592 research outputs found
Study of Space Cabin Atmospheres Status Report, 1 Jan. - 30 Jun. 1966
Performance characteristics of aerosol generator, and distribution sampling errors of electrostatic precipitator sampling device for space cabin atmospher
Study of space cabin atmospheres Status report, Jul. 1 - Dec. 31, 1967
Calibration of hot-wire detector for particle concentration and size distribution in closed spacecraft cabin atmosphere
Study of space cabin atmospheres Semiannual progress report, 1 Jan. - 30 Jun. 1968
Aerosol measurements in closed cabin environment optimizing geometry of aerosol particle analyzer, and calibrating hot-wire droplet senso
First Records of Sockeye (Oncorhynchus nerka) and Pink Salmon (O. gorbuscha) from Banks Island and Other Records of Pacific Salmon in Northwest Territories, Canada
Eight sexually mature sockeye (Oncorhynchus nerka) and one sexually mature pink salmon (O. gorbuscha) were captured in the subsistence fishery in the Sachs River estuary at Sachs Harbour, Banks Island, Northwest Territories (NT) in August 1993. We also report a first record for coho salmon (O. kisutch) in Great Bear Lake, NT. These capture locations are well outside the known distributions for the species. A pink salmon captured in the West Channel, Mackenzie River near Aklavik, NT, and a chum salmon (O. keta) from Cache Creek [Little Fish Creek], NT, also represent new capture locations within the distribution of the species.En août 1993, on a capturé huit saumons sockeye (Oncorhynchus nerka) adultes et un saumon rose (O. gorbuscha) adulte dans la pêcherie de subsistance située dans l'estuaire de la rivière Sachs, à Sachs Harbour, dans l'île Banks (Territoires du Nord-Ouest). On signale également une première observation du saumon coho (O. kisutch) dans le Grand lac de l'Ours (T.N-O.) Ces lieux de capture sont nettement à l'extérieur des aires de distribution connues pour ces espèces. Un saumon rose capturé dans le Chenal occidental du Mackenzie près d'Aklavik (T.N.-O.), et un saumon kéta (O. keta) provenant de Cache Creek [Little Fish Creek] (T.N.-O.) signalent aussi de nouveaux sites de capture à l'intérieur de l'aire de distribution de ces espèces
Identifying designatable units for intraspecific conservation prioritization : a hierarchical approach applied to the lake whitefish species complex (Coregonus spp.)
The concept of the designatable unit (DU) affords a practical approach to identifying
diversity below the species level for conservation prioritization. However,
its suitability for defining conservation units in ecologically diverse, geographically
widespread and taxonomically challenging species complexes has not been
broadly evaluated. The lake whitefish species complex (Coregonus spp.) is geographically
widespread in the Northern Hemisphere, and it contains a great deal
of variability in ecology and evolutionary legacy within and among populations,
as well as a great deal of taxonomic ambiguity. Here, we employ a set of hierarchical
criteria to identify DUs within the Canadian distribution of the lake white-
fish species complex. We identified 36 DUs based on (i) reproductive isolation,
(ii) phylogeographic groupings, (iii) local adaptation and (iv) biogeographic
regions. The identification of DUs is required for clear discussion regarding the
conservation prioritization of lake whitefish populations. We suggest conservation
priorities among lake whitefish DUs based on biological consequences of
extinction, risk of extinction and distinctiveness. Our results exemplify the need
for extensive genetic and biogeographic analyses for any species with broad geographic
distributions and the need for detailed evaluation of evolutionary history
and adaptive ecological divergence when defining intraspecific conservation
units
Evidence for Non-Anadromous Behaviour of Arctic Charr (Salvelinus alpinus) from Lake Hazen, Ellesmere Island, Northwest Territories, Canada, Based on Scanning Proton Microprobe Analysis of Otolith Strontium Distribution
Scanning proton microprobe analysis was used to determine the distribution of strontium (Sr) in otoliths from arctic charr (Salvelinus alpinus) of known non-anadromous, known anadromous, and unknown life histories. Strontium concentration patterns in otoliths of known non-anadromous charr were low and relatively flat (with little variation) from the core area to the outermost edge of the otolith, while patterns for known anadromous charr were characterized by a similar low, flat region for the first several years of life, followed by marked oscillatory increases and decreases in Sr content for the duration of the fish's life. Small and large forms of Lake Hazen charr of unknown life histories exhibited Sr profiles that were similar to those of the known non-anadromous charr, which strongly suggest that Lake Hazen charr are non-anadromous. These results indicate that Lake Hazen is a "closed" system with energy cycling primarily within the system; this conclusion suggests that a conservative approach would be appropriate for the management of the Lake Hazen charr population.À l'aide d'une sonde protonique à balayage, on a procédé à une analyse afin de déterminer la répartition du strontium (Sr) dans des otolithes prélevés sur des ombles chevaliers (Salvelinus alpinus) ayant eu soit un cycle biologique non anadrome connu, soit un cycle anadrome connu ou un cycle inconnu. Les courbes de concentration en strontium dans les otolithes d'ombles reconnus comme non anadromes étaient faibles et relativement uniformes (montrant peu de fluctuations) en allant du centre de l'otolithe vers la périphérie, tandis que les courbes relatives aux ombles reconnus comme anadromes se caractérisaient par une zone de concentrations faibles et uniformes pour plusieurs des premières années de vie, suivie par des oscillations à la hausse et à la baisse très nettes quant au contenu en Sr pour la durée de vie du poisson. De gros et de petits spécimens d'ombles au cycle biologique inconnu, trouvés dans le lac Hazen, affichaient des profils de Sr semblables à ceux des ombles reconnus comme non anadromes, ce qui suggère fortement que l'omble du lac Hazen est non anadrome. Ces résultats révèlent que le lac Hazen est un système où l'énergie circule surtout en circuit «fermé». Cette conclusion suggère qu'il faudrait adopter une approche prudente quant à la gestion de la population d'ombles du lac Hazen
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