Resultados de la búsqueda
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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 : Autor(es): 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 : Autor(es): 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 : Autor(es): 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 : Autor(es): 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 : Autor(es): R. Coggan (United Kingdom), K. Skora (Poland), A. Murray and M. White (United Kingdom)
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Analysis of observer coverage for Japanese krill fishing vessels
Abstract: Sources of variability of krill mean length and fish bycatch number was investigated to ... explore proper allocation of scientific observers on Japanese krill fishing vessels using the data from ... 1995 to 2008. Based on the multistage sampling theory, we derived the equation of variance in four ... coefficients of variation (CV) caused by the shifts in coverage at different sampling stages. Vessel coverage ...
Meeting Document : WG-SAM-10/17 : Autor(es): T. Okuda, M. Kiyota and H. Okamura (Japan)
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Two decades of variability in krill predators at Bird Island, South Georgia and their potential as ecosystem indicators
Abstract: The breeding performance of seabirds and seals at Bird Island, South Georgia, in the ... Southern Ocean, has been recorded annually for over two decades as part of a large marine ecosystem ... monitoring programme. We examined the mechanistic relationships between, and patterns of inter-annual ... included foraging performance, offspring survival, offspring mass, the contribution of Antarctic krill ...
Meeting Document : WG-EMM-12/16 : Autor(es): S.L. Hill, C.M. Waluda, H.J. Peat and S. Fielding (United Kingdom)
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Potential climate change effects on the habitat of Antarctic krill
summer foraging sites of many of these predators are concentrated between 0° and 90°W. Parts of this ... sector have experienced recent localised sea surface warming of up to 0.2°C per decade, and ... projections suggest that further widespread warming of 0.27° to 1.08°C will occur by the late 21st century. We ... assess the influence of projected warming on Antarctic krill habitat quality. The results divide the ...
Meeting Document : WG-EMM-13/20 : Autor(es): S.L. Hill, T. Phillips and A. Atkinson (United Kingdom)
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A preliminary assessment of mackerel icefish (Champsocephalus gunnari) in Division 58.5.2, based on results from the 2013 random stratified trawl survey
vicinity of Heard Island during April 2013. This paper provides a preliminary assessment of mackerel ... icefish population structure, abundance and yield for the area of Division 58.5.2 to the west of 79° 20’ E ... using standard CCAMLR methods. A large cohort of fish, estimated to be 3+, dominates the population in ... both abundance and biomass. Two scenarios for harvest are presented – a typical two year projection of ...
Meeting Document : WG-FSA-13/23 : Autor(es): D.C. Welsford (Australia)
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An updated spatially explicit population dynamics operating model for Antarctic toothfish in the habitable depths of the Ross Sea region
population was restricted to those cells in which at least 5% of cell area was of a depth deemed suitable as ... that a proportion of the mature fish spawn each year. The model estimation of the maturity ogive is now ... similar to that estimated by histological analysis. This model represents our current best model of the ... spatial distribution and movement of Antarctic toothfish in the Ross Sea region given the movement ...
Meeting Document : WG-SAM-14/31 : Autor(es): S. Mormede, A. Dunn, S. Parker and S. Hanchet (New Zealand)