Résultats de la recherche

1. Maximum entropy reconstructions of krill distribution and estimates of krill density from acoustic surveys at South Georgia, 1996–2000

   × 0.5 km cells in each box, taking explicit account of the spatial relationship between densities in the ... observed data. Despite some very large interannual and regional differences in mean krill density, the ... survey boxes (dimensions 80 km × 100 km) north of South Georgia. The reconstructions were generated from ... line-transect acoustic survey data gathered in the boxes during austral summers from 1996 to 2000 ... infer- ence of the mean krill density (g m-2) in each of the 32 000 0.5 × 0.5 km cells within each ... been determined at approximately 0.5 km intervals along each of the ten 80 km transects in each box ... to infer the most probable krill density for each of the 32 000 0.5 × 0.5 km cells in each box ... , taking explicit account of the spatial relationship between densities in the observed data. Despite ...

   Science Journal Paper : CCAMLR Science, Volume 10 (CCAMLR Science, Volume 10) : 91–100 : Auteur(s): Wafy, M.H., A.S. Brierley, S.F. Gull and J.L. Watkins

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

   different guidelines under more realistic population models, taking account of the objectives set out in ... / Description:  The concept of ‘Maximum Sustainable Yield’ (MSY) has provided a useful guideline for resource ... management under the assumptions of a simple population model and simple objectives. This paper explores ... Article II of the CCAMLR Convention. The criteria will depend on whether the main concern is with ... associated species. From this it may be possible to determine boundaries to the extent of change in mean ... realistic population models, taking account of the objectives set out in Article 11 of the CCAMLR ... comprehension, and reasonable correspondence to the behaviour of resources under exploitation. In the 1950s ... and 1960s it served a very useful purpose in bringing an understanding of the broad principles of ...

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

3. Validation of sink rates of longlines measured using two different methods

   sight behind waves or in congregations of seabirds before the target depth was reached. No TDRs were ... of the ground line – IW-50 lines) were measured during commercial fishing operations using two ... behind the vessel, i.e. out of the observer’s sight, when they reached the target depth. Bottles had a ... measure sink rates to depths of more than 2 m down to the seabed. A major advantage of the TDRs is the ... improve the manuscript. References CCAMLR. 2002. Schedule of Conservation Measures in Force, 2002/03 ... seabird mortality in demersal longline fi shing operations, the sink rate of the longlines was identifi ... recording the water-entry time of TDRs. Based on TDR data, the differences in sink rates to various target ... depths and the variation in sink rates of longlines over four depth increments with increasing distance ...

   Science Journal Paper : CCAMLR Science, Volume 11 (CCAMLR Science, Volume 11) : 179–187 : Auteur(s): Wienecke, B. and G. Robertson

4. Results of fish larvae sampling by means of fine-meshed samplers attached to a bottom trawl

   bottom trawl Abstract / Description:  Fine-meshed samplers were attached to the top of a bottom trawl in ... order to provide information on the composition, distribution and abundance of Antarctic fish larvae in ... sized meshes for sampling larvae in the bottom zone and the resistance of the samplers to damage during ... , more vulnerable to damage. The nets were more effective in sampling when attached to the top of the ... -meshed samplers were attached to the top of a bottom trawl in order to provide information on the ... composition, distribution and abundance of Antarctic fish larvae in the near-bottom zone, which is usually ... not sampled using plankton nets. The efficiency of various sized meshes for sampling larvae in the ... nets were more effective in sampling when attached to the top of the trawl belly, not to the codend. A ...

   Science Journal Paper : Selected Scientific Papers, SC-CAMLR-SSP/5 – Part II (Selected Scientific Papers, SC-CAMLR-SSP/5 – Part II) : 69-86 : Auteur(s): Ślósarczyk, W. and I. Wójcik

5. Distribution of mackerel icefish (Champsocephalus gunnari) (Channichthyidae) around South Georgia at various stages of its life cycle

   cm in length) were mainly found in the southern part of the study area, immature fish (15–25 cm) in ... the east and southwest, and adults (25–39 cm) in the north. The distribution of C. gunnari changes ... vertical migrations. Variations found in the depth distribution of C. gunnari relate both to fish length ... South Georgia at various stages of its life cycle Abstract / Description:  The distribution of mackerel ... age–length distribution and mean length of 2- to 4-year-old fi sh in the western and Shag Rocks ... (<15 cm in length) were mainly found in the southern part of the study area, immature fi sh (15–25 cm ... ) in the east and southwest, and adults (25–39 cm) in the north. The distribution of C. gunnari ... (>40 cm) did not undertake vertical migrations. Variations found in the depth distribution of C ...

   Science Journal Paper : CCAMLR Science, Volume 9 (CCAMLR Science, Volume 9) : 49–69 : Auteur(s): Frolkina, Zh.A

6. 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 ... survey of the South Atlantic in January 2000 may result in an effective biomass which is greater than the ... value used in the past. The seasonal and local consequences of large catch limits will have to be taken ... density measurements Abstract / Description:  The total circumpolar abundance of Antarctic krill ... the digitised map results in an overall mean biomass of 92.1 million tonnes (Table 1). Using the ... tonnes - the mean value derived from estimates of known density. Krill biomass in the southern Atlantic ... effectively underestimated the krill biomass by a factor of three, so the new survey of the South Atlantic in ... distribution maps produced in the Discovery Reports (Marr, 1962; Mackintosh, 1973) support modern ideas of ...

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

7. Differentiation of independent populations of Antarctic krill

   . superba in the Southern Ocean subdivided into several independent sub-populations. The number of these sub ... :  Several countries have recently shown an interest in commercial krill fishing. An understanding of krill ... of recent studies in genetic and morphophysiological variability of krill and Antarctic water ... circulation. On the basis of the review, it is suggested that there is probably one composite population of E ... review, it is suggested that there is probably one composite population of E. superba in the Southern ... OF THE ANTARCTIC KRILL In recent years, several countries (Poland, Federal Republic of Germany ... , Japan, Chile and some others) have shown their interest in the problem of utilization of the resources ... has been estimated for the entire area of its distribution, while it is fished only in particular ...

   Science Journal Paper : Selected Scientific Papers, SC-CAMLR-SSP/3 (Selected Scientific Papers, SC-CAMLR-SSP/3) : 275-281 : Auteur(s): USSR

8. Midwater trawl catchability as an aspect of a quantitative assessment of krill biomass conducted using a trawl census survey

   variable which depends on both the behavioural and distributional characteristics of the target species and ... midwater trawls and small research trawls, in this case using an Isaacs-Kidd trawl, demonstrated the ... futility of using the latter for trawl census survey biomass assessments due to their highly variable ... can facilitate selecting the optimal construction of commercial midwater trawls. Assessments of the ... , specific biomass (density) of krill in the catch is expressed in g/m2 or g/m3 at the point of trawling ... by the coefficient of variation of the catch per haul (Kq = aq/mq). Difficulties in estimating the ... catchability of research trawls such as the Isaacs-Kidd is generally known to be equal to 1.0, while in the ... case of a commercial trawl catchability P = 1.0 is applied to the fine-meshed attachment in the trawl ...

   Science Journal Paper : Selected Scientific Papers, SC-CAMLR-SSP/8 (Selected Scientific Papers, SC-CAMLR-SSP/8) : 257–272 : Auteur(s): Kasatkina, S.M.

9. Sexing of adult Adélie penguins by discriminant analysis of morphometric measurements

   determine the sex of Adélie penguins. A sample of 46 adult birds was taken for measurement from the breeding ... population at Stranger Point (King George/25 de Mayo Is., South Shetland Islands). The sex of each bird had ... been determined earlier by means of observing the birds' breeding behaviour (first incubation ... shift). It was found that the combination of flipper breadth, bill depth and length of the middle toe ... for discriminating between sexes. In practice, this means that the sex of an individual Adelie ... formula, and comparing the results with the constants shown in Table 1. To verify the valIdity of this ... robustus. Ibis 113: 1-7. WARHAM, J. 1975. The crested penguins. In: STONEHOUSE, B. (Ed.). The Biology of ... determine the sex of Adelie penguins. A sample of 46 adult birds was taken for measurement from the ...

   Science Journal Paper : Selected Scientific Papers, SC-CAMLR-SSP/7 (Selected Scientific Papers, SC-CAMLR-SSP/7) : 543–549 : Auteur(s): Scolaro, J.A., Z.B. Stanganelli, H. Gallelli and D.F. Vergani

10. On assessment of Bertalanffy growth equation parameters and instantaneous natural mortality rate of South Georgia mackerel icefish

    icefish (Champsocephalus gunnari) for 1965 to 1987 is presented. The results enable the calculation of ... reliable weight-length equations for males and females by season and the verification of parameters for the ... Bertalanffy growth equation. Mean value of natural mortality rate was estimated at 0.55. File:  03-Frolkina ... Paper Title:  On assessment of Bertalanffy growth equation parameters and instantaneous natural ...

    Science Journal Paper : Selected Scientific Papers, SC-CAMLR-SSP/6 (Selected Scientific Papers, SC-CAMLR-SSP/6) : 29–36 : Auteur(s): Frolkina, Zh.A. and R.S. Dorovskikh

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