Surface Circulation Pattern in the Gulf of St. Lawrence

El‐Sabh, M. I.

doi:10.1139/f76-015

Cited by 79 publications

(39 citation statements)

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“…These aggregations, mainly consisting of Meganyctiphanes norvegica and Thysanoessa raschi (Simard et al 1986a), attract populations of fishes and marine mammals (de Lafontaine et al 1991, Kingsley & Reeves 1998. The system is dominated by a strong seasonal cycle of the general circulation (El-Sabh 1976, Mertz et al 1991, Saucier et al 2003 and high interannual variability (e.g. Gilbert & Pettigrew 1997).…”

Section: Introductionmentioning

confidence: 99%

Krill aggregation in the St. Lawrence system, and supply of krill to the whale feeding grounds in the estuary from the gulf

Sourisseau¹,

Simard²,

Saucier³

2006

Mar. Ecol. Prog. Ser.

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Persistent high-density krill aggregations make the St. Lawrence Estuary and the Gulf of St. Lawrence important feeding-grounds for large marine mammals. To estimate the effects of the circulation on the seasonal krill distribution, a krill biomass-concentration equation with active vertical migration was coupled to a 3D regional sea ice-ocean circulation model. The results show recurrent spatial patterns of aggregation and advection controlled by the circulation and a high sensitivity to the parameters of the biological model. The time spent in the surface layer is crucial for the retention of organisms in the estuary. The simulated krill aggregation areas are associated with 3 processes (tidal interactions with bathymetry, wind-driven upwelling and mean circulation). Zooplankton generally aggregate near the edges of the Laurentian Channel and other secondary channels, at locations that are consistent with the sparse synoptic information on the distributions of large marine mammals in the gulf. The simulations also indicate that changes in the seasonal circulation significantly affect the krill distribution within the gulf through gyre intensities, the seasonal thermocline and the strength of the estuarine circulation. Finally, the variability of zooplankton transport to the estuary from the gulf appears to be controlled by processes acting on the circulation mode at the mouth of the estuary and estuarine pumping of the krill layer towards the head of the Laurentian Channel. The simulated krill biomass imported into the estuary changed by a factor of 2 over the 3 simulated years.

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Section: Introductionmentioning

confidence: 99%

Krill aggregation in the St. Lawrence system, and supply of krill to the whale feeding grounds in the estuary from the gulf

Sourisseau¹,

Simard²,

Saucier³

2006

Mar. Ecol. Prog. Ser.

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“…Maintenance of a pure population of M. trossulus adults requires environmental conditions favorable for survival of all its life stages and no invasion of external M. edulis larvae or environmental conditions not suitable for the survival of M. edulis. Assuming a 1 mo larval development (Bayne 1965) and a net current velocity of 5 cm s -1 , which is common along the shores of Québec (Huntsman et al 1954, El-Sabh 1976, a mussel larva can drift for ca. 130 km before reaching competency to settle.…”

Section: Introductionmentioning

confidence: 99%

Ontogenetic changes in hyposaline tolerance in the mussels Mytilus edulis and M. trossulus: implications for distribution

Qiu¹,

Tremblay²,

Bourget³

2002

Mar. Ecol. Prog. Ser.

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The effect of salinity (5 to 25 ppt) on Mytilus edulis and M. trossulus that co-exist in Atlantic Canada was examined in 2 laboratory experiments. The first experiment tested the effect of salinity on survival and duration of development from fertilization to settlement in the 2 species. Hyposalinity reduced survivorship and percent metamorphosis, and lengthened duration of development. At 5 and 10 ppt, all early stages of both species died. At 25 ppt, > 90% of individuals of both species survived through the oocyte to swimming embryo and swimming embryo to D-veliger stages, but only ca. 40% survived through the D-veliger to eyed-veliger stage, and 30 to 42% of eyed-veligers successfully metamorphosed. At 15 ppt, the 2 species significantly differed in survival rate, duration of development, and metamorphosis. M. edulis did not develop through any of the 3 stages from oocyte to eyed-veliger. No M. edulis eyed-veligers metamorphosed. In contrast, in M. trossulus, 26% of oocytes and 15% of swimming embryos developed into swimming embryos and D-veligers, respectively, and 13% of eyedveligers metamorphosed into plantigrades. At 20 ppt, some M. edulis developed through each of the 4 stages, but the development time was longer and there was a lower percentage than for the corresponding stage of M. trossulus. The second experiment examined the effect of salinity on survival of juveniles and adults. The 2 species responded to hyposaline stress similarly. Survival ranged from 0 at 5 ppt to 100% at 20 to 25 ppt. At 10 ppt, reproductive status affected mortality, with < 5% mortality in juveniles and post-spawning individuals, but 60 to 67% mortality in reproductive mussels. A similar situation occurred at 15 ppt except there was lower mortality for reproductive individuals. Thus, we found that only in the early ontogenetic stages was M. edulis less tolerant to low salinity stress than M. trossulus. Such difference suggests that selective mortality against M. edulis in early ontogenetic stages rather than post-settlement stage may be responsible for the persistence of a few pure M. trossulus populations along the Gaspé Peninsula. We also found that the ability to tolerate hyposalinity was weakened during the reproductive period, which indicates that salinity may also act as a selective factor in determining the abundance and size structure of wild mussel populations.

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“…The Nova Scotia Current is a coastal current flowing southwestward over the inner Scotian Shelf (Petrie, 1987). This Current originates from the northwestern GSL, where a large-scale estuarine plume and an intense coastal jet known as the Gaspé Current are developed due to a large amount of freshwater discharge from the St. Lawrence River (El-Sabh, 1976;Tang, 1080;Sheng, 2001). The Gaspé Current spreads over the southwestern GSL and exits through western Cabot Strait.…”

Section: Sub-surface Currentsmentioning

confidence: 99%

Circulation, dispersion and hydrodynamic connectivity over the Scotian Shelf and adjacent waters

Sui

Jiang

Ohashi

et al. 2017

som

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Circulation, dispersion and hydrodynamic connectivity over the Scotian Shelf and adjacent waters. © 2017 Yi Sui, et al. This is an Open Access article distributed under the terms of the Creative Commons Attribution-NonCommercial 4.0 International License (http://creativecommons.org/licenses/by-nc/4.0/), permitting all non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. Abstract: A nested-grid ocean circulation modelling system is used in this study to examine the circulation of surface waters over the Scotian Shelf and its adjacent coastal water bodies. The modelling system consists of a coarse-resolution (1/12°) barotropic storm surge (outer) model covering the northwest Atlantic Ocean, and a fine-resolution (1/16°) baroclinic (inner) model covering the Gulf of St. Lawrence, Scotian Shelf, and Gulf of Maine.The three-dimensional model currents are used to track trajectories of particles using a Lagrangian particle-tracking model. The simulated particle movements and distributions are used to examine the dispersion, retention, and hydrodynamic connectivity of surface waters over the study region. The near-surface dispersion is relatively high over western Cabot Strait, the inner Scotian Shelf, and the shelf break of the Scotian Shelf. The dispersion is relatively low in Northumberland Strait. A process study is conducted to examine the physical processes affecting the surface dispersion, including tidal forcing and local wind forcing. The model results show that the tidal currents significantly influence the dispersion of surface waters in the Bay of Fundy. Keywords: circulation model; particle tracking; retention; dispersion; process study

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Surface Circulation Pattern in the Gulf of St. Lawrence

Cited by 79 publications

References 0 publications

Krill aggregation in the St. Lawrence system, and supply of krill to the whale feeding grounds in the estuary from the gulf

Krill aggregation in the St. Lawrence system, and supply of krill to the whale feeding grounds in the estuary from the gulf

Ontogenetic changes in hyposaline tolerance in the mussels Mytilus edulis and M. trossulus: implications for distribution

Circulation, dispersion and hydrodynamic connectivity over the Scotian Shelf and adjacent waters

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