Résultats de la recherche

1. Using ecosystem monitoring data to detect impacts

   Paper Title:  Using ecosystem monitoring data to detect impacts Abstract / Description:  The ... purpose of ecosystem monitoring programs is to indicate the state of ecosystems and whether they have been ... using monitoring data with no control sites. These methods assess either (i) the expected probability of ... an observed value in an unimpacted system, or (ii) the frequency of values below a fixed reference ... pn after 1991, and it rapidly exceeds the 1988 to 1989 value. Risks Metrics of risk indicate ... United Kingdom Email – sih@bas.ac.uk Abstract The purpose of ecosystem monitoring programs is to ... indicate the state of ecosystems and whether they have been impacted by activities such as fishing. This ... sites. These methods assess either (i) the expected probability of an observed value in an unimpacted ...

   Science Journal Paper : CCAMLR Science, Volume 17 (CCAMLR Science, Volume 17) : 197–212 : Auteur(s): Hill, S.L., J. Forcada, P.N. Trathan and C.M. Waluda

2. Estimating confidence intervals for fish stock abundance estimates from trawl surveys

   estimates of abundance obtained from trawl surveys conducted by means of the swept area method, using ... likelihood ratios from Aitchison's delta distribution. Simulation tests of the method show that unbiased ... estimates of density and biomass can be obtained and that the estimated confidence intervals have close to ... the nominal coverage probability. Performance deteriorates in cases where few of the hauls contain ... by means of the swept area method, using likelihood ratios from Aitchison's delta distribution ... . Simulation tests of the method show that unbiased estimates of density and biomass can be obtained and that ... the estimated confidence intervals have close to the nominal coverage probability. Performance ... deteriorates in cases where few of the hauls contain fish and the coefficient of variation (CV) is high. The ...

   Science Journal Paper : CCAMLR Science, Volume 1 (CCAMLR Science, Volume 1) : 203–207 : Auteur(s): de la Mare, W.K

3. Modelling krill recruitment

   observed values of the mean proportion of recruits and its variance to model recruitment in a krill ... population in terms of numbers of recruits. The method includes the calculation of natural mortality and ... other parameters consistent with the observed proportional recruitment parameters. A procedure is given ... for generating families of recruitment functions which are consistent with the statistical uncertainty ... , Australia Abstract A method is developed for using observed values of the mean proportion of recruits ... and its variance to model recruitment in a krill population in terms of numbers of recruits. The ... method includes the calculation of natural mortality and other parameters consistent with the observed ... which are consistent with the statistical uncertainty in the observed recruitment parameters. Resume ...

   Science Journal Paper : CCAMLR Science, Volume 1 (CCAMLR Science, Volume 1) : 49–54 : Auteur(s): W.K. de la Mare

4. Toothfish, Dissostichus eleginoides, at South Georgia

   Paper Title:  Toothfish, Dissostichus eleginoides, at South Georgia Abstract / Description:  The ... that the exploited fish are senescent and not contributing to the breeding population (CCAMLR-VIII ... , paragraph 106). Histological examination of the gonads of a small sample of fish taken from a commercial ... longliner in January 1990 indicates that the fish are sexually mature and, at the time of sampling, are ... SOUTH GEORGIA I. Everson and S. Campbell* Abstract The Dissostichus eleginoides fishery at South ... Georgia has expanded greatly in recent years. It has been claimed that the exploited fish are senescent ... and not contributing to the breeding population (CCAMLR-VIII, paragraph 106). Histological ... examination of the gonads of a small sample of fish taken from a commerciallongliner in January 1990 ...

   Science Journal Paper : Selected Scientific Papers, SC-CAMLR-SSP/7 (Selected Scientific Papers, SC-CAMLR-SSP/7) : 255–261 : Auteur(s): Everson, I. and S. Campbell

5. Age and growth of Antarctic euphausiacea (crustacea) under natural conditions

   Abstract / Description:  Five species of Antarctic euphausiid crustaceans were studied from the Antarctic ... Peninsula and the south-eastern Weddell Sea. Life spans range from two years for Euphausia frigida to six ... years for the krill Euphausia superba. Growth in length and weight was calculated by non-linear ... regressions. No difference in growth of krill was observed between the Antarctic Peninsula area and the ... Five species of Antarctic euphausiid crustaceans were studied from the Antarctic Peninsula and the ... south-eastern Weddell Sea. Life spans range from two years for Euphausia frigida to six years for the ... difference in growth of krill was observed between the Antarctic Peninsula area and the eastern Weddell Sea ... . Former opinions that differ are discussed. Seasonal growth was re-analyzed for the species Euphausia ...

   Science Journal Paper : Selected Scientific Papers, SC-CAMLR-SSP/4 (Selected Scientific Papers, SC-CAMLR-SSP/4) : 369-370 : Auteur(s): Siegel, V.

6. Trawl selectivity for Champsocephalus gunnari

   selectivity for mackerel icefish (Champsocephalus gunnari L.), were collected in 1981 in the South Georgia ... area. The trawl bags tested were made of net webbing with 3.1 mm twine and 88.2 mm mesh size. Trawling ... speed was 3.5 knots. Icefish comprised 90 to 100% of catches. The logistic selectivity curves were ... calculated using the collected data. It was found that the selectivity factor for 88.2 mm mesh size was 2.81 ...

   Science Journal Paper : Selected Scientific Papers, SC-CAMLR-SSP/6 (Selected Scientific Papers, SC-CAMLR-SSP/6) : 69–75 : Auteur(s): Efanov, S.F., G.E. Bidenko and V.A. Boronin

7. Reproductive performance of seabirds and seals at South Georgia and Signy Island, South Orkney Islands, 1976-1987: implications for Southern Ocean monitoring studies

   / Description:  Aspects of the reproductive performance over the last decade of black-browed, grey-headed and ... reviewed. Breeding success of the wandering albatross, which breeds in winter and eats fish and squid, has ... remained constant, while population size has declined gradually but significantly. The other species at ... species; circumstantial evidence relating this to reduced availability of krill is discussed. The ... and P. Rotheryl (United Kingdom) Abstract Aspects of the reproductive performance over the last ... , South Orkney Islands, are summarised and reviewed. Breeding success of the Wandering Albatross, which ... gradually but significantly. The other species at South Georgia, which breed in summer and feed ... reduced availability of krill is discussed. The fluctuations in reproductive performance of the krill ...

   Science Journal Paper : Selected Scientific Papers, SC-CAMLR-SSP/4 (Selected Scientific Papers, SC-CAMLR-SSP/4) : 445-447 : Auteur(s): Croxall, J.P., T.S. McCann, P.A. Prince and P. Rothery

8. Size at sexual maturity of Patagonian toothfish (Dissostichus eleginoides)

   (Dissostichus eleginoides) caught in the commercial fishery within Subarea 48.3. The results for 1996 indicate ... that L m50 occurs at 78.5 cm total length for male and 98.2 cm for female fish. In 1997 the results for ... male fish were essentially the same. For female fish there is evidence that in 1997 a significant ... bias leading to the overestimation L m50 of  calculated by conventional methods. Further analysis ... the commercial fishery within Subarea 48.3. The results for 1996 indicate that Lm50 occurs at 78.5 cm ... total length for male and 98.2 cm for female fish. In 1997 the results for male fish were essentially ... the same. For female fish there is evidence that in 1997 a significant proportion, 25 to 43%, of ... sexually mature fish were not coming into spawning condition. This introduces a bias leading to the ...

   Science Journal Paper : CCAMLR Science, Volume 6 (CCAMLR Science, Volume 6) : 37–46 : Auteur(s): Everson, I. and A.W. Murray

9. 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 ... . 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 ...

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

10. Feeding and food intake of Electrona carlsbergi (Tåning, 1932) Myctophidae

    by various methods was from 3.7 to 5.6% of fish body weight. The amount of food consumed by E ... . carlsbergi during the year in the waters to the south of the Antarctic Convergence is about 15 times fish ... fish body weight. The amount of food consumed by E. carlsbergi during the year in the waters to the ... south of the Antarctic Convergence is about 15 times fish body weight. Resume En ete et automne ... carlsbergi (Tdning) is one of the most abundant species of the Myctophidae family living in the Southern ... in different parts of the Southern Ocean. (Kozlov, Tarverdieva, 1989; Oven et al., 1990; Tarverdieva ...

    Science Journal Paper : Selected Scientific Papers, SC-CAMLR-SSP/7 (Selected Scientific Papers, SC-CAMLR-SSP/7) : 411–416 : Auteur(s): Gerasimova, O.V.

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