Résultats de la recherche
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USING GENERALIZED DISSIMILARITY MODELLING TO ANALYSE AND PREDICT PATTERNS OF BETA DIVERSITY IN REGIONAL BIODIVERSITY ASSESSMENT
predicting spatial patterns of turnover in community composition (beta diversity) across large regions. The ... approach is an extension of matrix regression, designed specifically to accommodate two types of ... ) the variation in the rate of compositional turnover at different positions along environmental ... gradients. GDM can be further adapted to accommodate special types of biological and environmental data ...
Meeting Document : WS-VME-09/P03 : Auteur(s): Richardson, K., Manion, G., Ferrier, S., Elith, J.
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Community Structure of copepods in epipelagic layers in the Ross Sea and neighboring waters
Abstract: During the 9th research cruise of the R/V Kaiyo-maru, copepod samples were collected ... groups by cluster analysis based on species abundance and composition. Group 1 located in the north of ... the Southern Boundary of the Antarctic Circumpolar Current was characterized by high abundance (157.5 ... -2279.5; mean 610.5 inds. 1000 m-3) and dominance of Rhincalanus gigas (mean 88.4%). Group 2 located off ...
Meeting Document : WG-EMM-08/36 : Auteur(s): Y. Watanabe, S. Sawamoto, T. Ishimaru and M. Naganobu (Japan)
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UPDATE ON ITEMS OF INTEREST TO WG-IMAF
(Convention seabirds) is detailed. This paper includes a tabulation of observed captures by species and ... bycatch estimations by fishery for all seabirds. This paper also contains description of the recent and ... Economic Zone that are relevant to the work of WG-IMAF. These developments include refinement of the ... requirement of fishing practices to reduce seabird bycatch by surface longline vessels and the introduction of ...
Meeting Document : WG-FSA-08/47 : Auteur(s): N. Walker (New Zealand)
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Interannual variation in the diet of the Antarctic prion Pachyptila desolata at South Georgia
Abstract: The diet of the Antarctic Prion Pachyptila desolata was examined using food samples ... was mainly crustaceans, with a small proportion of myctophid fish and trace amounts of cephalopods ... copepods, especially Rhincalanus gigas and Calanoides acutus, in two years of low krill abundance ... . Differences in the prey species taken and observations of foraging behaviour suggest that in years of low ...
Meeting Document : WG-EMM-97/12 : Auteur(s): Croxall, J.P., Edwards, T.M., Reid, K.
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Conditions for the precise measurement of fish target strength in situ
Abstract: Conditions for precise measurement of in situ fish target strength (TS) are empirically ... studied and two indexes are introduced for this purpose. One is the number of fish in the effective ... reverberation volume which contributes echo formation at a certain instant and the other is the percentage of ... the multiple echoes which is derived from a residual of the single echo extraction. With the decrease ...
Meeting Document : WG-Krill-94/35 : Auteur(s): K. Sawada and M. Furusawa (Japan), N.J. Williamson (USA)
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Status of krill target strength
Abstract: Empirical estimates for the target strength of krill are extracted from the literature ... . These are confined to measurements on aggregations of live euphausiids, which should avoid a frequent ... cause of bias in single-animal measurements, namely thresholding. Theoretical estimates for the target ... strength are derived from the deformed-cylinder scattering model assuming specific sets of physical and ...
Meeting Document : WG-KRILL-92/11 : Auteur(s): K.G. Foote (Norway), D. Chu and T.K. Stanton (USA)
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Pup production and distribution of breeding Antarctic fur seals (Arctocephalus gazella) at South Georgia
Abstract: A census of the breeding population of Antarctic fur seals (Arctocephalus gazella) at ... South Georgia was carried out during the 1990/91 breeding season. Using counts of adult females ashore ... at the breeding grounds during the pupping period, together with corrections for the likelihood of a ... long-term study sites probably because of a short term reduction in food availability. Data from these ...
Meeting Document : WG-CEMP-92/39 : Auteur(s): I.L. Boyd (United Kingdom)
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Estimation of krill (Euphausia superba) mortality and production rate in the Antarctic peninsula region
Peninsula from 26 December 1989 to 14 January 1990. Results were compared with data of an identical survey ... exceeded a factor of 35 times, while interannual variability between available surveys reached only a ... factor of 1.6 times. Krill mortality was calculated by linearized catch curve analysis and resulted a ... rate of Z=0.88 (1989/90) and Z=0.96 (1987/88). Production was estimated and resulted a P/B ratio of ...
Meeting Document : WG-KRILL-91/15 : Auteur(s): Delegation of Germany
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On the problem of icefish (Champsocephalus gunnari) vertical migration on the South Georgia shelf
Abstract: The results are presented of studying icefish vertical migration based on the data of R ... /V cruises during the seasons of 1982-83, 1983-84 and 1986-87, when this species was highly abundant ... the maximum catches were available at the middle of the light hours of the day. At twilight the fish ... concentrations migrate into the water column and the catches greatly decrease. The direct observations of icefish ...
Meeting Document : WG-FSA-91/06 : Auteur(s): J.A. Frolkina and V.I. Shlibanov (USSR)
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A Comparison Between Age Determinations of the Antarctic Fish Notothenia gibberifrons Lönnberg Using Scales and Otoliths
Abstract: Scales and otoliths were collected from 304 specimens of the Antarctic fish Notothenia ... gibberifrons. When interpreted separately, only 25% of scale and otolith readings agreed. When a scale and ... otolith from a single simultaneously, 75% of readings agreed. of otolith readings changed between specimen ... were interpreted 60% of scale readings and 30% separate and simultaneous interpretations. Estimates of ...
Meeting Document : WG-FSA-89/13 : Auteur(s): R. Coggan (United Kingdom), K. Skora (Poland), A. Murray and M. White (United Kingdom)