reproductive Success ◽

Larval Size ◽

The North ◽

The Us ◽

The Future ◽

Consequences Of Disease

Dynamic food webs and climate are changing lobster ecology and management. American lobsters (Homarus americanus) evolved in the North Atlantic under conditions of intense predation from large finfish such as Atlantic cod (Gadus morhua). Lobster’s relatively extended brood period and large larval size result in high per capita pelagic phase survival, which, coupled with settlement habitat selection for predator refugia, contributes to the species’ high lifetime reproductive success. However, the western North Atlantic is an extremely low diversity ecosystem prone to booms and busts. Extirpation of coastal predators released past constraints on lobster population growth such that lobster landings increased three- to five-fold since 1980 in Canada and the US. Climate change may stress lobsters in some regions and enhance stocks elsewhere, but it also facilitates warm-water species distribution shift northward. As lobster population densities and water temperatures increase, so do risks and consequences of disease. In the future we must expect the unexpected. “Equilibrium” conditions on which traditional fisheries management depends simply do not exist. This creates new challenges for managing this species regionally and into the future.

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Trophic ecology of Atlantic cod Gadus morhua on the northeast US continental shelf

Marine Ecology Progress Series ◽

10.3354/meps227109 ◽

2002 ◽

Vol 227 ◽

pp. 109-123 ◽

Cited By ~ 109

Author(s):

JS Link ◽

LP Garrison

Keyword(s):

Continental Shelf ◽

Gadus Morhua ◽

Trophic Ecology ◽

Atlantic Cod ◽

Northeast Us

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Geographic Variation in the Spawning of Atlantic Cod, Gadus morhua, in the Northwest Atlantic

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f93-270 ◽

1993 ◽

Vol 50 (11) ◽

pp. 2457-2467 ◽

Cited By ~ 52

Author(s):

Jeffrey A. Hutchings ◽

Ransom A. Myers ◽

George R. Lilly

Keyword(s):

Continental Shelf ◽

Geographic Variation ◽

Relative Abundance ◽

Coastal Waters ◽

Gadus Morhua ◽

Atlantic Cod ◽

Eastern Slope ◽

Northwest Atlantic ◽

Small Section ◽

Eggs And Larvae

We analyzed 47 yr (1946–92) of research trawl data and 5 yr (1964–68) of research gillnet data to identify spawning locations of Atlantic cod, Gadus morhua, in the Newfoundland–Labrador region. Offshore, spawners are common on the continental shelf but generally rare on the slope. Relative abundance of spawning individuals on the shelf is comparably high off northeast Newfoundland, within 100 km of the Newfoundland coast from Cape Freels to Cape Race, on central Grand Bank, and on St. Pierre Bank. Slope spawning is largely restricted to the eastern slope of Hamilton Bank, a small section of northern Grand Bank, and Flemish Cap. Inshore spawning is evident in southeastern Labrador and southeastern Newfoundland, particularly in St. Mary's, Placentia, Trinity, and Bonavista bays. Trajectories of satellite-tracked drifter buoys indicate that it is highly improbable that eggs spawned on the slope of Grand Bank and much of the northeastern Newfoundland slope will be transported into shelf and coastal waters. We conclude that cod spawn in areas in which their eggs and larvae are likely to be retained and that inshore spawning populations may provide a considerably larger contribution to cod recruitment in coastal Newfoundland than has previously been believed.

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