scholarly journals Backscatter strength and shaded seafloor relief, Lunenburg Bay, Scotian Shelf, offshore Nova Scotia

2017 ◽  
Author(s):  
E L King ◽  
D Beaver
Keyword(s):  
Nova Scotia ◽  
Scotian Shelf ◽  
Lunenburg Bay

Behaviour and Vocalizations of Two Single Sperm Whales, Physeter macrocephalus, Off Nova Scotia

1988 ◽  
Vol 45 (10) ◽  
pp. 1736-1743 ◽  
Author(s):  
Julia Mullins ◽  
Hal Whitehead ◽  
Linda S. Weilgart
Keyword(s):  
Nova Scotia ◽  
Sound Production ◽  
Ocean Floor ◽  
Physeter Macrocephalus ◽  
Sperm Whales ◽  
Scotian Shelf ◽  
Male Sperm

During June 1986, two male sperm whales, Physeter macrocephalus, on the Scotian Shelf were tracked by listening for their clicks with a directional hydrophone for periods of 12.5 and 7 h, respectively. Each whale travelled along the edge of the shelf at about 2 kn (3.6 km/h), and one whale, on two occasions at least, dived to the ocean floor. After about 30 min underwater, the whales spent approximately 9 min at the surface breathing. When the whales were visible at the surface, they were silent, except on one occasion when "slow clicking" (mean interclick interval of 4.6 s) was heard from Whale 2. While underwater, most of the sound production consisted of "usual clicks" (mean interclick interval 0.96 and 0.69 s for the two whales) interrupted by frequent short silences (mean durations 21.06 and 27.82 s) and occasional "creaks" (with interclick intervals less than 0.2 s) and "slow clicks." No "codas" (stereotyped patterns of clicks) were heard from these two single whales. These results are consistent with the hypotheses that "usual clicks" and "creaks" are used for echolocation and "codas" for communication.

Comparison of the S/N ratios of low-frequency hydrophones and geophones as a function of ocean depth

1981 ◽  
Vol 71 (5) ◽  
pp. 1649-1659
Author(s):  
Thomas M. Brocher ◽  
Brian T. Iwatake ◽  
Joseph F. Gettrust ◽  
George H. Sutton ◽  
L. Neil Frazer
Keyword(s):  
Nova Scotia ◽  
Continental Margin ◽  
Low Frequency ◽  
Weather Conditions ◽  
Ocean Bottom ◽  
Ocean Bottom Seismometer ◽  
Scotian Shelf ◽  
Ocean Bottom Seismometers ◽  
Particle Velocities ◽  
Refraction Data

abstract The pressures and particle velocities of sediment-borne signals were recorded over a 9-day period by an array of telemetered ocean-bottom seismometers positioned on the continental margin off Nova Scotia. The telemetered ocean-bottom seismometer packages, which appear to have been very well coupled to the sediments, contained three orthogonal geophones and a hydrophone. The bandwidth of all sensors was 1 to 30 Hz. Analysis of the refraction data shows that the vertical geophones have the best S/N ratio for the sediment-borne signals at all recording depths (67, 140, and 1301 m) and nearly all ranges. The S/N ratio increases with increasing sensor depth for equivalent weather conditions. Stoneley and Love waves detected on the Scotian shelf (67-m depth) are efficient modes for the propagation of noise.

Life cycles of four species of Pseudocalanus in Nova Scotia

1989 ◽  
Vol 67 (3) ◽  
pp. 552-558 ◽  
Author(s):  
I. A. McLaren ◽  
Estelle Laberge ◽  
C. J. Corkett ◽  
J.-M. Sévigny
Keyword(s):  
Life Cycle ◽  
Nova Scotia ◽  
First Generation ◽  
Early Summer ◽  
Life Cycles ◽  
The Arctic ◽  
Late Winter ◽  
Early Winter ◽  
Temperature Dependent ◽  
Scotian Shelf

The primarily arctic Pseudocalanus acuspes, relict in Bedford Basin, Nova Scotia, produces a first generation (G1) in late winter; most G1 individuals mature in late spring. The G1 then produces a G2, most of which "rest" in copepodite stages III and IV until early winter. These stages store large amounts of lipid in early summer, which slowly diminish subsequently. A small number of G2 individuals continue to develop at temperature-dependent rates, maturing in early autumn and producing G3 adults in November. Copepodites developing in winter and spring store less lipid. The primarily arctic Pseudocalanus minutus, rare in Bedford Basin and on the Scotia Shelf, is strictly annual, developing to a lipid-filled copepodite stage V after spawning in late winter. The arctic–temperate Pseudocalanus newmani is abundant on the Scotian Shelf, but may not be self-sustaining when advected into Bedford Basin. It stores little lipid and appears to have at least three mature generations at temperature-dependent intervals over Browns Bank between May and November. It may rest in winter, or its life-cycle synchrony by spring could result from food-limited development during winter. The temperate Pseudocalanus moultoni appears to have a life cycle similar to that of P. newmani, but was less common during summer on Browns Bank. These life cycles are appropriately adapted to the geographical ranges of the species, and show some parallels with species of Calanus.

Assessing the performance of a multi-nested ocean circulation model using satellite remote sensing and in situ observations

2016 ◽  
Vol 1 (1) ◽  
Author(s):  
Shiliang Shan ◽  
Jinyu Sheng ◽  
Kyoko Ohashi ◽  
Mathieu Dever
Keyword(s):  
Remote Sensing ◽  
Nova Scotia ◽  
Ocean Circulation ◽  
Satellite Remote Sensing ◽  
Coastal Upwelling ◽  
Circulation Model ◽  
Tidal Mixing ◽  
Scotian Shelf ◽  
Ocean Circulation Model

This study presents a multi-nested ocean circulation model developed recently for the central Scotian Shelf. The model consists of four submodels downscaling from the eastern Canadian Shelf to the central Scotian Shelf. The model is driven by tides, river discharges, and atmospheric forcing. The model results are validated against observations, including satellite remote sensing data from GHRSST and Aquarius and in situ measurements taken by tide gauges, a marine buoy, ADCPs and CTDs. The ocean circulation model is able to capture variations of sea level, hydrography and the Nova Scotia Current on timescales of days to seasons over the central Scotian Shelf. Model results are used in a process study to examine the effect of tidal mixing and wind-driven coastal upwelling in the formation of cold surface waters along the coast of Nova Scotia.

scholarly journals The marine geology of the inner Scotian Shelf off the south shore, Nova Scotia

1986 ◽  
Author(s):  
D J W Piper ◽  
P J Mudie ◽  
J R J Letson ◽  
N E Barnes ◽  
R J Iuliucci
Keyword(s):  
Nova Scotia ◽  
Marine Geology ◽  
The South ◽  
Scotian Shelf ◽  
South Shore

scholarly journals BIOLOGICAL AND ENVIRONMENTAL REQUISITES FOR A SUCCESSFUL TRAP FISHERY OF THE NORTHERN SHRIMP Pandalus borealis

2007 ◽  
Vol 44 (1) ◽  
Author(s):  
P. Koeller ◽  
M. Covey ◽  
M. King
Keyword(s):  
Nova Scotia ◽  
Seasonal Pattern ◽  
Late Summer ◽  
Maximum Size ◽  
Scotian Shelf ◽  
Pandalus Borealis ◽  
Small Vessels ◽  
Trap Fishery ◽  
Aire De Répartition ◽  
Catch Rates

A permanent trap fishery for northern pink shrimp (Pandalus borealis) was established in Chedabucto Bay, Nova Scotia in 1996 after several years of experimental trapping by one fisherman. Despite extensive experimental trapping projects elsewhere in Nova Scotia, only in one other area, Mahone Bay, has a long-term fishery been successfully established. The successful trapping of shrimp from small vessels off the coast of Nova Scotia appears to be dependant on a number of requisite conditions, including the presence of soft mud habitat and low temperatures in large, relatively deep coastal embayments. Catch rates for the established inshore trap fisheries increase in late summer-fall and decrease in spring, suggesting that an inshore migration occurs in the fall from adjacent “feeder” populations. In addition to the seasonal pattern of trapcatches, cyclical changes at a finer temporal scale were observed that appear to be related to tidal cycles, with higher catch rates associated with greater tidal ranges. Coupled with known diurnal vertical migratory behaviour, this pattern could arise as more water, and the shrimp within it, pass horizontally over the trap and come into contact with its bait plume during greater tidal ranges. More complex, selective vertical migration coupled with tidal drift may result in net movement into areas such as Chedabucto Bay. Analysis of length at sex transition and maximum size suggests that shrimp trapped in Chedabucto Bay come from the same population as those caught by trawlers inshore and offshore on the eastern Scotian Shelf. Shrimp trapped in Mahone Bay and St. Margaret’s Bay have significantly different growth characteristics and are probably from a different population. Thus the Mahone Bay and St. Margaret’s Bay population appears to be more locally confined than the widespread shrimp population on the eastern Scotian Shelf, possibly originating from areas within and immediately adjacent to these bays.Une pêche annuelle de la crevette nordique (Pandalus borealis) au casier a étéétablie dans la baie Chedabucto (Nouvelle‑Écosse) en 1996, après plusieurs années de pêche expérimentale au casier par un pêcheur. Malgré les nombreux projets de pêche expérimentale au casier menés ailleurs dans la province, une pêche à long terme a été établie avec succès dans seulement un autre secteur (la baie Mahone). La réussite de la pêche de la crevette au casier par les petits bateaux au large de la côte de la Nouvelle‑Écosse semble dépendre d’un certain nombre de conditions, y compris la présence d’un habitat vaseux mou et de basses températures dans de grandes échancrures relativement profondes de la côte. Les taux de capture pour les pêches côtières au casier établies augmentent à la fin de l’été et à l’automne et baissent au printemps, ce qui suggère que les crevettes migrent de populations sources vers la côte à l’automne. En plus de ce profil saisonnier des prises dans les casiers, deschangements cycliques à une échelle temporelle plus fine ont été observés et ceux‑ci semblent liés au cycle de marée, le taux de capture étant plus élevé lorsque l’amplitude de la marée est grande. Combiné au comportement de migration verticale diurne, ce profil pourrait survenir quand la quantité d’eau (et les crevettes qu’elle contient) qui passe horizontalement au-dessus des casiers est grande et qu’elle entre en contact avec le panache d’attractifs des casiers durant les périodes de grande amplitude de la marée. Une migration verticale sélective plus complexe combinée à une dérive tidale pourrait donner lieu à un mouvement net vers les secteurs comme la baie Chedabucto. L’analyse de la longueur au moment du changement de sexe et de la taille maximale suggère que les crevettes piégées dans la baie Chedabucto appartiennent à la mêmepopulation que celles capturées par les chalutiers en milieux côtiers et extracôtiers dans la partie est du plateau néo‑écossais. Les crevettes piégées dans les baies Mahone et St. Margaret’s ont des caractéristiques de croissance considérablement différentes et font probablement partie d’une autre population. Ainsi, la population des baies Mahone et St. Margaret’s semble avoir une aire de répartition beaucoup plus limitée que la population étendue de crevettes dans la partie est du plateau néo‑écossais, et elle provient peut-être de secteurs à l’intérieur de ces baies ou adjacents à celles-ci.

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