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1. Length-based assessment for mackerel icefish (Champsocephalus gunnari) at South Georgia

   Georgia Abstract / Description:  The current CCAMLR assessment method for mackerel icefish ... (Champsocephalus gunnari) in Subarea 48.3 employs the CCAMLR mixture analysis program (CMIX) and generalised yield ... the given harvest control rule to set a two-year total allowable catch (TAC). One issue is the ... accurate identification of age cohorts from the survey data. In this paper a length-based approach is ... define numbers-at-age in the population. Assuming a closed population (i.e. with no recruit- ment) the ... which there are P times P) to generate the transition matrix Γ. Note also that no error distribution ... estimated numbers-at-length are assumed to be the total closed population abundance (i.e. there is no ... no systematic differences between results from the proposed length-based method and the current ...

   Science Journal Paper : CCAMLR Science, Volume 17 (CCAMLR Science, Volume 17) : 129–137 : Autor(es): Hillary, R.M., C.T.T. Edwards, R.E. Mitchell and D.J. Agnew

2. Catch per unit effort and proportional recruitment indices from Japanese krill fishery data in Subarea 48.1

   . CPUE (catch/towing volume) in the Livingston Island area showed a decreasing trend during the study ... period. The use of different fishing strategies in response to a demand for higher product quality and a ... general decrease in krill density in the study area were considered as possible reasons for this. On the ... other hand, CPUE in the Elephant Island area showed greater interannual variation without any trend ... ), but no significant trend in the Elephant Island area (T = -0.200, n = 11, p = 0.39). DISCUSSION ... no clear trend was observed in the search for krill aggregations before deploying Elephant Island ... . CPUE (catch/towing volume) in the Livingston Island area showed a decreasing trend during the study ... period. The use of different fishing strategies in response to a demand for higher product quality and a ...

   Science Journal Paper : CCAMLR Science, Volume 4 (CCAMLR Science, Volume 4) : 47–63 : Autor(es): Kawaguchi, S., T. Ichii and M. Naganobu

3. Calibration of an acoustic echo-integration system in a deep tank, with system gain comparisons over standard sphere material, water temperature and time

   outlines the theory and procedures for calibrating an echo integration acoustic system with a standard ... sphere. It presents the results of an extensive calibration of a Simrad EK500 scientific echosounder with ... length (0.1, 0.3 and 1.0 ms), target depth (0.8 to 7.5 m), and time (149 days). The total range in TS ... gain, including the effects of temperature, standard sphere and time, is 2.9 dB. Gain values calibrated ... independent of orientation, and no additional electronic equipment is required (Blue, 1984). Furthermore, the ... be performed with no effect from the water column boundaries so that only spherical waves reflecting ... . Therefore, if no data were collected exactly on axis, the nearest data to the axis were used after being ... parameter alone, can be no better than ±0.5 dB. At greater ranges, the biases are proportionally larger ...

   Science Journal Paper : Selected Scientific Papers, SC-CAMLR-SSP/9 (Selected Scientific Papers, SC-CAMLR-SSP/9) : 127–144 : Autor(es): Demer, D.A. and R.P. Hewitt

4. Variations in condition indices of mackerel icefish at South Georgia from 1972 to 1997

   1997 Abstract / Description:  Mackerel icefish (Champsocephalus gunnari) are widespread on the South ... Georgia shelf, Antarctica, and have been fished commercially since the early 1970s. They are known to feed ... predominantly on krill. An index of condition which uses the ratio of the measured total mass to the estimated ... mass is shown to provide a good indicator of local krill density. The index is likely to be little ... fur seal pup weight in 1973, a year when there were no reports of krill scarcity, to that on the ... penguins on the shore of Cumberland Bay, South Georgia, in March 1978. In 1978/79, when penguin breeding ... density. There were no krill density estimates during 1977 and 1978, so we infer that the changes in ... the breeding site. The foraging trip and diet parameters integrate over these same scales but in ...

   Science Journal Paper : CCAMLR Science, Volume 8 (CCAMLR Science, Volume 8) : 119–132 : Autor(es): Everson, I. and K.-H. Kock

5. Can we use discriminant function analysis to sex penguins prior to calculating an index of a morphometric characteristic?

   discriminant analysis can be used to determine the sex of individuals, it is only able to correctly sex a ... difference between the real mean characteristic for a sex, and the apparent mean derived by sexing the birds ... using discriminant analysis. When discriminant functions are able to correctly determine the sex of ... birds with greater than 80% success, the difference between the true and apparent mean is likely to be ... males and females, and these often overlap. Whilst discriminant analysis can be used to determine the ... normal distributions are used to show that there is a difference between the real mean characteristic ... for a sex, and the apparent mean derived by sexing the birds using discriminant analysis. When ... discriminant functions are able to correctly determine the sex of birds with greater than 80% success, the ...

   Science Journal Paper : Selected Scientific Papers, SC-CAMLR-SSP/9 (Selected Scientific Papers, SC-CAMLR-SSP/9) : 259–272 : Autor(es): Agnew, D.J.

6. An assessment of CCAMLR measures employed to mitigate seabird mortality in longlining operations for Dissostichus eleginoides around South Georgia

   the effectiveness of measures employed by CCAMLR to mitigate seabird mortality. Following an agreement ... between the Governments of the United Kingdom and Chile, a UK observer was placed aboard a Chilean ... longliner, the BF Cisne Verde, fishing in CCAMLR Subarea 48.3 during the 1996/97 season. In this study 61 ... lines were laid from March to May 1997 using the Spanish double-line method. In accordance with CCAMLR ... intervals along the line, all deck lights were extinguished and no offal was discarded during setting. A ... several species of albatross have been reported from breeding sites in the Southern Ocean, and have been ... requested otherwise. It broke once while in use, and was replaced for the following set. No offal was ... for each day's hauling. Periods were selected in one of two ways: haphazardly over the line when no ...

   Science Journal Paper : CCAMLR Science, Volume 5 (CCAMLR Science, Volume 5) : 217–230 : Autor(es): Ashford, J.R. and J.P. Croxall

7. Assessments of by-catch in trawl fisheries at Heard and McDonald Islands

   / Description:  This paper assesses the potential for the commercial trawl fisheries in the Heard Island area ... (Statistical Division 58.5.2) to significantly affect, in the long term, spawning biomass of three taxa caught ... skates). The long-term annual yield for each of the three taxa was estimated using the generalised yield ... model (GYM) used by the CCAMLR Working Group on Fish Stock Assessment (WG-FSA). Input data included ... 5.18 to 5.26). This was necessary because no information was available on the actual magnitude of ... the probability of depletion below 0.2 of the median pre-exploitation spawning biomass be no greater ... by-catch is no greater than 5% of the total catch, however, would exclude many areas from ... fishing site and at times making operations very difficult. In the C. gunnari fishery, C. rhinoceratus ...

   Science Journal Paper : CCAMLR Science, Volume 5 (CCAMLR Science, Volume 5) : 231–243 : Autor(es): Constable, A.J., R. Williams and W.K. de la Mare

8. Results of fish stock assessment survey, South Georgia region, November - December 1986

   between 29 November and 17 December 1986 by the R.V. Professor Siedlecki using a Polish B-454 otter trawl ... standard (e.g., relatively little or no gear damage) (Figure 1). In the Shag Rocks region, 13 tows were ... December 1986 by the R.V. Professor Siedlecki using a Polish B-454 otter trawl. Biomass was estimated ... parecieron ser menores en 1986/87 que aquel1as de 1984/85, aunque no en un orden de magnitud. Las ... abundancias de Notothenia qibbertfrons y Chaenocephalus aceratus, tanto las estimadas en este estudio, como ...

   Science Journal Paper : Selected Scientific Papers, SC-CAMLR-SSP/4 (Selected Scientific Papers, SC-CAMLR-SSP/4) : 143-183 : Autor(es): Gabriel, W.L.

9. Age, growth and mortality of Patagonian toothfish (Dissostichus eleginoides) caught off Kerguelen

   otoliths from reference collections were used to measure precision; relative bias for the age data was ... showed discrepancies due to gear-specific catchability, or differences in the available population with ... partially funded by the United States National Science Foundation under grant No. NSF-OPP- 0231919. They ... , growth and mortality of At- lan tic croaker, Micropogonias undulatus, in the Chesapeake Bay region, with ... for the age data was estimated to be –0.6 years and residual variance 2.9. Age distributions of ... in the available population with depth or season. Age–length keys were constructed for use in ...

   Science Journal Paper : CCAMLR Science, Volume 12 (CCAMLR Science, Volume 12) : 29–41 : Autor(es): Ashford, J., G. Duhamel, C. Jones and S. Bobko

10. Results of fish stock assessment survey, South Georgia, December 1987 - January 1988

    Abstract / Description:  Commercial fish stocks around South Georgia have been declining since the early ... complements earlier surveys in the same area and showed that most of the stocks are continuing to decline ... . Notothenia rossii is showing no signs of recovery and Champsocephalus gunnari is likely to continue declining ... hundred and four occurred along the South Georgia coast and were considered standard (e.g. little or no ... (Figure 3a). The first and second modes were present in both 1986/87 and 1987/88, but no discernable mode ... size class during 1986/87. This size class was absent from the 1987/88 population and no fish over 40 ... no substantial recruitment. It is not clear from the length frequency distribution (Figure 7a) if ...

    Science Journal Paper : Selected Scientific Papers, SC-CAMLR-SSP/5 – Part II (Selected Scientific Papers, SC-CAMLR-SSP/5 – Part II) : 19-52 : Autor(es): McKenna, Jr., J.E. and S.B. Saila

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