Breeding success of the black-crowned night heron in the St. Lawrence Estuary

1980 ◽  
Vol 58 (7) ◽  
pp. 1259-1263 ◽  
Author(s):  
Jacqueline Tremblay ◽  
Laurence N. Ellison
Keyword(s):  
Toxic Chemical ◽  
Active Nest ◽  
Lawrence Estuary ◽  
Nycticorax Nycticorax ◽  
Eggshell Thinning ◽  
Chemical Residues ◽  
Night Heron ◽  
Mean Size ◽  
The Mean ◽  
St Lawrence Estuary

Reproductive success of black-crowned night herons (Nycticorax nycticorax) was studied on two islands during 2 years in the St. Lawrence Estuary. The mean size of complete clutches was 4.1 eggs. The mean number of young fledged per active nest varied from 0.5 to 2.1 young according to year and to island. The mean number of young fledged per successful nest varied from 2.1 to 3.0. Toxic chemical residues in eggs were relatively low, and we found no evidence of eggshell thinning. We conclude that reproduction was normal and probably sufficient to maintain a stable population.

The effects of bird predation on an estuarine stickleback (Pisces: Gasterosteidae) community

1985 ◽  
Vol 63 (2) ◽  
pp. 301-307 ◽  
Author(s):  
F. G. Whoriskey ◽  
G. J. Fitzgerald
Keyword(s):  
Fish Community ◽  
Gasterosteus Aculeatus ◽  
Selective Predation ◽  
Bird Predation ◽  
Lawrence Estuary ◽  
Nycticorax Nycticorax ◽  
Larus Delawarensis ◽  
Night Heron ◽  
Marsh Pools ◽  
St Lawrence Estuary

Eight species of birds fed on a community of sticklebacks living in salt marsh pools along the southern shore of the St. Lawrence estuary in May and June when the fish breed. Three birds, the black-crowned night heron (Nycticorax nycticorax), the bronzed grackle (Quiscalus quiscula), and the ring-billed gull (Larus delawarensis) accounted for 80% of the estimated captures. Bird predation removed about 30% of the sticklebacks in the marsh. Significantly more male than female Gasterosteus aculeatus and G. wheatlandi were eaten, indicating selective predation is playing a role in structuring this fish community.

Evidence for differential predation on an estuarine stickleback community

1981 ◽  
Vol 59 (12) ◽  
pp. 2394-2395 ◽  
Author(s):  
Gérard J. FitzGerald ◽  
Jean-Denis Dutil
Keyword(s):  
Gasterosteus Aculeatus ◽  
Pungitius Pungitius ◽  
Lawrence Estuary ◽  
Nycticorax Nycticorax ◽  
Nest Sites ◽  
Differential Predation ◽  
Apeltes Quadracus ◽  
Breeding Grounds ◽  
Night Heron ◽  
St Lawrence Estuary

The diet of the black-crowned night heron (Nycticorax nycticorax) feeding in June and July along the southern shore of the St. Lawrence Estuary was composed primarily of the threespine stickleback Gasterosteus aculeatus. Three other sticklebacks, G. wheatlandi, Pungitius pungitius, and Apeltes quadracus occur in areas where the birds feed but were not eaten. It is suggested that differential predation on G. aculeatus may diminish interspecific competition for nest sites where the four stickleback species co-occur on the breeding grounds.

Autumnal patterns of nocturnal passerine migration in the St. Lawrence estuary region, Quebec, Canada: a weather radar study

2011 ◽  
Vol 89 (1) ◽  
pp. 31-46 ◽  
Author(s):  
François Gagnon ◽  
Jacques Ibarzabal ◽  
Jean-Pierre L. Savard ◽  
Marc Bélisle ◽  
Pierre Vaillancourt
Keyword(s):  
The United States ◽  
North Coast ◽  
Lawrence Estuary ◽  
Migratory Activity ◽  
Late Night ◽  
The North ◽  
Flight Direction ◽  
The Mean ◽  
St Lawrence Estuary ◽  
Passerine Migration

We documented the pattern of nocturnal passerine migration on each side of the St. Lawrence estuary (Côte-Nord north and Gaspésie south), using the Doppler Canadian weather surveillance radar of Val d’Irène (XAM). We examined whether autumnal migrants flew across the St. Lawrence, resulting in a uniform broad-front migration, or avoided crossing it, resulting in a bird concentration along the north coast. We found that a proportion of migrants crossed the estuary but that most followed the north coast. Ranges at which birds were detected were, on average, greater on Côte-Nord, thereby rejecting the uniform broad-front migration hypothesis, inasmuch as reflectivity measurements suggested that bird concentrated along Côte-Nord. The mean flight direction on Côte-Nord was southwest but shifted westward as the night progressed, avoiding crossing the estuary by late night. In Gaspésie, the mean flight direction over land was south and no directional shift was observed throughout the night. Flight altitude reach up to 1000 m above sea level (a.s.l.), but migratory activity was highest in the first 500 m a.s.l. It appears that the St. Lawrence estuary acts as a leading line and a barrier for nocturnal passerine migrants, and likely shapes migration farther south in Canada and in the United States.

Habitat use and movements of postfledging American black ducks (Anas rubripes) in the St. Lawrence estuary, Quebec

1994 ◽  
Vol 72 (12) ◽  
pp. 2100-2104 ◽  
Author(s):  
David A. Clugston ◽  
Jerry R. Longcore ◽  
Daniel G. McAuley ◽  
Pierre Dupuis
Keyword(s):  
Habitat Use ◽  
Home Range Size ◽  
Hunting Season ◽  
Lawrence Estuary ◽  
Anas Rubripes ◽  
North Shore ◽  
The North ◽  
American Black ◽  
The Mean ◽  
St Lawrence Estuary

We used radiotelemetry to determine habitat use and movements of 38 female juvenile American black ducks (Anas rubripes) on the north shore of the St. Lawrence estuary, Quebec, from 28 August to 15 November 1991. Ducks separated into three groups based on habitat use: inland, estuarine, and those using a mixture of habitats. Ducks using mixed habitats used the greatest variety of habitat types, flew the greatest distances and most often between night roosts and day foraging areas, and were unlikely to be shot. The mean distance flown between night-use and day-use areas for all ducks increased nearly 50% after the hunting season began (overall mean = 6104 m, range 1500 – 26 384 m). Mean home range size was 27.6 ± 6.5 (SE) km2. Ducks exhibited stronger fidelity to wetlands used at night than to those used during the day. Ducks that were shot spent a high percentage of their time on the estuary (90.1 ± 7.4%) and exhibited high fidelity to a day-use area before the hunting season (73 ± 7.3%).

Batch Precipitation of Lead Iodide

1994 ◽  
Vol 59 (6) ◽  
pp. 1301-1304
Author(s):  
Jaroslav Nývlt ◽  
Stanislav Žáček
Keyword(s):  
Aqueous Solution ◽  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Crystal Size ◽  
Lead Nitrate ◽  
Lead Iodide ◽  
Constant Rate ◽  
Mean Size ◽  
The Mean

Lead iodide was precipitated by a procedure in which an aqueous solution of potassium iodide at a concentration of 0.03, 0.10 or 0.20 mol l-1 was stirred while an aqueous solution of lead nitrate at one-half concentration was added at a constant rate. The mean size of the PbI2 crystals was determined by evaluating the particle size distribution, which was measured sedimentometrically. The dependence of the mean crystal size on the duration of the experiment exhibited a minimum for any of the concentrations applied. The reason for this is discussed.

scholarly journals Benthic fluxes of dissolved organic nitrogen in the lower St. Lawrence estuary and implications for selective organic matter degradation

2013 ◽  
Vol 10 (11) ◽  
pp. 7609-7622 ◽  
Author(s):  
M. Alkhatib ◽  
P. A. del Giorgio ◽  
Y. Gelinas ◽  
M. F. Lehmann
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Nitrogen ◽  
Organic Nitrogen ◽  
Bottom Water ◽  
Estuarine Sediments ◽  
Internal Source ◽  
Lawrence Estuary ◽  
Element Partitioning ◽  
Sediment Porewaters ◽  
St Lawrence Estuary

Abstract. The distribution of dissolved organic nitrogen (DON) and carbon (DOC) in sediment porewaters was determined at nine locations along the St. Lawrence estuary and in the gulf of St. Lawrence. In a previous manuscript (Alkhatib et al., 2012a), we have shown that this study area is characterized by gradients in the sedimentary particulate organic matter (POM) reactivity, bottom water oxygen concentrations, and benthic respiration rates. Based on the porewater profiles, we estimated the benthic diffusive fluxes of DON and DOC in the same area. Our results show that DON fluxed out of the sediments at significant rates (110 to 430 μmol m−2 d−1). DON fluxes were positively correlated with sedimentary POM reactivity and varied inversely with sediment oxygen exposure time (OET), suggesting direct links between POM quality, aerobic remineralization and the release of DON to the water column. DON fluxes were on the order of 30 to 64% of the total benthic inorganic fixed N loss due to denitrification, and often exceeded the diffusive nitrate fluxes into the sediments. Hence they represented a large fraction of the total benthic N exchange, a result that is particularly important in light of the fact that DON fluxes are usually not accounted for in estuarine and coastal zone nutrient budgets. In contrast to DON, DOC fluxes out of the sediments did not show any significant spatial variation along the Laurentian Channel (LC) between the estuary and the gulf (2100 ± 100 μmol m−2 d−1). The molar C / N ratio of dissolved organic matter (DOM) in porewater and the overlying bottom water varied significantly along the transect, with lowest C / N in the lower estuary (5–6) and highest C / N (> 10) in the gulf. Large differences between the C / N ratios of porewater DOM and POM are mainly attributed to a combination of selective POM hydrolysis and elemental fractionation during subsequent DOM mineralization, but selective adsorption of DOM to mineral phases could not be excluded as a potential C / N fractionating process. The extent of this C- versus N- element partitioning seems to be linked to POM reactivity and redox conditions in the sediment porewaters. Our results thus highlight the variable effects selective organic matter (OM) preservation can have on bulk sedimentary C / N ratios, decoupling the primary source C / N signatures from those in sedimentary paleoenvironmental archives. Our study further underscores that the role of estuarine sediments as efficient sinks of bioavailable nitrogen is strongly influenced by the release of DON during early diagenetic reactions, and that DON fluxes from continental margin sediments represent an important internal source of N to the ocean.

Pre-exposure to Cu2+ and CuO NPs leads to infection of caged blue mussels, Mytilus edulis L., by pathogenic microalga: Pilot study in the Lower St. Lawrence Estuary (Québec, Canada)

2021 ◽  
Vol 166 ◽  
pp. 112180
Author(s):  
Michael Zuykov ◽  
Galina Kolyuchkina ◽  
Graeme Spiers ◽  
Michel Gosselin ◽  
Philippe Archambault ◽  
...  
Keyword(s):  
Pilot Study ◽  
Mytilus Edulis ◽  
Lawrence Estuary ◽  
Blue Mussels ◽  
Cuo Nps ◽  
St Lawrence Estuary

scholarly journals Effects of topical gel formulation of Ficus carica latex on cutaneous leishmaniasis induced by Leishmania major in BALB/c mice

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Ali Pouryousef ◽  
Erfan Eslami ◽  
Sepehr Shahriarirad ◽  
Sina Zoghi ◽  
Mehdi Emami ◽  
...  
Keyword(s):  
Cutaneous Leishmaniasis ◽  
Murine Model ◽  
Leishmania Major ◽  
Considerable Effect ◽  
Ficus Carica ◽  
Control Group ◽  
Topical Gel ◽  
The Third ◽  
Mean Size ◽  
The Mean

Abstract Objectives The current study aimed to evaluate the effects of Ficus carica latex on the treatment of cutaneous leishmaniasis (CL), induced by Leishmania major. A 5% topical gel with F. carica latex was prepared. BALB/c mice were infected by inoculation of amastigotes form of L. major. Thirty BALB/c mice were divided into five groups, where the first group was treated daily, the second group twice per day, and the third group every other day with the 5% topical gel, for 3 weeks. The sizes of the lesions were measured before and during the course of treatment. Results Although the mean size of lesions in the mice group treated with the 5% F. carica gel, especially in the group receiving daily treatment, was less than the mean size of the lesions in the control group, yet, the differences was not statistically significant (p > 0.05). The findings of the current study demonstrated that the 5% F. carica latex with a 3-week course of treatment had no considerable effect in recovery or control of CL induced by L. major in the murine model. Using higher concentration of F. carica latex and with longer treatment lengths may increase its efficacy in the treatment of CL.

scholarly journals Mudrock Microstructure: A Technique for Distinguishing between Deep-Water Fine-Grained Sediments

Minerals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 653
Author(s):  
Shereef Bankole ◽  
Dorrik Stow ◽  
Zeinab Smillie ◽  
Jim Buckman ◽  
Helen Lever
Keyword(s):  
Grain Size ◽  
Deep Water ◽  
Sedimentary Facies ◽  
X Ray Diffraction ◽  
Weak Current ◽  
Large Area ◽  
Fine Grained ◽  
Mean Size ◽  
The Mean ◽  
Water Facies

Distinguishing among deep-water sedimentary facies has been a difficult task. This is possibly due to the process continuum in deep water, in which sediments occur in complex associations. The lack of definite sedimentological features among the different facies between hemipelagites and contourites presented a great challenge. In this study, we present detailed mudrock characteristics of the three main deep-water facies based on sedimentological characteristics, laser diffraction granulometry, high-resolution, large area scanning electron microscopy (SEM), and the synchrotron X-ray diffraction technique. Our results show that the deep-water microstructure is mainly process controlled, and that the controlling factor on their grain size is much more complex than previously envisaged. Retarding current velocity, as well as the lower carrying capacity of the current, has an impact on the mean size and sorting for the contourite and turbidite facies, whereas hemipelagite grain size is impacted by the natural heterogeneity of the system caused by bioturbation. Based on the microfabric analysis, there is a disparate pattern observed among the sedimentary facies; turbidites are generally bedding parallel due to strong currents resulting in shear flow, contourites are random to semi-random as they are impacted by a weak current, while hemipelagites are random to oblique since they are impacted by bioturbation.

Movement of sturgeons ( Acipenser oxyrinchus oxyrinchus and A. fulvescens ) in the St. Lawrence Estuary: A 35‐year tagging study

2021 ◽  
Author(s):  
Yves Paradis ◽  
Marc Pépino ◽  
Simon Bernatchez ◽  
Denis Fournier ◽  
Léon L’Italien ◽  
...  
Keyword(s):  
Lawrence Estuary ◽  
St Lawrence Estuary ◽  
Acipenser Oxyrinchus
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