Résultats de la recherche
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Estimation of natural mortality for the Patagonian toothfish at Heard and McDonald Islands using catch-at-age and aged mark-recapture data from the main trawl ground
obtained using proportions-at-length and fishery- and year-specific age–length keys (ALKs) for years 1998 ... in R, based on alternative ordinary differential equations (ODE) for within-year population dynamics ... directly from the estimates of population numbers-at-age. The properties of these two models for estimation ... Paper Title: Estimation of natural mortality for the Patagonian toothfish at Heard and McDonald ... age frequencies within each fishing year. For an M of 0.155, the expected number of recaptures fitted ... along with two methods of applying an effective sample size. The estimation for these ver- sions of the ... used for the Antarctic toothfish was also 0.13 y–1, where this value was based on an analysis of ... fishery- and year-specific age–length keys (ALKs) for years 1998 to 2008. A large proportion of the ...
Science Journal Paper : CCAMLR Science, Volume 18 (CCAMLR Science, Volume 18) : 29–45 : Auteur(s): Candy, S.G., D.C. Welsford, T. Lamb, J.J. Verdouw and J.J. Hutchins
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A simulation study of the method of deriving natural mortality rate using data for Champsocephalus gunnari in Subarea 48.3
Paper Title: A simulation study of the method of deriving natural mortality rate using data for ... been correctly chosen. Data for Champsocephalus gunnari in Subarea 48.3 are used to show that the ... mortality, based on the construction of a regression between the rate of annual fishing mortality ... mortality rates and fishing mortality rates for the oldest age group by fishing year are estimated by the ... =e {.y- an .
for a> 0, Wa,y = WO,y = wl/2,y for a ... year Ey • A general procedure for the study of natural mortality rate specification with the use of ... it was better to use real data from the fishery for this purpose and as an example the C. gunnari ...
Science Journal Paper : Selected Scientific Papers, SC-CAMLR-SSP/8 (Selected Scientific Papers, SC-CAMLR-SSP/8) : 69–83 : Auteur(s): Gasyukov, P.S. and R.S. Dorovskikh
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A comparison between otoliths and scales for use in estimating the age of Dissostichus eleginoides from South Georgia
caught off South Georgia using otoliths and scales. For scales, we made impressions on acetate slides ... Paper Title: A comparison between otoliths and scales for use in estimating the age of ... result in large errors in age data for long-lived species, usually due to compression of scale circuli ... ; for otoliths, we used transverse sections prepared by baking and grinding the posterior and anterior ... . Sustainable exploitation rates should have been 20-30% of that based on age determinations from scales, in ... using scales than otoliths. There was evidence that for fish older t l~an 16 years (estimated using ... . MSE is an unbiased estimate for o2 within the design, however it is dependent on how the degrees of ... two readings. The bias for Reading 2 by Reader 1 was 0.51 years; the bias for Reading 2 by Reader 2 ...
Science Journal Paper : CCAMLR Science, Volume 8 (CCAMLR Science, Volume 8) : 75–92 : Auteur(s): Ashford, J.R., S. Wischniowski, C. Jones, S. Bobko and I. Everson
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Factors to consider in developing management measures for krill
Living Resources is given along with an outline of steps for the evolution of management procedures for ... Paper Title: Factors to consider in developing management measures for krill Abstract ... / Description: A brief review of the objectives of the Convention for the Conservation of Antarctic Marine ... are dependent on krill forms an integral part of objectives of the Commission for the Conservation of ... Convention for the Conservation of Antarctic Marine Living Resources is given along with an outline of ... year to year. The various techniques used to estimate the abundance of animal populations also give ... knowledge; for various reasons, errors will be made in applying conservation measures. Two types of errors ...
Science Journal Paper : Selected Scientific Papers, SC-CAMLR-SSP/7 (Selected Scientific Papers, SC-CAMLR-SSP/7) : 175–187 : Auteur(s): de la Mare, W.K.
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Spatial distribution of management measures, Antarctic krill catch and Southern Ocean bioregions: implications for conservation planning
Ocean bioregions: implications for conservation planning Abstract / Description: Systematic ... conservation planning for developing marine spatial protection includes analysis of the spatial distribution of ... season, 64% of the CAMLR Convention Area was open to fishing for at least one species. There were ... distribution of catch within the open fraction. For example, only 26% of the total area open to krill fishing ... Raymond and an anony- mous referee for constructive comments on this paper. References Ardron, J.A., H.P ... bioregionalisa- tion as an indicator of habitat, and catch data for Antarctic krill, Euphausia superba ... clipped to an accurate coastline dataset which was derived from two sources: the Antarctic coastline was ... accounts for only 1.3% of the Convention Area. Bioregion 6 (Antarctic shelves) similarly occurs in two ...
Science Journal Paper : CCAMLR Science, Volume 20 (CCAMLR Science, Volume 20) : 1–19 : Auteur(s): Grant, S.M., S.L. Hill and P.T. Fretwell
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A proposed management procedure for the toothfish (Dissostichus eleginoides) resource in the Prince Edward Islands vicinity
catches made. An MP with control parameter values specified is proposed for implementation based on the ... results of the trials. Given the importance of an adequate catch rate for the economic viability of the ... Paper Title: A proposed management procedure for the toothfish (Dissostichus eleginoides ... ‘Optimistic’, ‘Intermediate’, ‘Less Pessimistic’ and a ‘Pessimistic’ current status for the resource are ... following proce- dure: 1. Numbers-at-age ( ',y aN ) for the start of the year in which projections ... 20-year projec- tion period is zero under all OMs except for the Pessimistic one for which it is ... Bsp over the 20-year pro- jection period falling below 50% of Ksp is zero for the Optimistic and the ... years (i.e. 2008, 2009, etc. for year y’), the generated longline CPUE abundance indi- ces and longline ...
Science Journal Paper : CCAMLR Science, Volume 16 (CCAMLR Science, Volume 16) : 33–69 : Auteur(s): Brandão, A. and D.S. Butterworth
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The choice of procedure for deciding when to close fisheries regulated by CCAMLR: a simulation model
Paper Title: The choice of procedure for deciding when to close fisheries regulated by CCAMLR: a ... simulation model Abstract / Description: The methods, described in CCAMLR Conservation Measures, used for ... deciding the closure date for fisheries monitored by the Secretariat of CCAMLR, have been difficult to ... fluctuating random catch histories are simulated and the performance of four models for making closure ... when the TAC has been taken. There have now been two seasons for which the Secretariat has had to ... AC. Two models were used: • Type I catch - random catch rates where C is the catch rate for one ... catch rates will always contain an element of uncertainty, for some methods more than others. The more ... WRITE (*,'(4F8.4)') B,A,RATESTART DO 20 I=l,MAXPERIOD C use equation for uniform accelleration to ...
Science Journal Paper : Selected Scientific Papers, SC-CAMLR-SSP/9 (Selected Scientific Papers, SC-CAMLR-SSP/9) : 81–97 : Auteur(s): Agnew, D.J.
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The utilization of seabird censuses for krill monitoring
databases, calling for international cooperation on the subject. File: 16-Marschoff-et-al.pdf ... Paper Title: The utilization of seabird censuses for krill monitoring Abstract / Description ... correspondence analysis. Contour plotting, profile analysis and tests for equality of covariance matrices proved ... technique will allow the discrimination of krill levels by means of bird counts thereby providing an ... providing an efficient tool for statistical tests of significance. The most promising approach seems to be ... mentioned species are more or less suitable for direct observation, at the present state of the art it is ... test for multinormality, but will give an idea of the distributional· properties of data, which is ... krill abundance and comparisons from year to year. Contour plotting of the position measures for ...
Science Journal Paper : Selected Scientific Papers, SC-CAMLR-SSP/4 (Selected Scientific Papers, SC-CAMLR-SSP/4) : 393-425 : Auteur(s): Marschoff, E.R., J.G. Visbeek and L.R. Fontana
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The ecosystem approach to managing fisheries: achieving conservation objectives for predators of fished species
fisheries impact incidentally on an ecosystem, (ii) what should be the conservation objectives for predators ... Paper Title: The ecosystem approach to managing fisheries: achieving conservation objectives for ... in its infancy. A general approach is proposed for maintaining ecological relationships and providing ... for the recovery of depleted populations in food webs supporting fisheries. This paper addresses the ... fisheries impact incidentally on an ecosystem, (ii) what should b e the conservatio~l objectives for ... , iiicludiiig the potential for flow-on effects in the food web. Thus, what would be an operational objective ... 20-30 years, wl~ich is the critical period over which the system should not be irreversibly changed ... years (see text for details). Year Figure 7: Individual productivity for each predator in the trial ...
Science Journal Paper : CCAMLR Science, Volume 8 (CCAMLR Science, Volume 8) : 37–64 : Auteur(s): Constable, A.J
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Variations in echosounder calibration with temperature, and some possible implications for acoustic surveys of krill biomass
implications for acoustic surveys of krill biomass Abstract / Description: Accurate estimation of krill ... those applied in the Antarctic, even after adjustments have been made to account for differences in ... at both 38 and 120 kHz between calibrations conducted at the two locations. At 120 kHz, the required ... -reported by 2.8 dB, leading in turn to an under-estimation of krill biomass by 52.5%. Every effort should ... in continuous operation for at least two days on transit between the point of embarkation for the ... . Here we present calibration data for an EK500 system at 38, 120 and 200 kHz collected over a number ... on each of these occasions. Mean S, and TS transducer gains for each frequency derived from all ... ) calibration spheres required for the higher frequencies stationary in the beam and on axis. In addition, the ...
Science Journal Paper : CCAMLR Science, Volume 5 (CCAMLR Science, Volume 5) : 273–281 : Auteur(s): Brierley, A.S., C. Goss, J.L. Watkins and P. Woodroffe