Résultats de la recherche

1. Natural mortality rate in the mackerel icefish (Champsocephalus gunnari) around South Georgia

   provide an estimate that is unaffected by confounding effects mainly due to recruitment variation, but ... South Georgia Abstract / Description:  Information on natural mortality rates of the mackerel icefish ... impossible. Initial analyses for this study were undertaken using all of the above methods. In an ... year class: To test whether there is a significant difference between the two survivorship ... by Frolkina and Dorovskikh (1991) and Olsen (1955) for each year is set out in Figure 1. Analysis ... 0.475, and the mean by the Baranov method for the same year is 0.48 and not 0.80 as stated ...

   Science Journal Paper : CCAMLR Science, Volume 5 (CCAMLR Science, Volume 5) : 245–257 : Auteur(s): Everson, I

2. Consideration of major issues in ecosystem monitoring and management

   Ocean resources and highlights the need for information on harvested and dependent species, their ... bringing these various components together as an ecosystem approach to management is discussed. File ... / Description:  This paper outlines the requirements of an ecosystem approach to the management of Southern ... interactions and the manner in which their populations vary naturally. Large-scale interactions are catered for ... recruitment is randomly distributed between 1 000 and 2 000. From year 20 onwards for two randomly selected ... 10000 15000 0 10 20 30 40 50 60 70 80 90 100 Year Po pu la tio n si ze Recruitment fails twice ... 30–150 Calendar dateP ot en tia l r an ge fr om c ol on y Calendar date Foraging trip ... all the requirements of Article II will be met. This is for two reasons. Firstly, errors in ...

   Science Journal Paper : CCAMLR Science, Volume 9 (CCAMLR Science, Volume 9) : 213–232 : Auteur(s): Everson, I

3. Chilean krill fishery: analysis of the 1991 season

   paper summarises Chilean catch data for 1991. Special emphasis is given to the analysis of haul-by-haul ... for the year 1983, only in the Subarea 48.1, comprising from 5% to 100% of the kriU fishery in that ... was fished for two days (21 to 275 23 February) yielding 260 tonnes (CPUE = 12.9 tonnes hr -1 ... °S, 59°13'W. This patch was fished for another two days yielding 264 tonnes (CPUE = 9.3 tonnes hr -1 ... these two areas. Fishing season lasted 34 days. Thus for a given season, both areas would be treated as ...

   Science Journal Paper : Selected Scientific Papers, SC-CAMLR-SSP/8 (Selected Scientific Papers, SC-CAMLR-SSP/8) : 273–287 : Auteur(s): Marín, V.H., A. Mujica and P. Eberhard

4. Estimating optimal observer coverage in the Antarctic krill fishery

   vessels sampled each season, 20% of total season hauls sampled for krill and an equivalent or higher ... on board for about 30% of that season. They have achieved a rate of krill sampling equivalent to 18 ... is proposed that an efficient sampling proportion, at least for South Georgia, should be >50% of ... . The South Georgia data suggest that such strategies should be pursued for at least four years before ... , should be >50% of vessels sampled each season, 20% of total season hauls sampled for krill and an ... 75 78 76 24 18 A tl an ti c N av ig at or 20 05 30 3 54 40 74 ... been present on board for about 30% of that season. They have achieved a rate of krill sampling ... hauls set over the entire season by vessels which had an observer on board for some part of that ...

   Science Journal Paper : CCAMLR Science, Volume 17 (CCAMLR Science, Volume 17) : 139–154 : Auteur(s): Agnew, D.J., P. Grove, T. Peatman, R. Burn and C.T.T. Edwards

5. A functional division of Electrona carlsbergi (Tåning, 1932) area of habitat in relation to the latitudinal zonation of the Southern Ocean

   Southern Atlantic along two meridional transects at 17° and 20°W in the latitudes from 37°30' to 55°30 ... carlsbergi and also on searching for possible spawning areas of the species. During the survey the following ... the RV Vozrozhdenie (VNIRO, USSR) in March/April 1990 an integrated study survey was conducted in the ... 'S. The survey was mainly focussed on studies of distribution of adult and pre-spawning Electrona ... March/April 1990 an integrated study survey was conducted in the Southern Atlantic along two meridional ... AND METHODS From 20 March to 10 April 1989, two longitudinal transects were made along 17° and 200W ... in the latitudinal band between 37°30' and 55°30'S. The choice of these two meridians was dictated ... for spawning occur in ridge areas, due to powerful meandering currents and an increased level of gyre ...

   Science Journal Paper : Selected Scientific Papers, SC-CAMLR-SSP/7 (Selected Scientific Papers, SC-CAMLR-SSP/7) : 369–395 : Auteur(s): Zemsky, A.V. and S.A. Zozulya

6. Sensitivity investigation of the SDWBA Antarctic krill target strength model to fatness, material contrast and orientation

   for the body shape parameterisation can give a high source of uncertainty, and there is an urgent need ... TS of Antarctic krill (Euphausia superba) for use in the acoustic echo-integration method. In this ... study, the SDWBA TS pattern and frequency response behaviours at standard survey frequencies and animal ... the distribution of animal orientations. Due to the high variability of TS to realistic changes in ... rigorously if the scattering as a function of size and frequency for an individual (i.e. target strength ... relationship for the body shape parameterisation can give a high source of uncertainty, and there is an urgent ... used to develop an inversion protocol in a multifrequency context for estimating the mean length and ... values. The last parameter describes the ori- entation of individuals within an aggregation. For a ...

   Science Journal Paper : CCAMLR Science, Volume 18 (CCAMLR Science, Volume 18) : 97–122 : Auteur(s): Calise, L. and G. Skaret

7. Notothenia (P.) guntheri stock status and TAC estimation in the area of Shag Rocks (Subarea 48.3)

   . guntheri abundance was estimated as 227 thousand tonnes (using all the above mentioned methods). For 1986 ... (Subarea 48.3) Abstract / Description:  Data on age composition of catches and fishing efforts for 1979/80 ... intensity (F) in the predicted period is equal to the mean value of fishing mortality for the main ... 1987/88; (c) Fishing intensity in the predicted period is F 0.1. In the first two cases TAC is 12.3 ... biomass by years (thousand tonnes). Stock status and TAG prediction, if F is an average value for the ... on age composition of catches and fishing efforts for 1979/80-1987/88 were used to analyse N ... estimated as 227 thousand tonnes (using all the abovementioned methods). For 1986/87 the figure was only ... the predicted period is equal to the mean value of fishing mortality for the main commercially taken ...

   Science Journal Paper : Selected Scientific Papers, SC-CAMLR-SSP/5 – Part II (Selected Scientific Papers, SC-CAMLR-SSP/5 – Part II) : 53-68 : Auteur(s): Shust, K. and R. Borodin

8. Length-based assessments revisited – why stock status and fishing mortality of long-lived species such as toothfish cannot be inferred from length-frequency data alone

   status and fishing mortality for long-lived fish species such as Patagonian toothfish (Dissostichus ... other informative estimators for stock abundance and productivity, the review and the simulations ... highlight that interpretation of raw length-frequency data and single length-based indicators for stock ... over two or three decades (Constable et al., 2000). At the core of this approach are rules for ... fishery operations for an assessment of the sta- tus and productivity of the fished stocks to estimate ... mortality for Patago- nian toothfish as an example of a long-lived fish species are illustrated. stock ... with stock abundance or a meaningful reference point must be known if they are used as an index for ...

   Science Journal Paper : CCAMLR Science, Volume 18 (CCAMLR Science, Volume 18) : 57–73 : Auteur(s): Ziegler, P.E., D.C. Welsford and A.J. Constable

9. A first step towards modelling the krill–predator dynamics of the Antarctic ecosystem

   , together with suggested further areas for investigation. Amongst the key inferences of the study are that ... population trends without the need for recourse to environmental change hypotheses. A model is developed ... including krill, four baleen whale (blue, fin, humpback and minke) and two seal (Antarctic fur and crabeater ... krill, to explain observed trends – crabeater seals seemingly play an important role and constitute a ... – crabeater seals seemingly play an important role and constitute a particular priority for improved ... using Bayesian approaches yields an annual 7.3% (95% CI: 1.4–11.5%) increase for this species since ... reported an indication of the recovery of breeding stock C – east Africa. For breeding stock A (Brazil ... , a slight increasing trend is evident for the year classes from 1990. Direct observations of the age ...

   Science Journal Paper : CCAMLR Science, Volume 13 (CCAMLR Science, Volume 13) : 217–277 : Auteur(s): Mori, M. and D.S. Butterworth

10. Investigation of bias in the mark–recapture estimate of toothfish population size at South Georgia

    an average movement rate downwards when fish entered a high-density box (as indicated by high CPUE ... situations. It produced a near-perfect estimate of stock size when there was an ideal distribution of tags ... indicated that the Petersen estimator produced an underestimate of true population size. Although this paper ... exploitable population size made for Subarea 48.3, it is concluded that the particular distribution of tag ... correctly capture movement reversals – where an animal moves west one year and back east the next, for ... of toothfish typically move only 20–30 km each year (Marlow et al., 2003). This paper investigates ... number of tagged fish alive and available for capture in box k in year t. Two alternative methods were ... calculated for those two years. results Model behaviour The model was subjected to a number of tests to ...

    Science Journal Paper : CCAMLR Science, Volume 13 (CCAMLR Science, Volume 13) : 47–63 : Auteur(s): Agnew, D.J., G.P. Kirkwood, J. Pearce and J. Clark

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