Résultats de la recherche
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Krill population biology during the 1991 Chilean Antarctic krill fishery
size from 1.5 to 3 cm). Two subsamples of 100 specimens each were taken from 50 samples and analysed ... . The fishing ground was divided into two areas: Area A, north of the South Shetland Islands; and Area B ... 419 hauls. In Area A, a unimodal size frequency distribution was found; the size range was between 30 ... and 55 mm TL, with a mean TL of 45 mm for females and 48 mm for males. A very weak mode for juvenile ... between 30 and 55 mm TL, with a mean TL of 45 mm for females and 48 mm for males. A very weak mode for ... other (modal length 32 mm) for juvenile specimens between 20 and 39 mm TL. Females comprised 47.1 ... length mode of specimens between 30 and 55 mm TL, a mean TL of 45 mm for females and 48 mm for males ... ) for juvenile specimens (sex undetermined) between 20 and 39 mm TL (Figure 4). Females were also more ...
Science Journal Paper : Selected Scientific Papers, SC-CAMLR-SSP/9 (Selected Scientific Papers, SC-CAMLR-SSP/9) : 223–235 : Auteur(s): Mujica R., A., E. Acuña S. and A. Rivera O.
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The sensitivity of multiple output statistics to input parameters in a krill–predator–fishery ecosystem dynamics model
strategic frameworks for assessing uncertainty in ecosystem dynamics models. Such models have been used ... within CCAMLR to evaluate options for managing the Antarctic krill fishery in the Scotia Sea and southern ... Drake Passage. The model analysed here required 2 311 input values for each of four scenarios and ... to identify the important statistics for consideration when assessing uncertainty in ecosystem ... , including one each for krill (productivity) and fishery performance (services) and two (health and ... described in Hill et al. (2007a, 2007b), as an example of good practice for addressing sev- eral types of ... model outputs, and provides an objective basis for targeting data collection and modelling effort to ... shorter than a year) 2 There are, in fact, 29 arguments for the main function. Eleven of these are ...
Science Journal Paper : CCAMLR Science, Volume 20 (CCAMLR Science, Volume 20) : 97–118 : Auteur(s): Hill, S.L. and J. Matthews
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Distribution of krill (Euphausia superba Dana) catches in the South Shetlands and South Orkneys
, foraging ranges and population sizes from the literature are used to show that for some years catches ... South Orkneys Abstract / Description: A set of concentric zones of 20 km width was defined around ... . Krill catches in these zones are shown to have a consistent pattern in Subarea 48.1 but an unpredictable ... in all years 1988 to 1991. In 1987, 1988 and 1991, 75% of the catch in Subarea 48.2 between December ... for Subareas 48.1 and 48.2. 100 90 80 .c. 70 J:! tfJ 0 () 50 -0 40 a-e 30 20 10 ... was similar for each of the years examined whereas that for Subarea 48.2 changed each year (Figures 3 ... , accounting for 45% of the total krill consumed each year. Crabeater seals (Lobodon carcinophagus), which are ... 290 data given for each CCAMLR fine-scale square (1 0 longitude by 30' latitude) for each quarter ...
Science Journal Paper : Selected Scientific Papers, SC-CAMLR-SSP/9 (Selected Scientific Papers, SC-CAMLR-SSP/9) : 287–303 : Auteur(s): Agnew, D.J.
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Significant intra-annual variability in krill distribution and abundance at South Georgia revealed by multiple acoustic surveys during 2000/01
March 2001 (late-season). The surveys were the first in a newly planned five-year series of observations ... designed to complement and extend an existing time series regularly maintained by the British Antarctic ... indices for top level predators to be compared to prey availability at more appropriate time-scales than ... Survey since 1996 (and on a more ad hoc basis since the early 1980s). We hoped that conducting several ... planned fi ve-year series of observations designed to complement and extend an existing time series ... survey strategy for the new fi ve-year series addresses these temporal shortcomings by including ... two acoustic surveys were conducted at South Georgia in the same season. In October 1997 an ... to this, but on a more ad hoc basis (see Brierley et al., 1999 for a summary of all surveys). In ...
Science Journal Paper : CCAMLR Science, Volume 9 (CCAMLR Science, Volume 9) : 71–82 : Auteur(s): Brierley, A.S., C. Goss, S.A. Grant, J.L. Watkins, K. Reid, M. Belchier, I. Everson, M.J. Jessop, V. Afanasyev and J. Robst
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Scientific observations in CCAMLR fisheries – past, present and future
observers on board fishing vessels has assumed prominence in the collection of essential data for fisheries ... / Description: CCAMLR has the primary competency for managing fishing south of the Antarctic Polar Front ... designed to gather and validate fishery-related information essential for assessing the status of target ... strategy has often had to deal with incomplete and uncertain information on affected resources. Fishery ... Measure 41-01 (2004), paragraph 7) (see CCAMLR, 2004b). 0 10 20 30 40 50 60 1996 1997 1998 1999 ... least two scientifi c observers per vessel was introduced for exploratory fi sheries for Dissostichus ... data for an entire stock or fi shery over the stock’s entire distribution. Such programs often lack ... information essential for assessing the status of target species as well as the impact of fi shing on ...
Science Journal Paper : CCAMLR Science, Volume 12 (CCAMLR Science, Volume 12) : 81–98 : Auteur(s): Sabourenkov, E.N. and E. Appleyard
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Preliminary appraisal of Antarctic fish selection by the 32/36 bottom trawl combined with various codends
of both tape codends were much better. It was found that an optimum mesh size of this codend for ... material used for their construction, incorrectly chosen mesh size, and certain morphological features of ... some Antarctic fish, which make it difficult for them to escape from the codend. Selectivity properties ... selection of Antarctic icefish and bumphead notothenia ranges from 60 to 100 mm. For other Antarctic fish ... were much better. It was found that an optimum mesh size of this codend for selection of Antarctic ... calculated as a mean from 30 measurements. For investigations, only those tows were selected which ... size was 123.6 mm, after the first two and after 30 hours of the codend exploitation its mesh size ... ogives were drawn for each of the two phases of the experiment (Figure 16). The analysis of both ...
Science Journal Paper : Selected Scientific Papers, SC-CAMLR-SSP/4 (Selected Scientific Papers, SC-CAMLR-SSP/4) : 1-48 : Auteur(s): Zaucha, J.
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Analysis of results from demersal fish surveys at South Georgia, undertaken by the United Kingdom and the USSR, January and February 1990
these large hauls were considered in the analysis. No ideal method was found for incorporating the large ... consist of one representative bottom trawl with the net fishing for 30 minutes on the bottom. The net ... difficulty in the area to the southern part of the west shelf (squares 19 and 20). The reports of the two ... series. All hauls were intended to last for 30 minutes at a speed of 3 to 3.5 knots. Hauls were ... approach. The other two approaches provide for much larger sample sizes within each grouping and hence ...
Science Journal Paper : Selected Scientific Papers, SC-CAMLR-SSP/7 (Selected Scientific Papers, SC-CAMLR-SSP/7) : 223–254 : Auteur(s): (Report of a Joint UK/USSR Workshop, 23 to 27 July 1990)
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Food consumption by predators in a CCAMLR integrated study region
/ Description: A detailed description of the structure and mode of operation of a model for estimating food ... Georgia Integrated Study Region and incorporates new features, allowing for seasonal variation in predator ... existing empirical data on breeding population size, diet, activity-specific energy requirements and ... two breeding attempts in three years at South Georgia. Thus the estimation procedure is based on an ... energy requirement on each day of the year for each species in the community. Because the sizes ... activity cycle (365 for most species, 730 for species whose cycle lasts two years, and 1 095 for king ... the user for two file names, some dates (again day 1 is 1 September) and the type of graphical output ...
Science Journal Paper : Selected Scientific Papers, SC-CAMLR-SSP/7 (Selected Scientific Papers, SC-CAMLR-SSP/7) : 489–519 : Auteur(s): Croxall, J.P., C. Ricketts and A.G. Wood
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Biological characteristics of Antarctic fish stocks in the southern Scotia Arc region
sexual maturity and length at first spawning in Champsocephalus gunnari was one year later on the ... from 1977/78 to 1989/90, and was in its heyday from 1977/78 to 1981/82. Except for Elephant Island, the ... ) Program carried out two extensive surveys around Elephant Island and the lower South Shetland Islands in ... takes one year or more, whereas in others gonad maturation was completed within one season. Length at ... budgets for the entire year can be compiled. Emphasis should also be placed on studies on the macro ... included for comparison (Table 2). Readers are also referred to an extensive collection of length-weight ... mostly around the South Orkney Islands in March 1999 (Table 4). The material for the other two areas ... of 20-30 m off the southwest coast of Elephant Island by a 3 m beam trawl. Early juveniles of other ...
Science Journal Paper : CCAMLR Science, Volume 7 (CCAMLR Science, Volume 7) : 1–41 : Auteur(s): Kock, K.-H., C.D. Jones and S. Wilhelms
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Low genetic diversity in the Antarctic toothfish (Dissostichus mawsoni) observed with mitochondrial and intron DNA markers
with mitochondrial and intron DNA markers Abstract / Description: Two molecular methods, mitochondrial ... , 1984; Williams et al., 1994), but DNA analyses showed evidence for two genetic units, one around ... air dried and resuspended in 40 µl sterile water and stored at –20°C. Two classes of markers, mtDNA ... performed in 20 μl volumes for a minimum of 4 h, following the manufacturer’s recommendations (New England ... Sequencing Kit according to the manufacturer’s directions (Applied Biosystems Inc., USA) and run on an ABI ...
Science Journal Paper : CCAMLR Science, Volume 12 (CCAMLR Science, Volume 12) : 43–51 : Auteur(s): Smith, P.J. and P.M. Gaffney