Résultats de la recherche

1. A simple approach for calculating the potential yield of krill from biomass survey results

   for the calculations is that the probability that the krill spawning biomass drops below 20% of its ... relative values of the ages at maturity and first-capture. Seasonal effects seem to be of lesser importance ... suggested that a possible approach to the determination of appropriate yields might be to use the formula ... . The reason is that, in practice, such a strategy could only be implemented in the form of fixed ... the likelihood that further surveys will take place, and that their results could also be ... that a+ = 1+ would be an appropriate choice. [Given a value for M, the multiplicative factors ...

   Science Journal Paper : Selected Scientific Papers, SC-CAMLR-SSP/8 (Selected Scientific Papers, SC-CAMLR-SSP/8) : 207–217 : Auteur(s): Butterworth, D.S., A.E. Punt and M. Basson

2. Genetic variations and population structure of krill from the Prydz Bay region of Antarctic waters

   consistent with the hypothesis that all samples were derived from a single breeding population of krill. The ... results of this study agree closely with genetic data from other studies on krill in the Atlantic sector ... of the Southern Ocean, suggesting that krill stocks over at least 6000 kilometres of Antarctic waters ... result consistent with the hypothesis that all samples were derived from a single breeding population ... of krill. The results of this study agree closely with genetic data from other studies on krill in ... the Atlantic sector of the Southern Ocean, suggesting that krill stocks over at least 6000 ...

   Science Journal Paper : Selected Scientific Papers, SC-CAMLR-SSP/3 (Selected Scientific Papers, SC-CAMLR-SSP/3) : 271-273 : Auteur(s): MacDonald, C.M., R. Williams and M. Adams

3. Catch-at-age analysis applied to new fisheries: the case of Dissostichus eleginoides

   develop a comprehensive sampling design which will provide data in line with assessment procedures that ... fish stocks, which seriously affect model assumptions. This paper demonstrates that for the new fishery ... Dissostichus eleginoides off the south of Chile which is being conducted in accordance with CCAMLR regulations ... which will provide data in line with assessment procedures that are quite similar to those commonly ... , managed so as to collect series of data which can be analysed in conjunction with stock dynamics models ... sensitive to the tails of age distributions. This suggests that the target function should be weighted by ... obtained with these methods when they are fitted to catch curves that come from virgin stock. Also, the ...

   Science Journal Paper : Selected Scientific Papers, SC-CAMLR-SSP/9 (Selected Scientific Papers, SC-CAMLR-SSP/9) : 3–9 : Auteur(s): Zuleta, A.V. and C.A. Moreno

4. Revised estimates of seabed areas within the 500 m isobath of the South Orkney Islands (subarea 48.2) and consequences for standing stock biomass estimates of nine species of finfish

   the 50-500 m isobaths than Everson's estimates, though changes in area are specific to the depth ... , estimated biomass and variability will be higher within a sampling stratum for species with higher ... depths, it follows that species with the greatest positive percentage change in biomass estimates are ... given strata j and the area Ajof that strata (de la Mare, 1994). Similarly, variance irB2 of abundance ... of the raw data follows that of Jones et al. (1999). Briefly, raw data of the combined information ...

   Science Journal Paper : CCAMLR Science, Volume 7 (CCAMLR Science, Volume 7) : 197–204 : Auteur(s): C.D. Jones

5. Beyond MSY: a consideration of definitions of management objectives

   recruitment or growth overfishing. Account also needs to be taken of the uncertainties associated with any ... Article II of the CCAMLR Convention. The criteria will depend on whether the main concern is with ... doing this. It may also be noted that because recruitment effects are not dealt with, FO . l may not ... be determined. Sissenwine and Shepherd propose the use of the median line, i.e. that with equal ... be met by taking an amount R-S t' so that the escapement (i.e. recruitment op less catch) will ... maintained at S t' then catches op will vary. It can be argued that they are not being sustained, and that ...

   Science Journal Paper : Selected Scientific Papers, SC-CAMLR-SSP/4 (Selected Scientific Papers, SC-CAMLR-SSP/4) : 299-322 : Auteur(s): Gulland, J.A.

6. Spatial distribution of management measures, Antarctic krill catch and Southern Ocean bioregions: implications for conservation planning

   be used to prioritise protection for bioregions that are currently under-represented in marine ... important differences between pelagic bioregions in terms of the fraction that was open to fishing, and the ... protected areas (MPAs). However, conservation planning should take account of uncertainties that result from ... , to ensure that protected areas can be selected to meet conser- vation objectives with minimal cost ... MPAs, stating that: ‘CCAMLR MPAs shall be established on the basis of the best available scientific ... ecosystem processes to determine the different regions and habitat types that must be represented (e.g ... that can meet the defined conservation objectives with minimal displacement of these activities. In ...

   Science Journal Paper : CCAMLR Science, Volume 20 (CCAMLR Science, Volume 20) : 1–19 : Auteur(s): Grant, S.M., S.L. Hill and P.T. Fretwell

7. Estimates of circumpolar abundance of Antarctic krill based on recent acoustic density measurements

   tonnes- at the low end of values that have been suggested in the past. The differences between our ... estimates and others can be explained by a number of factors such as: an underestimation of the range or the ... value used in the past. The seasonal and local consequences of large catch limits will have to be taken ... statistical divisions as management areas will have to be considered. File:  05nicol-etal.pdf ... that have been suggested in the past. The differences between our estimates and others can be ... result, and that the stratified krill biomass estimates may be similarly realistic, particularly for ... swarms. Underwater photographs of subsurface aggregations of krill reveal that they can be closely ... indicate that the calculated precautionary catch limit is likely to be higher than the current 1.5 ...

   Science Journal Paper : CCAMLR Science, Volume 7 (CCAMLR Science, Volume 7) : 87–99 : Auteur(s): Nicol, S., A.J. Constable and T. Pauly

8. Use of the Leslie stock depletion model for the assessment of local abundance of Patagonian toothfish (Dissostichus eleginoides)

   presents a re-working and synthesis of previous analyses to examine whether declines in CPUE can be ... in localised areas for periods of at least three days. The results suggest that there is greater ... consistent signal in the data for the depletion model to be used to estimate local abundance. A number of ... size, and that this reduction would be indicated by a significant decline in an abundance index with ... vessels which overlapped with the series being analysed. Note that no detailed position information was ... the analysis, even though it is possible that some of these may have overlapped with the selected ... to be used in the model as a proxy for numbers of fish. For instance, it must be assumed that there ...

   Science Journal Paper : CCAMLR Science, Volume 3 (CCAMLR Science, Volume 3) : 55–77 : Auteur(s): Parkes, G., C.A. Moreno, G. Pilling and Z. Young

9. Investigations of required sampling regimes for environmental parameters

   and pressure. Sampling daily maxima and minima would be sufficient to detect a 2 to 3°C change in ... monthly mean temperature over two years with a significance α of 0.05 and a power P of 0.8. Sampling wind ... speed continuously or as daily maxima and minima would be sufficient to detect a 10 to 20% change in ... minima would be sufficient to detect a 2 to 3°C change in monthly mean temperature over two years with a ... strategies for weather conditions should be defined so that changes in environmental parameters can be ... confidently identified. Sample size and frequency should be chosen so that ex, the probability of making a ... Working Group (1989) suggested that sampling strategies should be able to detect a 10% or 20% change in a ...

   Science Journal Paper : Selected Scientific Papers, SC-CAMLR-SSP/7 (Selected Scientific Papers, SC-CAMLR-SSP/7) : 561–573 : Auteur(s): Agnew, D.J.

10. A simulation study of the method of deriving natural mortality rate using data for Champsocephalus gunnari in Subarea 48.3

    (determined by VPA) and fishing effort is described. The intersect of this regression must be equal to zero if ... been correctly chosen. Data for Champsocephalus gunnari in Subarea 48.3 are used to show that the ... estimate of the intercept of the regression is other than zero. A bias in the intercept will be positive if ... that the scientific justification for using the method of Gasyukov and Dorovskikh (1990) would be ... it will be reasonable to apply the statistical null hypotheses that this factor is equal to zero ... . It should be noted that steps (iv) and (v) can be accomplished by a number of methods. Mean weighted ... algorithm of simple and that of functional regressions can be used (Ricker, 1975). 3. SIMULATION ...

    Science Journal Paper : Selected Scientific Papers, SC-CAMLR-SSP/8 (Selected Scientific Papers, SC-CAMLR-SSP/8) : 69–83 : Auteur(s): Gasyukov, P.S. and R.S. Dorovskikh

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