Résultats de la recherche

1. A review of the diet and at-sea distribution of penguins breeding within the CAMLR Convention Area (submitted to the 2008 Joint CCAMLR-IWC Workshop)

   in an ecologically sensitive manner demands that catches do not depress stocks within the foraging ... comparative information for their own findings and by highlighting significant gaps in existing knowledge and ... . These models require information on the number of predators in a population, their nutritional demands ... published information on the diet and at-sea distribution of the six penguin species that breed in the CAMLR ... N15 gives an indication of the trophic level at which an animal feeds, while δC13 indi- cates primary ... coordinated universal time (UTC) of midday. The approach yields two fixes per 24-hour period, with an ... the two birds that reached a polynya with the PTTs still transmitting travelled for 156 and 269 km ... December 2000 to February 2001. All Auster birds and two of the Taylor birds moved an average of 478 km ...

   Science Journal Paper : CCAMLR Science, Volume 19 (CCAMLR Science, Volume 19) : 75–114 : Auteur(s): Ratcliffe, N. and P. Trathan

2. Krill biomass in Area 48 and Area 58: recalculations of FIBEX data

   Green et al. (1990). The new estimates were on average 4.76 times larger than the old estimates for ... estimates of mean density and biomass for the Indian Ocean sector and the West Atlantic sector as well as ... for FAO Statistical Area 41, and CCAMLR Subareas 48.1, 48.2, 48.3, 48.6 and Division 58.4.2. Density ... workshop. Estimates for the different areas were also calculated using the target strength relationships of ... laill for an interval (set either on the basis of time or on distance steamed) of ship's track was ... that all data were available in equivalent units prior to analysis, MVBS values for these two cruises ... densities reported in Anon. (1986) were derived using a TS value of -68.10 dB for a mean animal length of ... - equation 3) to provide an estimate for transect density (Pk). The mean density by stratum (PA) weighted by ...

   Science Journal Paper : Selected Scientific Papers, SC-CAMLR-SSP/9 (Selected Scientific Papers, SC-CAMLR-SSP/9) : 157–181 : Auteur(s): Trathan, P.N., D.J. Agnew, D.G.M. Miller, J.L. Watkins, I. Everson, M.R. Thorley, E. Murphy, A.W.A. Murray and C. Goss

3. A hybrid approach to acoustic classification and length estimation of krill

   / Description:  The problem of acoustically identifying and estimating the sizes of two euphausiid species is ... components are the mean ratios of the volume backscattering coefficients, measured at two different ... individually for each component of a vector, using classical Bayesian techniques. Classification probabilities ... frequencies. The decisions on the species and the relative misclassification errors are calculated ... animal measurement. For small school- ing organisms, such as euphausiids, this criterion is seldom met ... error |δ| is high for afj / fi < a1, decreases approaching the middle point between the two bends ... euphausiids are identifi ed for an output ranging between 4/1 fj fi rfΔ and their equivalent radius can be ... estimated confi dently in the interval (amin – amax) where 100|δ| < 20%, for a given dΔ. The mean length ...

   Science Journal Paper : CCAMLR Science, Volume 11 (CCAMLR Science, Volume 11) : 33–58 : Auteur(s): Azzali, M., I. Leonori and G. Lanciani

4. Is current management of the Antarctic krill fishery in the Atlantic sector of the Southern Ocean precautionary?

   conservatively estimated subarea biomass in up to 20% of years due to high variability in krill biomass indices ... about the state of the regional krill stock. In this region, krill fishing is permitted in an area of ... approximately 3.5 million km 2 which is divided into four subareas (labelled Subareas 48.1 to 48.4) for ... 1991, is 0.62 million tonnes year –1, equivalent to ~1% of the regional biomass estimated in 2000. Each ... for 20 years would reduce the krill stock by 2% (SC-CAMLR, 2011). Clearly, any significantly greater ... tonnes year–1, since 2009. There is some evidence for a decline in the abundance of krill in the 1980s ... exploitation rate (the percentage of an initial biomass that can be caught each year) of 9.1%. The inputs to ... stated as a limit for the krill fishery in CM 32/X in 1991). Each of these limits defines an amount of ...

   Science Journal Paper : CCAMLR Science, Volume 23 (CCAMLR Science, Volume 23) : 31–51 : Auteur(s): Hill, S.L., A. Atkinson, C. Darby, S. Fielding, B.A. Krafft, O.R. Godø, G. Skaret, P.N. Trathan and J.L. Watkins

5. Measurements of differences in the target strength of Antarctic krill (Euphausia superba) swarms at 38 kHz and 120 kHz

   differences in the mean back-scattering strength of swarms simultaneously insonified at these two frequencies ... in average target strength at these two frequencies. The results are in good agreement with recent ... experimental work on the target strength of encaged E. superba at 38 and 120 kHz but are in major conflict with ... Receiving Sensitivity (SL + VRS) for both sounders was measured to within an estimated ± 0.5 dB by ... were interchanged, removing any fear that the differences were an artefact of differences in the two ... Figure 4, and for the two Elephant Island samples in Figure 5. Mean lengths in the two area were 48.75 ... for an error of 0.5 dB in the estimation of SL + VRS, and for the same error in the equivalent beam ...

   Science Journal Paper : Selected Scientific Papers, SC-CAMLR-SSP/7 (Selected Scientific Papers, SC-CAMLR-SSP/7) : 75–86 : Auteur(s): Hampton, I.

6. Fatty acid and stable isotope analyses to infer diet of Antarctic toothfish caught in the southern Ross Sea

   in the southern Ross Sea Abstract / Description:  To infer important prey resources for Antarctic ... evidence that a combination of these two techniques can delineate the main prey items of Antarctic ... sample collection and biomarker analyses for more pelagic and benthic biota are needed to better ... isotope ratio has been used extensively to delineate the trophic position of an animal (DeNiro and ... for freeze-dried organic mat- ter sources and animal tissues with a solution of methanol and ... programmed at 180°C for 5 min, raised from 180°C to 230°C at 3°C min–1, and then finally maintained at 230 ... for 20 replicates of urea was approximately 0.1‰ and 0.3‰ for δ13C and δ15N respectively. δ15N was ...

   Science Journal Paper : CCAMLR Science, Volume 20 (CCAMLR Science, Volume 20) : 21–36 : Auteur(s): Jo, H.-S., I. Yeon, C. Lim, S.M. Hanchet, D.-W. Lee and C.-K. Kang

7. Length-at-age in juvenile Patagonian toothfish (Dissostichus eleginoides)

   density observed. Additionally, ages were predicted for each fish based on length, and compared with ages ... . No difference was found between predicted and estimated ages. We conclude that the two dominant modes ... observed in the length density represent different age cohorts separated by one year. File:  01ashford.pdf ... estimated to be from fish 1+ or 2+ years old, with mean total lengths of 32.5 cm and 41.3 cm respectively ... qij is the proportion of fi sh of age i within an age subsample for a length j. RESULTS Of the ... to the length-frequency peaks shown in Figure 2, indicating that the two large peaks represent year ... + 14+ 20 4 25 2 30 12 1 35 102 7 40 6 33 45 1 65 3 50 5 3 55 7 1 60 2 9 3 65 2 5 1 70 2 1 1 70+ 1 1 ... the region will be needed to clarify this matter. A product of this study is an age–length key for ...

   Science Journal Paper : CCAMLR Science, Volume 9 (CCAMLR Science, Volume 9) : 1–10 : Auteur(s): Ashford, J., C. Jones, S. Bobko and I. Everson

8. Long-term monitoring of krill recruitment and abundance indices in the Elephant Island area (Antarctic Peninsula)

   for the Elephant Island area with regard to the representativeness of the study area (60°-62 o 30´S ... and 53 o-57 o 30´W) for proportional recruit and density indices. Proportional recruitment indices ... one- and two-year-old krill (R 1 and R 2 respectively). Statistically significant fluctuations in ... interannual variability of krill recruitment is confirmed by the present analysis. Results are compared for ... analysis. Results are compared for one- and two-year-old ]an eddy system for another 30 days before ... density may vary by nearly two orders of magnitude and that the effects can persist for several years ... sampling and/or data handling and if calculation of R, (proportion of recruits for 2-year-old krill) may ...

   Science Journal Paper : CCAMLR Science, Volume 4 (CCAMLR Science, Volume 4) : 19–35 : Auteur(s): Siegel, V., W. de la Mare and V. Loeb

9. Trends in relative abundance of fjord Notothenia rossii, Gobionotothen gibberifrons and Notothenia coriiceps at Potter Cove, South Shetland Islands, after commercial fishing in the area

   reported for the period 1983-1990. A trend of increasing N. rossii catches was observed, but the levels of ... inshore sub-populations of N. rossii and G. gibberifrons over the last 16 years was most probably caused ... with historical information on offshore commercial fishing and with the results of scientific surveys ... abundance were analysed using an ANOVA design, grouping the hauls on a sp1it;year basis. The split-year is ... performed on total and relative catches taken at PC are shown in Table 1. Split-year (1 May to 30 April ... . coriiceps. We have used N . coriiceps as a reference species to obtain an abundance index for N. rossii ... defined as the period from 1 May to 30 April next year. Variance was normalised using the trans ...

   Science Journal Paper : CCAMLR Science, Volume 7 (CCAMLR Science, Volume 7) : 43–52 : Auteur(s): Barrera-Oro, E.R., E.R. Marschoff and R.J. Casaux

10. Acoustic data analysis and models of krill spatial distribution

    descriptors of krill spatial aggregation: power spectra for krill biomass fluctuations in space, semivariogram ... wavenumber spectrum resembles a white noise at scales of 2-20 km, although at scales smaller than 1 km the ... over most distances between points except for the distances smaller than 1 km. The computed frequency ... distribution of krill biomass is bimodal and appears to be the mixture of two log normal distributions. These ... and plays an important role in supporting animal populations such as whales, seals and penguins as ... swarms have a diameter smaller than 200 m and that the observed biomass is an average for a 200 m trace ... (cycles/km) Power spectra for krill at the 2-20 km scale observed in this analysis (line) and by Weber ... patch" model of Mangel (1987). 25 20 1.5 1.0 ( 0.5 0.0 0 2 4 6 8 10 12 14 O6T AN:::£ (\ern ...

    Science Journal Paper : Selected Scientific Papers, SC-CAMLR-SSP/5 – Part I (Selected Scientific Papers, SC-CAMLR-SSP/5 – Part I) : 311–329 : Auteur(s): Morin, A., A. Okubo and K. Kawasaki

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