Résultats de la recherche
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A multi-frequency method for improved accuracy and precision of in situ target strength measurements
Abstract: The effectiveness of a split-beam echosounder system to delineate single scatterers and ... synchronized signals from two or more adjacent split-beam transducers of different frequencies. The accuracy of ... from one of the split-beam transducers, additional corresponding TS measurements can be collected with ... juxtaposed single-beam transducers. Both methods were utilized to extract in-situ TS measurements of ...
Meeting Document : WG-EMM-97/24 : Auteur(s): Hewitt, R.P., Soule, M.A., Demer, D.A.
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Pursuit of polynyas in the Antarctic peninsula area
influence biological activity. We pursued daily transition of coastal polynyas in the Antarctic Peninsula ... area from 1978 through 1995 using images of sea ice concentrations by the satellite microwave ... observations. A typical polynya existed off the tip of the Peninsula in 1987 and 1991. In the such years, sea ... ice cover developed extensively. Inversely, the years of the narrow sea ice cover were 1988, 1989,1990 ...
Meeting Document : WG-EMM-97/69 : Auteur(s): Kimura, N., Shibazaki, K., Matsumura, S., Naganobu, M., Okada, Y.
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Dynamics of Antarctic penguin populations in relation to inter-annual variability in sea-ice distribution
Abstract: To investigate the role of sea ice cover on penguin populations we used principal ... component analysis to compare population variables of Adélie (Pygoscelis adeliae) and chinstrap (Pygoscelis ... population size remained stable, whereas that of chinstrap penguins decreased slightly. For neither species ... apparent inverse density-dependent relationship between the number of Adélie breeding pairs and the number ...
Meeting Document : WG-EMM-96/10 : Auteur(s): Murphy, E.J., Croxall, J.P., Trathan, P.N.
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Dynamic model of krill Euphausia superba swarm
, using the 38 and 120 kHz BioSonics dual-beam hydroacoustic system, numerous swarms of krill Euphausia ... superba Dana were registered. Analysis of their physical parameters was carried out. It is known that ... . Using physical parameters of the krills' swarm (density, length), the above assumption was verified ... . It was found that the vertical density pattern of krills' swarm, with a mean density of up to ...
Meeting Document : WG-EMM-95/68 : Auteur(s): Kalinowski, J., Azzali, M.
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Estimates of primary production by ice algae and phytoplankton in the coastal ice-covered area near Syowa Station, Antarctica
Abstract: Annual primary production of ice algae and phytoplankton under fast ice near Syowa ... February 1983 to January 1984 was calculated with a mathematical model based on measured parameters of ... solar radiation, day length, attenuation coefficients of snow, ice and water, chlorophyll a standing ... -2 h-1 in June to 13.3 E m-2 h-1 in December. Relative light intensity estimated at the bottom of sea ...
Meeting Document : WG-KRILL-93/28 : Auteur(s): H. Satoh, K. Watanabe and T. Hoshiai (Japan)
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Orientation of Antarctic krill in an aquarium
slightly less than that when animals were hovering, 49.7° (SD=7.5°, N=50). Such an acute angle of elevation ... . Although mature females with marked swelling of the cephalothorax were not included in the experiment, the ... center of mass was found to be situated more to the anterior than in males and immature females. The ... hovering orientation, which is close to average body orientation, of mature males and mature females was ...
Meeting Document : WG-KRILL-93/24 : Auteur(s): Y. Endo (Japan)
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Remarks on natural mortality of Dissostichus eleginoides in Subarea 48.3
Abstract: With samples originated in the Chilean longline fishery of Dissostichus eleginoides of ... the considered cases with the different growing parameters, with the exception of the case of fishing ... sites. By other hand, when comparing the different mean values of M for the different variables, it was ... hooks N° 22. The general mean value of M calculated for the 44 analyzed situations was 0.14 ± 0.03 ...
Meeting Document : WG-FSA-92/21 Rev. 1 : Auteur(s): C.A. Moreno and P.S. Rubilar (Chile)
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Semi-empirical acoustic estimates of krill biomass derived from simulated commercial fishery data based on single-frequency acoustics
fishing seasons. From these data we develop semi-empirical indices of acoustic biomass in a Generalized ... Linear Modeling framework. We correlate these estimates of biomass with acoustic estimates derived from ... Elephant Island and West Shelf Areas of the US AMLR survey grid. Cross-validation of acoustic estimates ... frequency of animals is skewed towards larger animals. We show that it is possible to develop semi-empirical ...
Meeting Document : SG-ASAM-12/04 : Auteur(s): A.M. Cossio, G.W. Watters, C.S. Reiss, J. Hinke and D. Kinzey (USA)
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Preliminary observation about the possibility of Antarctic krill escapement from a trawl net
underwater video camera attached on the trawl net of Japanese commercial trawler Fukuei-maru (4,350.62 GT) in ... 2011. To avoid the influence of camera lighting on krill behavior, the observation was conducted during ... daytime. Few krill appeared to escape from posterior part of trawl net. When the trawl net caught dense ... krill swarms, krill escaped from anterior part of trawl net. Krill were observed to swim actively after ...
Meeting Document : WG-EMM-12/66 : Auteur(s): K. Fujita and S. Hasegawa (Japan)
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Abundance, distribution, energy density and trophic position of euphausiids during winter 2012: preliminary results from the first US AMLR Winter Survey
sampling program to better understand winter conditions affecting the productivity and survival of ... collection and analysis of water samples from fixed depths. Net tows for euphausiids and other pelagic ... zooplankton taxa are also collected. Here we present preliminary results of a first 8 day shakedown cruise ... reporting the distribution, size and properties of krill and other euphausiids and present some data on ...
Meeting Document : WG-EMM-13/40 : Auteur(s): C. Reiss and C. Jones (USA)